INTRODUCTION
The term meconium is derived from the Greek word ‘Mekonion’,
a word for Opium/Poppy juice. Aristotle coined the term meconium and reported
opium like effects in neonates born through Meconium stained Amniotic Fluid.
Meconium is the first intestinal secretion from fetus. It
starts as early as 10 weeks of gestation and incidence of intrauterine passage
of meconium increases with the gestational age.
Amniotic fluid is the fluid present in amniotic sac, which
surrounds the fetus, provides nutrition and maintains temperature of fetus.
Meconium may be passed during the intrauterine life in about
7-22% cases. Meconium passage is usually secondary to foetal hypoxia. Once
meconium is passed, it contaminates amniotic fluid and exposes fetus to
meconium.
Many studies have shown meconium stained amniotic fluid is
associated with increased rate of foetal distress, increased perinatal
morbidity and mortality.
Meconium staining of amniotic fluid during labour must be
managed by a team of Obstetrician and Paediatrician well versed in neonatal
resuscitation to: –
- Prevent intrauterine hypoxia.
- Prevent intrauterine meconium aspiration.
- Prevent meconium aspiration at birth.
Amnioinfusion is instillation of ringer lactate / normal
saline into amniotic cavity either trans abdominally or transcervically. Trans cervical amnioinfusion is instillation
of fluids through cervix during labour once membrane ruptures.
Once meconium stained amniotic fluid is detected during
labour, especially in moderate to thick meconium, amnioinfusion is done.
Amnioinfusion dilutes and washes away thick meconium and
increase amniotic fluid index.
Many studies have shown that amnioinfusion in moderate to
thick Meconium stained amniotic fluid improves obstetric outcome, decrease in
operative delivery and neonatal outcome. However few studies show no
improvement in obstetric or neonatal outcome.
Studies have shown conflicting reports regarding the role of
amnioinfusion in meconium stained amniotic fluid, so this study was conducted
to evaluate the role of transcervical amnioinfusion in intrapartum management
of meconium stained amniotic fluid.
AIMS & OBJECTIVES
Although intrapartum amnioinfusion was introduced more than
2 decades ago and is practised widely in United States, reports of its regular
use in developing countries are scarce. This is probably due to prohibitive
cost of a specially designed intrauterine catheter, and lack of equipment for
electronic foetal monitoring.
Amnioinfusion is an inexpensive intervention whereas the
cost of a caesarean section is about 50-100 folds that of amnioinfusion in a
similar setting. In addition, shorter hospital stay reduces the cost of
childbirth.
Therefore the present study is designed to evaluate its mode
of delivery, maternal and perinatal outcome & cost benefit analysis in the
form of operative intervention rate in this set-up.
So the aims and specific objectives of this study were----
Whether transcervical amnioinfusion has got any effect in
mode of delivery in a labour complicated by meconium stained amniotic fluid.
(b) The effect
on neonate by assessing 1 min & 5 min Apgar Score and Sick Newborn Care
Unit (SNCU) admission.
(c) The effect
of amnioinfusion in reducing the incidence of meconium aspiration syndrome and
perinatal mortality.
(d) To study
any complication of the procedure.
REVIEW OF LITERATURE
HISTORY
The term meconium is derived from the Greek word ‘Mekonion’,
a word for Opium/Poppy juice. Aristotle coined the term meconium and reported
opium like effects in neonates born through Meconium Stained Amniotic Fluid
(MSAF). There have been references to meconium in association with perinatal
deaths from as early as 1676.
Williams 1 observed in 1903 that a characteristic sign of
impending asphyxia is the escape of meconium. However obstetricians realized that the detection of
meconium during labour is problematic in the prediction of foetal distress or
asphyxia.
Katz & Bowes (1992) emphasized the prognostic
uncertainty of meconium by referring to the topic as a ‘murky subject’.
Meconium may be passed during the intrauterine life in about 7-22% cases. The first
intestinal discharge from newborns is Meconium, which is a viscous, dark green
substance, composed of intestinal epithelial cells, lanugo, mucus, and
intestinal secretions, such as bile. Intestinal secretions, mucosal cells, and
solid elements of swallowed amniotic fluid are the 3 major solid constituents
of meconium.
Water is the major liquid constituent, making up 85-95% of
meconium. Intrauterine foetal distress can cause passage of meconium into the
amniotic fluid further leading to Meconium Aspiration Syndrome (MAS).
In their review Ramin et3 describes, “Meconium in amniotic
fluid is Environmental Hazard”.
There is a decreasing trend in the incidence of meconium
aspiration syndrome, and numerous studies from around the world have been
unable to find any association between meconium stained amniotic fluid and
maternal age, maternal weight, parity, duration of labour, type of high risk
factors, Oxytocin induction, type of anaesthesia, maternal smoking or alcohol
consumption, sex, or weight of the foetus.
MECONIUM STAINED AMNIOTIC FLUID
Meconium may be passed during the intrauterine life in about
7-22% cases. Meconium staining of amniotic fluid begins 1 to 3 hours after the
fetus passes meconium and increases with gestational age.
Meconium is found in the foetal gut from 10 weeks gestation. There
appears to be a link between gestational age and meconium passage. Meconium
passage is infrequent / rare before 32- 34 wks gestation.
The incidence of meconium passage during labour increases
with gestational age and reaches approximately 30% at 40 weeks gestation and
50% at 42 weeks. Meconium passage is
seldom seen in preterm foetuses.
TABLE – 1: Meconium passage as function of gestational age
SERIES
INFANTS WITH MECONIUM
PASSAGE (%)
Usher et al
39-40 wk
15.3
41 wk
27.0
>42 wk
31.5
Ostrea and
Nazvi
<38 wk
4.3
39-42 wk
6.0
>42 wk
52.0
Eden et al
39 wk
13.5
40 wk
19.4
42 wk
25.5
>42 wk
28.9
Steer et al
<36 wk
3.0
36-39 wk
13.0
40-41 wk
19.0
>42 wk
23.0
Meconium passage into the Amniotic fluid may be ante partum
or an intrapartum event. Various theories have been suggested to explain foetal
passage of meconium and may, impart, explain the tenuous connection between the
detection of meconium and foetal compromise.
Intrauterine hypoxia causes increased intestinal peristalsis and relaxed
anal sphincter resulting in meconium passage. Alternatively, evidence exists
suggesting that meconium passage results from neural stimulation of a mature
gastrointestinal tract. As the fetus approaches term, the gastrointestinal tract matures,
and – motilin secreted.
Umbilical cord motilin levels are higher in infants who have
passed meconium compared with those infants with clear amniotic fluid, and
motilin levels are low in premature infants than in term and post term infants.
Thirdly meconium passage could also follow vagal stimulation from common but
transient umbilical cord compression and resultant increased peristalsis.
Foetal release of meconium could also represent
physiological processes. Milleret al.7have stated, “The presence of meconium in
amniotic fluid without sign of foetal asphyxia…is not a sign of foetal
distress….”
Factors that promote the passage of meconium in Utero
include the following:
(a) Pregnancy
that lasts 42 weeks or longer.
(b) Secondary
to a hypoxic stress.
(c) Placental
insufficiency.
(d) Transient
rise of PCO2 or fall in PO2 in the umbilical arteries due to
pressure in the umbilical cord without metabolic
acidosis.
(e) Maternal
hypertension, Preeclampsia.
(f) Oligohydramnios.
(g) Maternal
drug abuse, especially of tobacco and cocaine.
(h) Foetal
distress during labour.
(i) Transient
pressure on the scalp during labour.
(j) Amnionitis.
(k) Idiopathic.
GRADING OF MECONIUM
Driscoll et al 8 studied meconium stained amniotic fluid and
graded according to consistency. Grade –1 is light meconium stained fluid,
which remained transparent when, collected in test tube. Grade -2 indicates an
opaque solution of meconium in amniotic fluid. Grade –3 is meconium undiluted
by any amniotic fluid.
Trimmer and Gilstrap using the weight percent of the solid
component of meconium described the “meconiumcrit.” 10 ml of MSAF is taken in a
graduated test tube and centrifuged at 1000 rpm for 10 minutes. The volume of
the meconium sediment is expressed as percentage.
<10% solid component is considered light meconium,
10% to 30% considered moderate meconium, and
> 30% considered thick meconium.
It is important to estimate the quantity of meconium in the
amniotic fluid, because, one of the
determinants of Meconium aspiration syndrome (MAS) and neonatal mortality arising
out of it, is the amount of meconium passed in the amniotic fluid by the fetus.
The “meconiumcrit” has been found to be unrelated to sex,
birth weight, gestational age, foetal distress, maternal weight, age, parity, antenatal risk factors or Premature
Rupture Of Membrane (PROM).
Sandhu et al studied 50 cases and depending on nature of
meconium divided MSAF into three groups thin, moderate and thick, and Incidence
was 46%, 12% and 15% respectively. One study evaluated patients with meconium
passage during early and late labour and graded the presence of meconium as
light or heavy. A prolonged second stage of labour, an increased incidence of
operative intervention, such as forceps delivery and caesarean section, as well
as a significantly higher incidence of neonatal morbidity and mortality,
particularly in association with meconium aspiration, were all associated with
heavy meconium passage early in labour. These abnormal heart rate patterns
included late decelerations, severe variable decelerations, and decreased
variability.
Although the aetiology is not well understood, effects of
meconium are well documented. Meconium directly alters the amniotic fluid,
reducing antibacterial activity and subsequently increasing the risk of
perinatal bacterial infection. Additionally, meconium is irritating to foetal
skin, thus increasing the incidence of erythema toxicum. However, the most
severe complication of meconium passage in utero is aspiration of meconium
stained amniotic fluid before, during, and after birth.
MECONIUM ASPIRATION SYNDROME
The passage of thick meconium in utero puts the neonate at
risk for meconium aspiration syndrome (MAS). Meconium aspiration syndrome
develops in 11to58% (mean 35%) of infants delivered from meconium-stained
amniotic fluid and is associated with increased perinatal morbidity and
mortality. Aspiration of meconium is regarded as an intrauterine event,
although it can also happen during delivery with the baby's first breaths in
foetuses with Oligohydramnios and cord compression.2 Aspiration of meconium is
caused by hypoxia and hypercapnia, which work together to stimulate foetal
gasping. Meconium aspiration syndrome is most strictly defined as the presence
of any meconium below the vocal cords.
Coltart et al. 13 in his study gave strict criteria to
diagnose MAS, which include a triad of--
1. The presence of meconium-stained
amniotic fluid, meconium in trachea at birth followed subsequently by
tachypnoea but without evidence of infection.
2. Chest X – ray consistent with
MAS-scattered opacities with tendency to over expansion of lungs.
3. Histological
confirmation of meconium in alveoli at autopsy.
Risk factors for MAS are foetal distress during labor,
Oligohydramnios, thick meconium, placental insufficiencies and maternal drug
abuse, especially of tobacco and cocaine.
Patho-physiology of meconium aspiration syndrome:
Meconium is a sterile admixture of numerous chemicals,
including mucous glycoprotein, swallowed vernix caseosa, gastrointestinal
secretions, bile, pancreatic and liver enzymes, plasma proteins, minerals, and
lipids.
Mucopolysaccharides compose 80% of meconium's dry weight.
The concentration of pancreatic and liver enzymes varies with gestational age.
While it is not known exactly which chemicals produce the
violent inflammatory response seen in even mild MAS, it is believed that these
are chiefly responsible. Biopsy samples
reveal polymorphonuclear cell and macrophage infiltration. Alveolar edema soon
occurs, along with hyaline membrane formation. Pulmonary haemorrhages may
occur. Pathology specimens have also shown micro thrombi in the pulmonary
vasculature.
Some investigators have found involvement of the distal
arterioles within the lungs.
Normal foetuses have rapid and shallow respiratory movements
in utero. If a fetus becomes distressed and hypoxemic these rapid movements
cease. If hypoxia persists the foetal apnoea is replaced by deep gasping
respiratory movements. The foetal lung fluid is replaced by aspirated amniotic
fluid which contains meconium because foetal hypoxia can also stimulate colonic
contraction and evacuation of meconium into the amniotic fluid. The pulmonary
problems therefore are due to a combination of aspirated meconium causing
mechanical obstruction of the major airways and a more peripheral chemical
pneumonitis. If obstruction is complete, death occurs. Much more likely is
partial airway obstruction with peripheral air trapping, often leading to air
leak complications.
Prolonged exposure of the smaller airways and alveoli to the
necrotizing effects of meconium can result in chemical pneumonitis with
alveolar collapse and cellular necrosis. This results in increased airway
reactivity and a generalized obstructive phenomenon that usually resolves
slowly during the first year of life. Treatment is optimized to clear the
aspirated amniotic fluid and meconium by immediate postnatal suctioning before
the meconium disseminates peripherally. Although meconium is sterile per se it
can be a good culture medium for microorganisms, especially E. coli and
Staphylococcus aureus. Prevention of MAS remains problematic. There is usually
lack of knowledge of the timing of meconium passage in utero, even in labour.
Effect of meconium on lung.
Airway obstruction:
Complete obstruction of the airways results in atelectasis.
Partial obstruction causes air trapping and hyper distension
of the alveoli. Hyper distension of the alveoli occurs from airway expansion
during inhalation and airway collapse around inspissated meconium in the
airway, causing increased resistance during exhalation. The gas that is trapped,
hyper inflating the lung may rupture into the pleura (pneumothorax),
mediastinum (pneumomediastinum), or pericardium (pneumo-pericardium).
Surfactant dysfunction:
Several constituents of meconium, especially the free fatty
acids (eg, palmitic , stearic, oleic), have a higher minimal surface tension
than surfactant and strip it from the
alveolar surface, resulting in diffuse atelectasis.
Chemical pneumonitis:
Enzymes, bile salts, and fats in meconium irritate the
airways and parenchyma, causing a diffuse pneumonia that may begin within a few
hours of aspiration. All of these pulmonary effects can produce gross
ventilation-perfusion (V-Q) mismatch. To complicate matters further, many
infants with meconium aspiration syndrome (MAS) have primary or secondary
persistent pulmonary hypertension of the newborn (PPHN) as a result of chronic
in utero stress and thickening of the pulmonary vessels. Finally, though
meconium is sterile, its presence in the air passages can predispose the infant
to pulmonary infection.
MAS can present mildly as transient respiratory distress or
severely as respiratory failure with hypoxemia, acidosis, and pulmonary
hypertension. Classically, these babies are post mature and show signs of
weight loss and yellow-stained nails, skin, and cord Rarely, MAS occurs before
38 weeks of gestation. Babies with meconium aspiration syndrome may have the
following symptoms
- Cyanosis,
or a bluish skin colour, at birth
- Difficult
breathing or absence of breathing
- Thick,
greenish amniotic fluid in the mouth and throat at birth
Poor muscle tone.
Modality of treatment for MAS
When meconium is detected during early labour, amnioinfusion
with warm sterile saline may be beneficial. This procedure dilutes meconium in
the amniotic fluid; therefore, incidence of foetal distress, operative delivery
and the severity of aspiration may be minimized.
In order to reduce the risk of meconium aspiration, Carson
et al. recommended oral De Lee tube suction by the obstetrician upon delivery
of the baby's head. This is done before the infant takes its first breath.
Tracheal intubation and meconium suction by the paediatrician are then
performed. When aspiration occurs, intubation and immediate suctioning of the
airway can remove much of the aspirated meconium.
The American Academy of Paediatrics Neonatal Resuscitation
Program Steering Committee has promulgated the following guidelines for
management of the baby exposed to meconium:
If the baby is not vigorous (Apgar 1-3):
Suction the trachea soon after delivery (i.e. before the
first breath).
Suction for no longer than 5 seconds. If no meconium is
retrieved, do not repeat intubation and suction.
If meconium is retrieved and no bradycardia is present,
reintubate and suction.
If the heart rate is low, administer positive pressure
ventilation and consider suctioning again later.
If the baby is vigorous (Apgar >5):
Clear secretions and meconium from the mouth and nose with a
bulb syringe or a large-bore suction catheter. In either case, the remainder of
the initial resuscitation steps should ensue: dry, stimulate, reposition, and
administer oxygen as necessary. Linder et al Immediate tracheal suction is not
a harmless intervention, and should be considered superfluous in a vigorous
term neonate born with MSAF.
Intervention
Maintain an optimal thermal environment and minimal handling
because these infants are agitated
easily and quickly become hypoxemic and acidotic Continue respiratory care, Oxygen therapy via hood or
positive pressure is crucial in maintaining adequate arterial oxygenation. If
mechanical ventilation is required, make concerted efforts to minimize the mean
airway pressure and to use as short an inspiratory time as possible. Use of
surfactant has not yet been proven to be efficacious in this setting and is
under investigation. Although conventional ventilation commonly is used initially,
oscillatory, high frequency, and jet ventilation are alternative effective
therapies. Hyperventilation to induce hypocapnia and respiratory alkalosis is
used as primary therapy for pulmonary hypertension. Inhaled nitric oxide has
displaced the use of most intravenous pulmonary vasodilators. Pay careful
attention to systemic blood volume and Blood Pressure. Volume expansion,
transfusion therapy, and systemic vasopressors are critical in maintaining
systemic BP greater than pulmonary BP, thereby decreasing the right-to-left
shunt through the patent ductus arteriosus. Extra Corporeal Membrane
Oxygenation (ECMO) is employed if all other therapeutic options have been
exhausted.
MSAF AND PERINATAL OUTCOME
MSAF occurs in 7 to 22% of pregnancies and it is associated
with significantly higher incidence of neonatal morbidity and mortality,
particularly in association with meconium aspiration. MAS develop in 2% of
cases. Ramin et al states that 1% infants developed MAS and 45% foetal
acidemia. MAS were associated with correlates of foetal jeopardy during labour
and delivery for example Fetal Heart Rate (FHR) abnormality, caesarean delivery
for non-reassuring FHR patterns, as well as Forceps delivery and low apgar
score.
Sandhu et al 10 studied 50 cases with MSAF and noted foetal
heart rate variation in 21.7% of thin MSAF, 33.3% with moderately thick and
46.6%with thick meconium. Low apgar (<7) in 13.3%in thick MSAF as compared
to none in thin MSAF and the overall perinatal mortality was 6%, perinatal
morbidity 20% and incidence of caesarean rate 40% in thick MSAF compared to
13.6% in thin MSAF.
Bhide et al : studied 174 babies out of 2890 deliveries and
states meconium passage in utero is considered a serious neonatal disorder
causing increased neonatal morbidity.
Nathan et al states, meconium in amniotic fluid is an
obstetric hazard with small but significantly increased risk of adverse foetal
neonatal outcome. Incidence of perinatal mortality increased from0.3 to 1.5 per
1000 and severe foetal acidemia at birth-increased from 3/1000 to 7 per 1000,
increase in caesarean rate from 7 to 14%.
Narli et al noted that neonates with thick meconium, as
compared to those with thin meconium appeared to have significantly greater
rates of acidemia, low apgar score at 1min and 5 min, more need for
resuscitation and higher mortality rate. MAS and hypoxic ischemic
encephalopathy were also higher in infants with thick meconium.
Miller et al Have not found MSAF to herald a poor outcome
unless other signs of foetal distress are present. His study has reported that
Meconium Stained liquor is a poor predictor of foetal asphyxia, acidosis or
neonatal outcome.
METHODS TO DECREASE MECONIUM ASPIRATION.
Suppressing of fetal breathing:
Thinking that first breath is responsible for MAS,
previously it was tried to reduce MAS by giving narcotic and suppressing breathing.
Goodlin et al advocated sedating fetus in utero by administering narcotic drug
to mother with MSAF in order to reduce foetal respiration and subsequently MAS.
Further Dooley et al found no evidence
that maternally administered narcotic in labour reduces MAS in newborn.
Suctioning:
Carson et al. advocated oral De Lee tube suction by
obstetrician followed by tracheal intubation and suction of meconium by the
paediatrician, all before infants first breath. Upon delivery of the head of
the baby, careful suctioning of the posterior pharynx decreases the potential
for aspiration of meconium. The combined obstetric paediatric approach
(perineal suctioning/intubation) to infant tracheal suctioning at delivery was
described in a study that assumed that most meconium aspiration occurs during
delivery.
Subsequently, however, it has been well documented that the
combined technique of aggressive neonatal suctioning at delivery failed to
eliminate all cases of meconium aspiration syndrome. A 2 percent incidence of
this syndrome that persisted despite suctioning at delivery is believed to be
due to foetal gasping and antenatal aspiration of thick meconium fluid, but the
severity is reduced. Immediate tracheal suction is not a harmless intervention,
and should be considered superfluous in a vigorous term neonate born with
meconium stained amniotic fluid.
Physiotherapy
Physiotherapy has been tried to reduce MAS but is of less
use.
Amnioinfusion:
The risk of meconium aspiration is high in patients,
particularly when it is associated with episodes of foetal hypoxemia. Thin
meconium is not associated with an increased perinatal mortality rate or with
an increased incidence of meconium aspiration syndrome. Therefore, any
mechanism by which thick meconium can be converted to thin meconium in the
already potentially compromised fetus is postulated to have a positive affect
on neonatal outcome--specifically, a decreased incidence of meconium aspiration
syndrome.
Amnioinfusion was first described by Carey, at a
postgraduate obstetrics and gynaecology course in 1957, but did not receive
attention in clinical practice until the 1980s. In 1976, Gabbe et al. demonstrated in a monkey model that the
removal of amniotic fluid produced variable decelerations of the foetal heart
rate (FHR) tracing and that restoration of the amniotic fluid volume by
infusing normal saline solution eliminated the decelerations. They demonstrated
that variable decelerations related to Oligohydramnios and cord compression
could be corrected by amnioinfusion, providing a "cushion" for the
umbilical cord.
TRANSCERVICAL AMNIOINFUSION:
It was first described by Miyazaki & Taylor in 1983 as
an intrapartum procedure. Miyazaki and Navrez in1985 used Amnioinfusion (AI)
for resolution of variable deceleration. When meconium is detected,
administering amnioinfusion with warm sterile saline may be beneficial. This
procedure dilutes meconium in the amniotic fluid; therefore, the severity of aspiration
may be minimized.
Stephen.et al 26 compared intrapartum Amniotic Fluid Index
(AFI) and its relationship to foetal distress. AFI was measured in 50
consecutive labouring patients. Women with low AFI had a higher incidence of
abnormal foetal heart rate during the first stage of labour (64% vs. 20%,
p=0.02), meconium grade II and III at delivery (64% vs. 35%, p=0.05), and
operative delivery for foetal distress (57% vs. 17%, p=0.02).
Amnioinfusion theoretically restores normal amniotic fluid
volume and cushions the umbilical cord, which reduces cord compression,
allowing for the resumption of normal function as demonstrated by net efflux of
aspirated meconium and amniotic fluid in the previously hypoxic or asphyxiated
fetus. Most studies have reported a decrease in newborn respiratory
complications resulting from meconium aspiration in patients who receive
amnioinfusion.
If the presence of meconium below the vocal cords and
neonatal acidemia increase the risk for meconium aspiration syndrome prevention
of these complications may reduce the severity of meconium aspiration syndrome.
It is challenging to distinguish between the effects of amnioinfusion that may
result from dilution of meconium and those that result from replenishment of
amniotic fluid volume because the presence of thick meconium indicates a
reduction in the volume of amniotic fluid in which the meconium is diluted.
Transcervical Amnioinfusion Protocol
The procedure is straight forward and uses equipment found
in most hospital labour and delivery suites, including the following: a double
lumen intrauterine pressure catheter, normal saline solution at room
temperature, a foetal monitor and intravenous tubing. Although not required,
continuous close monitoring using a foetal scalp electrode is recommended. To
date, no benefit has been demonstrated for the use of infusion pumps or
solution warmers.
After obtaining informed consent, a vaginal examination is
performed to evaluate for cord prolapse, establish dilatation and confirm
presentation. The foetal scalp electrode is placed, followed by an intrauterine
pressure catheter to document resting tone (< 15 mm Hg). The normal saline
is linked to the intravenous tubing. The tubing is primed as it would be for
intravenous use. The tubing is then inserted into the infusion port on the
three-way stopcock of the intrauterine pressure catheter.
Various protocols for Intrapartum Amnioinfusion.
In Collaborative Randomised Amnioinfusion for Meconium
Project (CRAMP)-1: first 15
ml/min was given till 800 ml was transfused then 3
ml/min for rest of duration of labor.
CRAMP-2: used 500 ml over 30 min followed which another 500
l was given 30 drops / min.
800 ml bolus over 1 hour followed by continuous infusion of
180 ml/hr.
500 ml normal saline over 30 min followed by 3 ml/min.
600 ml over first hour and followed it with 150 ml/hr till
full cervical dilatation.
Amnioinfusion for Oligohydramnios, 500 normal saline over
20-30 min if amniotic fluid index <
5,then additional 500 ml was infused, if AFI 5-10 additional 250 ml was
introduced.
Fernand arias mentions use of 250 ml in 30 min and another
250 ml in next 30 min if required in cases of PROM, cases with foetal distress
and 200 -300 ml over 30 min for variable
deceleration.
TRANSCERVICAL AMNIOINFUSION
Indications
Thick particulate meconium staining of the amniotic fluid.
Repeated severe variable foetal heart rate decelerations
not responsive to
conventional therapy.
Oligohydramnios.
Relative contraindication for Amnioinfusion
Polyhydramnios,
Uterine hyper tonicity, multiple gestations, Amnionitis, Foetal anomaly,
uterine anomaly, severe foetal distress, Non vertex presentation, Placenta
previa, Abruptio placenta.
Risks / complications are
The greatest attractions of amnioinfusion have been that it
is relatively easy to perform, inexpensive and safe. Amnioinfusion has been
considered effective, easy to perform and safe. Although reports of severe or
morbid complications associated with amnioinfusion have been rare, these complications
are still a cause for concern. Few acute events have been attributed to
Amnioinfusion. Isolated cases of umbilical cord prolapse have been reported,
but they were well within the quoted occurrence rate of prolapse in pregnancies
with vertex presentation where Amnioinfusion was not used.
Other reported infrequent complications of amnioinfusion
include one case of uterine scar disruption and one case of iatrogenic
polyhydramnios and elevated intrauterine pressure during amnioinfusion, which
led to foetal bradycardia.
Five cases of amniotic fluid embolism have been reported in
the medical literature. All were
associated with other previously reported risk factors for amniotic fluid
embolism.
Electrolyte abnormalities after amnioinfusion occurred in
animal models; however, in one study, no significant changes were found in
newborn serum electrolyte levels. One incidence of a temporal relationship
between amnioinfusion and the unexpected development of respiratory failure in
a healthy parturient has been reported, however; cause and effect were not
established.
There are failures related to amnioinfusion. The possible
causes for failure are inadequate infusions, rapid progression to second stage
of labour and Cord complications; however, the cause of the greatest majority
of failures of the procedure to improve outcomes is unknown.
TABLE-2: Complications associated with amnioinfusion 38
Amnionitis
7 (4%)
Hyper tonus uterus
27 (14%)
Rupture uterus
4 (2%)
Maternal cardiac or respiratory compromise
3 (2%)
Abnormal FHR
17 (9%)
Maternal death
2 (1%)
Others
10 (50%)
A
prospective meta analysis study conducted by John Pierce et al analysed
thirteen studies and found that Intrapartum amnioinfusion significantly reduced
the frequency of MAS (OR 0.30; 95% CI 0.19,0.46) of meconium below vocal cords,
and neonatal acidemia. Significantly lower overall caesarean rate (OR 0.74; 95%
CI 0.59, 0.93) without increase in endometritis.
Another study by Cialone et al included 47 patients in the
study group and 58 patients in the control group. The proportion of neonates with meconium
below the vocal cords was reduced in the study group (two of 47 vs. 36 of 58,
p<0.001). Umbilical artery pH was increased in the study group neonates
(7.29 +/- 0.01 vs. 7.25 +/- 0.009, p<0.05). The rate of neonatal acidemia
was reduced in the study group (4 of 45 vs. 12 of 50, p < 0.05). The rate of
meconium aspiration syndrome was reduced in the study group (1 of 47 vs. 8 of
58, p < 0.05). Maternal and neonatal morbidity rates were similar, and
concluded that prophylactic amnioinfusion should be considered a possible
addition to the intrapartum management of patients with particulate
meconium-stained amniotic fluid.
A study conducted by Wenstrom et al included 85 patient
receiving amnioinfusion and found that patients receiving amnioinfusion had
significantly fewer low 1 min Apgar score, less meconium below vocal cord, and
a significantly lower incidence of
operative delivery.
A Multi-centered randomized study; a CRAMP I study showed
that Caesarean section rates were similar (amnioinfusion 70/167 vs. controls
68/159: RR 0.98, 95%CI 0.76-1.26). The incidence of MAS was lower than expected
on the basis of previous stud y (4/162 vs. 6/163; RR 0.67, 95%CI 0.19-2.33)
there were no perinatal death. There were no significant differences between any
of the subsidiary outcomes.
In another study (CRAMP II) there was no difference in risk
for caesarean section in two groups (amnioinfusion 9.5% vs. 12.3%; RR 0.84, 95%
CI 0.53-1.32). MAS was significantly less frequent in amnioinfusion group (3.1%
vs. 12.8%; RR 0.24, 95%CI 0.12 0.48), and there were trends towards few
perinatal deaths (1.2% vs. 3.6%; RR 0.34, 95%CI 0.11-1.06).
In another study by Eriksen et al Amnioinfusion was given to
65patients and 59 patients as control. Incidence of foetal distress (16 of 65
vs. 8of 59) and caesarean section for foetal distress (7of 65 vs. 7of 59) was
not significantly different between two groups. The rate of meconium below
vocal cords (1 of65 vs. 8 of 59) was significantly lower in patients receiving
amnioinfusion (RR 0.09, CI 0.02 and 0.82, p=0.02). Two cases of MAS occurred in
control group, none in amnioinfusion group.
Sadavsky et al. 42 conducted a prospective, randomised study
to assess the safety and effectiveness of prophylactic transcervical
amnioinfusion. They found that there was no amnioinfusion-related complication
and that there was no meconium below the vocal cords (0% vs. 29%, p0.05). They
also came to the conclusion that transcervical amnioinfusion is a
straightforward, safe procedure.
A study by Hofmeyr 40 analysed twelve studies, most
involving small number of participants were included. Amnioinfusion was linked to a lower risk of
the following conditions under limited perinatal surveillance: meconium
aspiration syndrome (relative risk 0.24, 95% confidence interval 0.12 to 0.48);
neonatal hypoxic ischemic encephalopathy (relative risk 0.07, 95% confidence
interval 0.01 to 0.56); and neonatal ventilation or intensive care unit
admission (relative risk 0.56, 95% confidence interval 0.39 to 0.79); there was
also a He concluded Amnioinfusion is associated with improvements in perinatal
outcome, particularly in settings where facilities for perinatal surveillance
are limited. The trials reviewed are too small to address the possibility of
rare but serious maternal adverse effects of amnioinfusion.
Another study by Spong and colleagues, addressed this issue
in a prospective, randomized study in which patients assigned to a control
group received "standard care," and a study group, which received
included Amnioinfusion for repetitive variable decelerations. There was no
difference in outcome between the prophylactic- Amnioinfusion group and the
standard-care group. They concluded that the benefit of Amnioinfusion in
patients with Meconium-stained amniotic fluid may be the result of alleviation
of variable foetal heart rate decelerations, rather than meconium dilution.
Amnioinfusion among women attempting vaginal birth after caesarean delivery is
found to be safe.
TABLE–3: Intrapartum Amnioinfusion and Caesarean Rates
STUDY
AMNIOINFUSION
GROUP n (%)
ROUTINE
CARE
GROUP n (%)
ODDS RATIO
(95% CI)
Wenstroms and
Parsons
6/36(16.7)
15/29(34.1)
0.39(0.13,1.13)
Sandovsky et al
5/19(26.3)
7/21(33.3)
0.71(0.18,2.80)
Macri et al
13/85(15.3)
25/85(29.4)
0.43(0.2,0.92)
Spong et al
8/43(18.6)
9/50(18.0)
1.04(0.36,2.06)
Cialone et al
14/47(29.8)
11/58(19.0)
1.81(00.73,4.49)
Hofmeyr et al
70/167(41.9)
68/159(42.8)
0.97(0.62,1.50)
Mohomed et al
30/317(9.5)
37/328(11.3)
0.82(0.49,1.37)
Erikson et al
16/65(25.6)
14/59(23.7)
1.05(0.46,2.39)
Moodley et al
3/30(10.0)
7/30(23)
0.37(0.08,1.58)
Khosla et al
1/25(4.0)
7/25(28.0)
0.11(0.01,0.95)
TABLE–4: Intrapartum Amnioinfusion and Presence of
Meconium below vocal cord
STUDY
AMNIOINFUSION
GROUP n (%)
ROUTINE CARE
GROUP n (%)
ODDS RATIO
(95%CI)
Wenstrom and
Parsons
2/36(5.6)
16/44(34.4)
0.10(0.02,0.49)
Sandovsky et al
0/19(0.0)
6/21(28.6)
0.06(0.00,1.17)
Macri et al
4/85(4.7)
33/85(38)
0.08(0.03,0.23)
Spong et al
3/43(7.0)
2/50(4.0)
1.80(0.29,11.1)
Hofmeyr et al
6/158(3.8)
12/164(7.3)
0.48(0.11,2.1)
Erikson et al
1/65(1.5)
8/59(13.6)
0.10(0.01,0.82)
Khosla et al
3/25(12.0)
4/25(16.0)
0.72(0.14,3.59)
TABLE-5: Intrapartum Amnioinfusion and Meconium aspiration
Syndrome
STUDY
AMNIOINFUSION
GROUP n (%)
ROUTINE CARE
GROUP n(%)
ODDS RATIO
(95%CI)
Wenstrom and
Parsons
0/36(0.0)
3/44(6.8)
0.16(0.01,3.25)
Sandovsky et al
0/19(0.0)
0/21(0.0)
0.00(0.00,0.00)
Macri et al
0/85(0.0)
5/85(5.9)
0.09(0.00,1.57)
Spong et al
3/43(7.0)
1/50(2.0)
3.67(0.37,36.1)
Hofmeyr et al
4/162(2.5)
6/163(3.8)
0.66(0.18,2.39)
Mohomed et al
10/323(3.1)
42/329(12.8)
0.22(0.2,2.19)
Khosla et al
0/25(0.0)
1/25(4.0)
0.31(0.01,7.92)
MATERIALS & METHODS
This study entitled “ROLE OF INTRAPARTUM TRANSCERVICAL
AMNIOINFUSION IN MECONIUM STAINED AMNIOTIC FLUID AND NEONATAL OUTCOME” was
conducted in the Department of Obstetrics & Gynaecology, Darbhanga Medical
College & Hospital, Laheriasarai, Bihar.
STUDY AREA- Department of Obstetrics & Gynaecology,
Darbhanga Medical College & Hospital.
STUDY POPULATION- Labour
cases attending our Obstetric emergency after 37 weeks of pregnancy who exhibit
meconium stained liquor after spontaneous or artificial rupture of membranes.
STUDY PERIOD-
From 1st March 2015 to 31st
August 2016 –for
a period of one year and half years.
SAMPLE SIZE-
Total 100 cases (meconium
stained-50 & without meconium stained-50) were taken into consideration
depending upon inclusion and exclusion criteria.
SAMPLE DESIGN-
All consecutive cases where
interventions done were included according to the study criteria.
INCLUSION CRITERIA: -
(a) All pregnant patient at or after 37 weeks
with meconium stained liquor.
(b) Singleton
pregnancy.
(c) Cephalic presentation.
EXCLUSION CRITERIA: -
(a) Malpresentation
(b) Multiple
gestations
(c) Cord
Prolapse
(d) Ante partum
haemorrhage
(e) Chorioamnionitis
(f) Foetal
congenital anomaly
(g) Polyhydramnios
(h) Maternal
cardiovascular / respiratory disease
(i) Severe
foetal bradycardia
STUDY TOOLS-
(1) 100 women
in labour with meconium stained liquor were randomised to receive either
transcervical amnioinfusion (50) or routine
obstetric care.
(2) Clinical history,
physical examinations, and abdominal and vaginal examinations findings.
(3) Size-8 rubber
catheter with 2.5 mm in outer diameter.
(4) Normal saline
bottles, infusion set, moist oxygen.
(5) Monitoring of
FHR by intermittent auscultation with a stethoscope (every 20-30 minutes, and
between and at the end of contraction.)
(6) Uterine tone and
frequency of uterine contractions were assessed by palpation.
(7) Monitoring of
labour by partogram.
(8) Pre-designed
format for data collection.
(9) Various
statistical chart and analytical software.
STUDY DESIGN- Prospective Randomised Controlled Study.
PARAMETERS TO BE STUDIED-
(a) Mode of
delivery and operative intervention rates.
(b) Respiratory
distress
(c) Assessment
of APGAR score.
(d) SNCU
admission rate.
(e) Meconium
Aspiration Syndrome as diagnosed by X-ray.
(f) Meconium
below vocal cords.
(g) Perinatal
mortality rate.
(h) Post-partum
complications in the mother.
STUDY TECHNIQUE-
Hundred women at term in early labour with meconium stained
amniotic fluid were randomized to receive either Transcervical Intrapartum
amnioinfusion with saline (50) or routine obstetrical care (50). The selection
criteria for all patients was similar i.e., a singleton gestation, vertex
presentation, gestational age ≥37 weeks and cervical dilatation <5 cm, and
an adequate pelvis.
Following an informed written consent all the patients were
given a single dose of broad-spectrum antibiotic intravenously. A 8 -size red
rubber tube was introduced between foetal head and dilating cervix in to
amniotic cavity and 500 ml of normal saline was infused over 30 min, this is
followed by continuous infusion of normal saline at 3 ml per min. The foetal
heart rate and uterine tone were assessed continuously during the intervention.
If the uterine tone was persistently elevated, the infusion was discontinued
and the uterine pressure was allowed to equilibrate over five minutes. Resting
uterine tone was reassessed by palpation. Throughout the procedure----
- Continuous
monitoring of foetal heart rate was done
- Patient
was monitored for pulse /blood-pressure /temperature every 30 min
- Mother and
neonate were followed for 5-7 days postnatally.
Caesarean sections were carried out in either group if
foetal distress persists.
All neonates were managed by standard protocol of immediate
oropharangeal suction followed by endotracheal suction. During foetal
oropharyngeal suction, the presence of meconium below the vocal cords was
documented. Admission to the nursery and complications, including mortality,
were noted. An X-ray chest of babies with MAS was done.
ANALYSIS OF DATA-
Sample size calculation was done by using StatCalc 7.00
(Acastat software, Leesburg). Collected
data was plotted in various pie-charts,
histogram, chi-square table for graphical representation. Finally data found
analysed with statistical software Medcalc11.3.0. Proportion were analysed by
using chi-square test.
The differences were expressed considered to be
statistically significant with P <0.05 at 95% CI.
RESULTS & ANALYSIS
TABLE-6: DISTRIBUTION OF TOTAL PATIENTS
ACCORDING TO MATERNAL AGE:
AGE
(YEARS)
ROUTINE CARE GROUP
(n=50)
AMNIO-INFUSION
GROUP
(n=50)
P VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
≤20
6 (12)
5 (10)
0.861
0.749
0.0862
21-25
24 (48)
21 (42)
26-30
15 (30)
17 (34)
>30
5 (10)
7 (14)
In this study, total 100 patients were taken into
consideration, among which 50 had undergone amnioinfusion and another 50
received routine care.
Maximum patients were of 21-25 yrs of age =45.
There was no significant difference between study and
control group according to
maternal age because the differences found significant were not statistically
as the p value was >0.05.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO MATERNAL AGE.
TABLE-7: DISTRIBUTION
OF TOTAL PATIENTS
ACCORDING TO GESTATIONAL AGE.
GESTATIONAL AGE(WEEKS)
ROUTINE CARE
GROUP (n=50)
AMNIOINFUSION
GROUP (n=50)
P VALUE
<38
8(16)
8(16)
0.8026
(NS)
38-39
9(18)
22(44)
0.0611
(NS)
39-40
28(56)
15(30)
0.0673
(NS)
>40
5(10)
5(10)
0.7518
(NS)
There was no significant difference between study and
control group according to gestational age.
Increased incidence of MSAF is noted in gestational age
>39 wks.
Large group of cases belong to gestational age 39-40 wks.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO GESTATIONAL AGE.
TABLE-8: DISTRIBUTION
OF TOTAL PATIENTS
ACCORDING TO PARITY.
ROUTINE CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
Primi
28 (56)
22 (44)
0.317
1.000
0.099
Multi
22 (44)
28 (56)
In the amnioinfusion group, 22(44%) were primigravida &
28(56%) were multigravida. In the control group patients, 28(56%) were
primigravida &22(44%) were multigravida.
There was no significant difference between study and
control group according to parity because the differences found were not
statistically significant as the p value was>0.05.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO PARITY.
TABLE-9: DISTRIBUTION
OF PATIENTS ACCORDING
TO
RISK FACTORS.
RISK-FACTORS
ROUTINE CARE
GROUP (n=50)
AMNIOINFUSION
GROUP
(n=50)
P VALUE
Pre-eclampsia
11 (22)
7 (14)
0.479
(NS)
Post-dated
16 (32)
10 (20)
0.326
(NS)
Previous LSCS
5 (10)
5 (10)
0.751
(NS)
Anaemia
6 (12)
5 (10)
1.000
(NS)
In this study, it is clear from the above chart that;
incidence of MSAF is more in pre-eclampsia & post-dated pregnancy (18%
& 26% respectively).
No significant statistical difference between study and
control group was seen according to the mentioned risk factors.
DISTRIBUTION OF PATIENTS ACCORDING TO RISK FACTORS.
TABLE-10:
DISTRIBUTION OF TOTAL PATIENTS
ACCORDING TO LABOUR
CHARACTERISTICS:
ONSET OF
LABOUR
ROUTINE
CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
Spontaneous
33 (66)
30 (60)
0.678
0.172
0.0414
Induced/
Augmented
17 (34)
20 (40)
Among the study group, 30(60%) went into spontaneous labour
& 20(40%) into induced/augmented labour. Whereas in the control group,
33(66%) into spontaneous labour & 17(34%) into induced/augmented labour.
The differences found between these two groups were not
statistically significant as the p value was >0.05.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO LABOUR
CHARACTERISTICS.
TABLE-11: DISTRIBUTION OF TOTAL PATIENTS
ACCORDING TO MODE OF DELIVERY.
MODE OF
DELIVERY
ROUTINE
CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
FTND
27 (54)
40 (80)
0.0103
9.159
0.290
FORCEPS
DELIVERY
6 (12)
5 (10)
CAESAREAN
DELIVERY
17 (34)
5 (10)
In the amnioinfusion group, 40 patients (80%) had FTND as
compared to only 27(54%) patients of control group patients.
The incidence of Forceps delivery was almost same in the
study group (10%) and control group (12%).
The incidence of Caesarean section rate was 10% in the study
group as compared to 34% in control group.
Statistically significant difference was there as p value was <0.05.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO MODE OF
DELIVERY.
TABLE-12:
DISTRIBUTION OF TOTAL PATIENTS
ACCORDING TO SEX OF THE BABY:
SEX OF
THE
BABY
ROUTINE CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
Boy
27 (54)
30 (60)
0.686
0.163
0.040
Girl
23 (46)
20 (40)
In the study group, 30(60%) patients delivered boy babies
and another 20(40%) patients delivered girl babies. In the control group,
27(54%) patients delivered boy babies and another 23(46%) patients delivered
girl babies.
No significant differences between study and control group
were found as the p value was >0.05.
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO SEX OF BABIES.
TABLE-13: COMPARATIVE
EVALUATION OF
NEONATAL APGAR SCORE AT 1 MIN:
APGAR SCORE
AT 1 MIN
ROUTINE
CARE GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
≤6
25(50)
10 (20)
0.0033
8.615
0.282
>6
25 (50)
40 (80)
Number of cases with APGAR @ 1 min, ≤6 were 10(20%) in the
study group as compared to 25(50%) in control group.
Number of cases with APGAR @ 1 min, >6 were 40(80%) in
the study group as compared to 25(50%) in control group.
There was a significant improvement of APGAR score @ 1 min,
which was statistically significant (p<0.05).
COMPARATIVE EVALUATION OF NEONATAL APGAR SCORE @ 1 MIN.
TABLE-14: COMPARATIVE
EVALUATION OF
NEONATAL APGAR SCORE AT 5 MIN:
APGAR
SCORE
AT 5 MIN
ROUTINE
CARE GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
≤6
2 (4)
1 (2)
1.000
0.000
0.000
>6
48 (96)
49 (98)
Number of cases with APGAR @ 5 min, ≤6 were 1(2%) in the
study group as compared to 2(4%) in control group.
Number of cases with APGAR @5 min, >6 were 49(98%) in
amnioinfusion group
There was no significant improvement of APGAR score @5 min
In amnioinfusion group.
The difference found was statistically not significant
(p>0.05).
COMPARATIVE EVALUATION OF NEONATAL APGAR SCORE @ 5 MIN.
TABLE-15:
DISTRIBUTION OF TOTAL PATIENTS
ACCORDING TO BIRTH WEIGHT OF BABIES
WEIGHT
(in kg)
ROUTINE
CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P
VALUE
X2
VALUE
CONTIGENCY
COEFFICIENT
<2.5
10 (20)
3 (6)
0.1344
5.573
0.230
2.5-3
20 (40)
19 (38)
3-3.5
14 (28)
22 (44)
>3.5
6 (12)
6 (12)
There was no significant difference between the study and
control group In relation to birth weight of babies (p>0.05).
DISTRIBUTION OF TOTAL PATIENTS ACCORDING TO BIRTH WEIGHT OF
BABIES.
TABLE-16: COMPARATIVE
EVALUATION
OF
NEONATAL OUTCOME:
NEONATAL
OUTCOME
ROUTINE CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
P VALUE
Respiratory distress
25 (50)
8 (16)
0.0053
MAS
10 (20)
2 (4)
0.0433
Meconium below vocal cord
21 (42)
6 (12)
0.0071
SNCU admission
14 (28)
3 (6)
0.0153
Perinatal mortality
1 (2)
Nil
NS
Respiratory distress was markedly reduced in amnioinfusion
group 8(16%) as compared to
25(50%) in controls (p=0.0053).
MAS was markedly reduced by amnioinfusion. It occurred in
2(4%) in the study group &
10(20%) in the control group (p=0.0433).
Meconium below vocal cord was evident in only 6(12%)
patients in the study group,
compared to 21(42%) in the control group (p=0.0071).
SNCU admission were 14(28%) in the control group compared
to 3(6%) in the study group
(p=0.0153).
Perinatal mortality was nil in the study group as compared
to 1(2%) in the control group
(statistically not significant). So neonatal outcome was significantly better
in the study group.
COMPARATIVE EVALUATION OF NEONATAL OUTCOME.
TABLE-17: COMPARATIVE
EVALUATION OF
MATERNAL COMPLICATIONS:
MATERNAL
COMPLICATIONS
ROUTINE CARE
GROUP
(n=50)
AMNIOINFUSION
GROUP
(n=50)
Puerperal pyrexia
1
1
Hypertonic uterus
Nil
Nil
Scar rupture
Nil
Nil
Maternal complications in both amnioinfusion group and study
group were same. There was no increased incidence of maternal complications
because of the procedure.
DISCUSSION
Although Intrapartum Amnioinfusion was introduced more than
2 decades ago, reports of its regular use in developing countries are scarce.
This is due to the lack of specially designed intrauterine catheter &
equipment for electronic foetal monitoring. The findings of the present study
are that-amnioinfusion is a safe, technically feasible and easily affordable
procedure in a rural set-up where most of the patients are of lower
socio-economic status.
As the participants were from same area and similar
backgrounds, the study and control groups were balanced with respect to
socio-demographic variables & baseline obstetric characteristics.
In this study there was no significant difference between
study group and control group according to age, parity, gestational age,
hypertension/pre-eclampsia, post-dated pregnancy, anaemia, onset of labour, sex
and birth weight of babies.
James mentions incidence of MSAF increases with gestational
age and reaches approximately 30% at 40 weeks and 50% at 42 weeks. High
incidence of MSAF was noted in high risk pregnancy in our study. Similarly one
study noted increased incidence of MSAF is more in HTN/pre-eclampsia and
post-dated pregnancy.
Sandu et al noted majority (80%) of cases with MSAF belonged
to the age group of 21-30 years. In our study 77% of cases with MSAF belong to
the same age group.
In this study, there was a trend towards lower caesarean
delivery rate in the amnioinfusion group. The incidence of caesarean section
rate was 10% in the study group as compared to 34% in control
group(p<0.05).The probable
explanation for the lower caesarean section rate in the study group is that by
increasing the amniotic fluid volume around the fetus, amnioinfusion reduces the
risk of foetal distress caused by umbilical cord compression. In the study
group, 80% (40/50) patients had a vaginal delivery as compared to only 54 %(
27/50) of control group patients (p< 0.05). The incidence of Forceps
delivery was almost same in study group (10%) and control group (12%).
Study by Macri et al showed that the rate of caesarean
section was significantly reduced in amnioinfusion group. Wenstrom et al: also
showed that patients receiving amnioinfusion had significantly lower incidence
of operative delivery.
There was no significant difference between study group and
control according to sex and birth weight of fetus (P>0.05). Number of cases
with APGAR @ 1 min, ≤6 were 20% (10/50) in study group as compared to 50 %(
25/50) in control group. There was significant improvement in APGAR score @ 1
min (P = 0.0033) in amnioinfusion group, suggesting a lesser need for immediate
neonatal intervention, for which equipments and trained personnel are often
lacking developing countries. This study correlated with CRAMP -I study which
showed improvement in 1min APGAR. In this study number of cases with APGAR @ 5
min, ≤6 were 2/50 (4%) in control group as compared to 1/50 (2%) in study
group. In our study there was no significant improvement in 5 min APGAR (P =
1).
However CRAMP-2, meta analysis study shows significant
reduction in incidence of 5 min APGAR < 7.
Meconium below the vocal cords was evident in only 12%
(6/50) patients receiving amnioinfusion, compared to 42 %( 21/50) in the
non-infusion group of patients (P=0.0071). Meconium aspiration syndrome was
reduced markedly in amnioinfusion group. It occurred in 4% of cases in the
study group and 20% of cases in the control group (p=0.0433). Fewer cases of
MAS & meconium below vocal cord would reduce the burden of complications in
developing countries with poor resources. Respiratory distress was markedly
reduced in amnioinfusion group 8(16%) compared to 25(50%) in controls.
(P=0.0053). SNCU admissions were 14(28%) in control group compared to3 (6%) in
amnioinfused group (P=0.0153). Perinatal mortality in the study group was nil
as compared to 2% in the control group (statistically not significant).
Many studies have shown decreased incidence of foetal
distress, operative delivery (Table-3), meconium below vocal cord (Table-4), meconium aspiration syndrome
(Table-5) and without much increase in
maternal complications (Table-6).
CRAMP-1 and CRAMP-2 meta-analysis study shows significant
reduction in several measures of perinatal morbidity in amnioinfused group:
meconium aspiration syndrome, NICU admission, and 5min APGAR score.
In this study 10cases of MAS occurred in control group and 2
in amnioinfusion group. .Macri et al noted the rate of caesarean section;
meconium aspiration and meconium aspiration syndrome were significantly reduced
in amnioinfusion group. A study by Wenstrom et al showed that patients
receiving amnioinfusion had significantly fewer 1 min APGAR score, less
meconium below vocal cords and a significantly lower incidence of operative delivery.
In this study, complications in both Amnioinfusion and study
group were same. There was no increased incidence of fever/ endometritis
because of the Procedure. Wenstrom et al 41 stated that neither the method
employed nor the number of infusions performed appears to significantly
increase the risk of complication. CRAMP-2, Meta study shows no significant
increase in maternal complication because of the procedure.
Although an accurate cost-benefit analysis of amnioinfusion
is difficult, the possible cost savings are enormous. The average cost of a
caesarean section is about 50-100 times more than that of an amnioinfusion in a
same set-up. In addition, shorter hospital stay reduces the cost of childbirth
where health resources are overstretched. Furthermore emergency caesarean
section can have serious consequences on maternal health, especially if the
operation is performed in a suboptimal condition in an under-resourced
facility.
SUMMARY & CONCLUSIONS
This study was carried out in the Departments of Obstetrics
and Gynaecology, DMCH, Laheriasarai, between March 2015 to August 2016. A total
of 100 cases with intrapartum passage of meconium were selected and a
prospective randomized study was carried out.
Patients with meconium stained amniotic fluid were selected
randomly. The study group (50) comprised patients who received Amnioinfusion;
the control group (50) received routine obstetric care for meconium. There was no significant difference between
study group and control according to age, parity, and gestational age,
HTN/pre-Eclampsia, post-dated pregnancy, anaemia.
There was no significant difference between study group and
control whether membranes were ruptured spontaneously or induced. Transcervical amnioinfusion is effective in
improving both maternal and perinatal outcome by the fact that-
(a) It
increases the chances of normal delivery. There is significant increased
incidence of normal delivery (80%) in
the study group as compared to (54%) control group (p<0.05).
(b) Significant
reduction in caesarean rates from 34% to 10% (p<0.05).
(c) Significant
improvement in APGAR @ 1min (p=0.0033).
(d) Significant
decrease in the incidence of respiratory distress (p=0.0053), meconium below vocal
cord (p=0.0071), meconium aspiration syndrome (p=0.0433) and SNCU admission.
(p=0.0153).
(e) Perinatal
mortality was nil in the study group as compared to 1(2%) in the control group,
though statistically not significant.
(f) There was
no increased incidence of any maternal complications.
Intrapartum Transcervical Amnioinfusion for MSAF is a
simple, safe and Inexpensive intervention. It is effective in reduction of
operative intervention rates and MAS in the set-up not equipped for electronic
foetal monitoring and specialised neonatal care. This implies that a lack of
modern facilities for peripartum care should not deter one from using
amnioinfusion in the presence of MSAF. This study suggests that substantial
benefits can arise from performing amnioinfusion in most of the district
hospitals in developing countries.
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DATA COLLECTION FORMAT
DATA COLLECTION FORMAT:
PATIENT PARTICULARS-
(a) Name
(b) Age
(c) Registration
No.
(d) Name of the
husband
(e) Address
(f) Occupation of
the husband
(g) Occupation of
the wife
(h) Unit
concerned
MENSTRUAL HISTORY-
(a) Menarche
(b) Cycle
(c) Duration
(d) LMP
(e) EDD
PAST MEDICAL/SURGICAL HISTORY-
PERSONAL HISTORY/DRUG HISTORY-
FAMILY HISTORY-
PAST OBSTETRIC HISTORY-
No
Year &
Date
Pregnancy
events
Labour
events
Delivery
methods
Perinatal
outcome
ABOUT CURRENT PREGNANCY-
Booked/unbooked
No of
ANC
Referred or not
Stage
of labour
Investigations report
GENERAL EXAMINATION-
Height Oedema
Pallor
Cyanosis
Pulse Neck
vein/gland
BP Respiration
Jaundice
SYSTEMIC EXAMINATION-
Fundal
height Lie
Presentation FHS
P/V EXAMINATION-
OS-
Presentation
Membranes
ruptured at-
Spontaneous/induced
Meconium-thick/moderate/thin.
AMNIOINFUSION:-
Given
at…../not given.
Oxytocin used/ not used. If used …..units.
Any other drug used/ not.
Antibiotic used…………..
MODE OF DELIVERY:
Spontaneous/ vaginal.
Forceps/LSCS. (If LSCS, indication)
Timing of
delivery.
NEONATAL OUTCOME:
Apgar @ 1
min
Apgar @5
min
Birth
weight
Respiratory distress………
Yes/No.
Meconium aspiration syndrome….Yes/No.
SNCU admission………………….Yes/No.
Perinatal mortality…………………Yes/No.
MATERNAL OUTCOME:
Any
maternal complication……………….
ABBREVIATIONS
AI - AMNIOINFUSION.
AF - AMNIOTIC FLUID
AFI - AMNIOTIC FLUID INDEX
ARM - ARTIFICIAL RUPTURE OF MEMBRANES
BP - BLOOD PRESSURE
CRAMP - Collaborative Randomised Amnioinfusion for Meconium
Project
CI - CONFIDENTIAL INTERVAL
ECMO - EXTRACORPOREAL MEMBRANE OXYGENATION
FHR - FETAL HEART RATE
MAS - MECONIUM ASPIRATION SYNDROME
MSAF - MECONIUM STAINED AMNIOTIC FLUID
n – NUMBER
SNCU – SICK NEWBORN CARE UNIT
OR – ODDS RATIO
PROM - PREMATURE RUPTURE OF MEMBRANE
rpm - REVOLUTIONS PER MIN
RR - RELATIVE RISK
VBAC - VAGINAL BIRTH AFTER CAESAREAN
Vs – VERSUS
Wk – WEEK
% - PERCENTAGE
