Introduction
Meconium is the first feces of a newborn that is stored in the baby's intestine until birth. Although it is different from regular stool because it doesn't have any bacteria or odor, it can cause problem if a baby inhales the meconium while in the uterus, when it mixed with amniotic fluid, or just after they are born. When this occurs, it is called meconium aspiration. This happens in babies born on time and born post-term after 42 weeks as opposed to premature infants.
Newborn in mother with thick (amniotic fluid looks like pea soup) or thin (watery) meconium staining liquor (MSL) can aspirate into lungs and develop respiratory distress. Respiratory distress develops within 24 hour of life. This is known as meconium aspiration syndrome (MAS).
Meconium Particles in the amniotic fluid can block small airways and prevent a baby from breathing properly causing respiratory distress. This meconium aspiration can occur either during labour or at the time of baby's first breath.
The aspirated meconium causes acute airways obstruction, scattered atelectasis with ventilation perfusion mismatch, hyper-expansion. The obstructive phases followed by an inflammatory phase 17-24 hours and progress to pulmonary hypertension and respiratory failure. Further more some babies with meconium aspiration go on as to develop a condition called pulmonary hypertension. Pulmonary hypertension decreases the flow of blood into the lungs, where it normally picks up oxygen. Instead, blood by passes the lungs, and very little oxygen gets to the baby. The condition often improves within a few days, although severe meconium aspiration and pulmonary hypertension may be fatal in a very small percentage of babies.
Objective
To observe the risk factors of:
- Intra uterine passage of meconium
- Meconium aspiration syndrome and its morbidity and mortality pattern.
Design – Prospective study
Setting – Hospital Based study
Methods
Cases selected were those babies delivered through meconium stained amniotic fluid either vaginally or cesarean section.
Maternal data regarding age, parity, socio-economic status, antenatal, obstetrical problems were recorded.
With the delivery of head of the baby, a thorough intra partum suctioning was done, first of the oropharynx and then of the nasopharynx by the obstetrician or by the pediatrician. The baby was then transferred to resuscitation table.
After drying the baby, the larynx was visualized and if meconium was seen at the level of vocal cords the baby was intubated and meconium was sucked out, while withdrawing the endotracheal tube. The suction was done using mechanical suction. This procedure was repeated 2 or 3 times till clear aspiration.
Babies showing sign of respiratory distress were admitted to the neonatal unit for further observation, investigation (radiological and others), treatment, mortality and morbidity pattern and follow-up.
Results
Total 1000 deliveries were studied.
Incidence of meconium stained amniotic fluid babies was 10% of the deliveries.
Meconium aspiration syndrome was found in 25% cases of meconium stained amniotic fluid and 25% of total deliveries.
Incidence of meconium aspiration syndrome was highest in thick meconium 80% and lowest in the thin meconium i.e., 6.6%.
Higher incidence of meconium aspiration syndrome was also associated with cesarean section 80% in comparison to vaginal delivery 20%.
Increased gestational age was associated with higher incidence of meconium aspiration syndrome.
Average birth weight of babies with meconium aspiration syndrome was less then 3 kg.
Mortality was highest in thick meconium (specially if it was below the level of vHocal cord) 25%, in comparison to thin meconium 6.6%.
Highest mortality was also associated with low APGAR SCORE at 1 minute.
Conclusion
- Increased incidence of meconium aspiration syndrome was associated with
- Increase in the gestational age
- When the meconium was thick
- In cesarean delivery
- Highest mortality was associated with thick meconium when it was present below the vocal cord and low APGAR SCORE at 1 minute.
- Prognosis was excellent when meconium was thin and above the level of vocal cord.
Hence proper diagnosis and timely interventions can reduce the mortality and morbidity in meconium aspiration syndrome.
