Meconium Staining of Amniotic Fluid- A Poor Indicator of Fetal Compromise

The classical concept of passage of meconium by the fetus in response to hypoxia and its association with poor fetal outcome is controversial. However, conventionally, the passage of meconium by the fetus has been taken as an indication for urgent delivery. Although its exact cause is not known, factors ranging from mesenteric vasoconstriction induced gut hyperperistalsis, falling umbilical venous saturation, vagal stimulation and a normal physiological function of a mature fetus have all been proposed to have an aetiological role in this condition (1,2). Conflicting outcomes have been reported in the labours complicated by meconium staining of the amniotic fluid, varying with the degree of meconium staining (3-5) Although Abramovici et al failed to demonstrate a correlation between the appearance of meconium during labour and fetal outcome , Low and Paul et al suggested a significant increase in fetal asphyxia with meconium staining of amniotic fluid (3-5) With facilities like continuous fetal heart rate monitoring and scalp pH estimations, the degree of fetal compromise can be evaluated. In the present prospective studY, fetal heart rate abnormalities, mode of delivery and short term fetal outcome have been evaluated in relation to different degrees of meconium staining and to a control population, with the aim to evaluate the accuracy of meconium staining of amniotic fluid as a marker of fetal compromise. Material and Methods The present prospective study was carried out over a 3 month period on 100 consecutive cases admitted to the labour ward of a tertiary care centre of North India, with singleton term pregnancies, cephalic presentation and various degrees of meconium staining of amniotic fluid during labour. One thousand one hundred and sixty seven other patients with clear amniotic fluid during labour and who were matched for age, parity, period of gestation and blood pressure, were regarded as controls. Women with previous cesarean sections and breech presentations were not included in the study. All the patients in the study were subjected to a standardized form of management. All patients underwent a full trial of vaginal delivery and cesarean section was carried out only if vaginal delivery was unsuccessful or if fetal distress developed. All women with meconium in the liquor were monitored by continuous Abstract The presence of meconium at the onset of labour and its obstetric outcome was studied over a 3 month period. Out of the 1267 deliveries that occurred during this period, 100 (7.89%) had meconium staining of liquor. These were compared to the remaining 1167 patients with clear liquor. Monitoring included cardiotocography, scalp pH estimation when required and optimal care at delivery.The fetal heart rate abnormalities were more common in meconium stained patients. Thick meconium staining was associated with higher cesarean section rate, low Apgar score at one minute and more admissions to the neonatal intensive care unit.All women with meconium staining of liquor should be cardiotocographically monitored in labour and managed by optimal timely intervention in order to avoid severe asphyxia and meconium aspiration