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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Post-term Pregnancy and Induction of Labor
Sponsored by The Indian Health Service Clinical Support Center
9 Intrapartum
Amnioinfusion
If thick meconium or severe repetitive variable decelerations complicate post-term labor, amnioinfusion is a helpful intervention. The evidence from Hofmeyr
in the Cochrane demonstrates that it significantly decreases the incidence of the meconium aspiration syndrome, and may decrease the need for cesarean delivery for fetal intolerance of labor.
After placing an intrauterine pressure catheter, amnioinfusion is begun by giving a bolus of 300 mL of room temperature Ringer’s lactate solution by gravity infusion or on a pump, and then continuing the infusion at 150 mL/hour. This will dilute and wash out the meconium, and hopefully restore sufficient volume to cushion or float the umbilical cord and protect it from the compression induced by uterine contractions.
Delivery
As noted above, fetal macrosomia is more common in post-dates pregnancy, so one should be prepared to deal with the possibility of shoulder dystocia at delivery.
Please note that the changes in obstetric practice and methods of fetal evaluation since the trial of Walker 1959 make it difficult to relate the results to contemporary obstetric practice for those working in situations without operative obstetric facilities.
Hofmeyr and Kulier,
in the Cochrane Library, show that the policy of operative delivery in the event of meconium-stained liquor or fetal heart rate changes causes a considerable increase in operative deliveries, and has not been shown to reduce perinatal mortality.
Intubation for meconium suctioning of the trachea should be reserved for depressed infants who have experienced abnormal fetal heart rate patterns in labor, not for the vigorous infant that is born through thick meconium who otherwise has had adequate suctioning on the perineum. (Nadkarni et al)
Monitoring for postnatal hypoglycemia is also a prudent precaution, and early feeding may be indicated.
