Supriya Mahajan1, Laul2
OBJECTIVES: Postdate pregnancy is the most common indication for Antepartum. Fetal heart rate testing because of its increased perinatal morbidity and perinatal mortality. Complications are stillbirth, meconium aspiration, asphyxia, and the dysmaturity syndrome, is increased in post-term pregnancies. The most recent ACOG review of the subject of "post-term" pregnancy cites estimates of 3-14% of all pregnancies.
MATERIALS AND METHODS: 55 patients with pregnancy beyond 40 weeks attending antenatal out-patient department of the Rajiv Gandhi medical college in the period between October 2014 to March 2015 were included. In present study, patients were monitored with twice weekly NST and once a week Doppler. In those with either NST nonreactive or Doppler abnormal, induction was done. Cases with normal results were monitored till 42 weeks when routine induction was done.
RESULTS: A reactive non stress test in prolonged pregnancy has good negative predictive value – i.e. adverse outcomes are unlikely to occur in the setting of a reactive non-stress test – but that the positive predictive values are low. Weekly measurement of Doppler waveforms from umbilical artery (PI p=0.02 for Apgar <7 at 5 min, p=0.02 NICU admissions, p=0.003 for meconium staining of amniotic fluid and S/d ratio p=0.02 for Apgar <7 at 5 min, p=0.04 for NICU admission) and biweekly NST(p=0.005 for Apgar <7 at 5 min, p=0.0219 for NICU admission, p=0.0039 for meconium staining of amniotic fluid) appears to be reliable method of establishing fetal health in pregnancy beyond 40 weeks.
CONCLUSION: The most sensitive tests to assess the risks to the fetus of prolonged pregnancy appear to be combinations of fetal heart rate monitoring with NST combined with umbilical PI and S/D ratio. Reactive NST is reassuring and indicates fetal wellbeing, but non-reactive NST alone cannot be taken as an indicator of fetal jeopardy. Although individual randomized trials do not show significant differences in perinatal mortality between women electively induced at specific gestational ages and women followed with antepartum testing, data shows significant increase in abnormal fetal outcome after 41 weeks.