Post-term surveillance and birth outcomes in South Asian-born compared with Australian-born women

To determine if apparently healthy post-term South Asian-born (SA) women were more likely to have abnormal post-term fetal surveillance than Australian- and New Zealand-born (AUS/NZ) women, whether those abnormalities were associated with increased rates of obstetric intervention and adverse perinatal outcomes, and whether SA women and their babies were at higher risk of adverse outcomes in the post-term period irrespective of their post-term surveillance outcomes.

Post-term surveillance and perinatal outcomes of 145 SA and 272 AUS/NZ nulliparous women with a singleton post-term pregnancy were compared in a retrospective multicentre cohort analysis.

Post-term SA women were not significantly more likely to have a low amniotic fluid index (AFI) than AUS/NZ women. However, they were nearly four times more likely (odds ratio 3.75; 95% CI 1.49-9.44) to have an abnormal CTG (P=0.005). Irrespective of maternal region of birth having an abnormal cardiotocography (CTG) or AFI was not associated with adverse intrapartum or perinatal outcomes. However, post-term SA women were significantly more likely than AUS/NZ women to have intrapartum fetal compromise (P=0.03) and an intrapartum cesarean section (P=0.002). Babies of SA women were more also significantly likely to be admitted to the Special Care Nursery or Neonatal Intensive Care Unit (P=0.02).

Post-term SA women experience higher rates of fetal compromise (antenatal and intrapartum) and obstetric intervention than AUS/NZ women. Irrespective of maternal region of birth an abnormal CTG or AFI was not predictive of adverse outcomes.