Poster Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2015

Is South Asian ethnicity a risk factor for adverse perinatal outcomes in the post-term period? (#108)

Cheryl Yim 1 , Lufee Wong 1 , Carlos Cabalag 1 , Euan Wallace 1 2 3 , Miranda Davies-Tuck 2
  1. Monash Women's, Monash Health, Clayton, Victoria, Australia
  2. The Ritchie Centre, Monash Institute of Medical Research, Clayton, Victoria, Australia
  3. Obstetrics & Gynaecology, Monash University, Clayton, Victoria, Australia

Introduction: Maternal ethnicity is an emerging risk factor for adverse perinatal outcomes. South Asian women in particular are 2.4 times more likely to have a late-pregnancy antepartum stillbirth than Australian-born women[1]. This may be related to inherent differences in gestation lengths between ethnicities, the underlying mechanisms of which remain unclear[2]. Our aim was to determine if otherwise healthy post-term South Asian-born(SA) women were more likely to demonstrate fetal compromise in late pregnancy than Australian- and New Zealand-born(ANZ) women during routine post-term fetal surveillance, and whether this correlated with perinatal outcomes.

Methods: For the period 2006-2012, pregnancy outcomes for all nulliparous singleton post-term (≥41 weeks and 3 days gestation) SA and ANZ women with available post-term surveillance records at Monash Health were compared. Outcomes included abnormal post-term surveillance (AFI or CTG), onset of labour, presence of intrapartum fetal compromise, mode of delivery and neonatal outcomes.

Results: The outcomes for 145 SA and 272 ANZ women and their babies were studied. SA women were more likely than ANZ women to have an abnormal CTG (10.3% v 3.3%%, p=0.004) during post-term surveillance, but not a lower AFI (p=0.11). SA women were also more likely to undergo an induction of labour (70.3% v 59.2%, p=0.02), demonstrate intrapartum fetal compromise (55.9% v 44.5%, p=0.02) and deliver by emergency Caesarean section (51.7% v 38.2%, p=0.008). There was a higher rate of neonatal intensive care unit (NICU) admission for SA babies (28.5% v 20.6%, p=0.047), but no differences in Apgar scores or cord lactates.

Conclusion: SA women are at higher risk of maternal and neonatal morbidity in the post-term period compared to ANZ women. Given the increasing proportion of overseas-born women receiving obstetric care in Australia, the possible ethnicity-related differences in perinatal outcomes warrant further study so that tailored improvements to care can be developed.

  1. Drysdale H, Ranasinha S, Kendall A, Knight M, Wallace EM. Ethnicity and the risk of late-pregnancy stillbirth. MJA. 2012 Sep 3;197(5):278-81.
  2. Patel RR, Steer P, Doyle P, Little MP, Elliott P. Does gestation vary by ethnic group? A London-based study of over 122,000 pregnancies with spontaneous onset of labour. Int J Epidemiol. 2004 Feb;33(1):107-13.
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