Differences in meconium stained amniotic fluid in an Australian population: A retrospective study

Abstract

BackgroundMeconium stained amniotic fluid commonly occurs postdates ( >40 weeks gestation) indicating fetal maturity. Previous literature indicates that different ethnicities mature at different rates. AimTo compare the rate of meconium stained amniotic fluid of Australian-born and non-Australian born women. MethodsA retrospective correlation study design was implemented, using data collected in the birth outcomes system at one tertiary hospital. Data was collected from all women who gave birth to a term (>/=37 weeks gestation), singleton, liveborn baby between January 1st to December 31st, 2014. Maternal country of birth was used for comparison. Categorical data was analyzed using Chi-Square test for Independence. Continuous variables were assessed for normality, and differences were compared using an Independent t-test or a Mann–Whitney U test. All tests were two-tailed and p<0.05 was considered statistically significant. Results3,041 women were included; 1131 Australian-born and 1910 non-Australian born. Meconium stained amniotic fluid occurred more frequently in non-Australian born women compared to Australian-born women (23.5% vs. 19.8 p=0.02). Their babies were significantly smaller (Mean=3265g, Standard Deviation 463.8 vs Mean=3442g, Standard Deviation 499.2, p<0.001), with no difference in gestational length (Mean=39.4, Standard Deviation 1.28 vs Mean=39.5, Standard Deviation 1.18, p=0.06). Increasing gestational age had the strongest association with meconium stained amniotic fluid; >/=42 weeks gestation occurring 3.52 (95% Confidence Interval: 2.00, 6.22, p=<0.001) more than <40 weeks gestation. ConclusionMaternity health services should record ethnicity and region of birth to provide individualised care as women born overseas often have poorer perinatal outcomes when compared to Australian-born women.