Maternal ethnic group and pregnancy anthropometrics in the development of maternal and infant health outcomes

Abstract

Aim: To investigate associations between pregnancy outcomes, South Asian ethnicity and pre-/early-pregnancy maternal anthropometrics (MA) and gestational anthropometric change (GAC). Methods: A mixed methods approach was used to develop an evidence-based conceptual model of associations between outcomes and MA/GAC, involving: a systematic review, a framework-based synthesis and expert opinion. The conceptual model was tested using the Born in Bradford cohort data for Pakistani and White women. Regression models were used to investigate associations, adjusting for socio-demographic, behavioural and clinical factors. Results: The evidence-based conceptual model hypothesised that gestational diabetes (GDM), hypertensive disorders of pregnancy (HDP), mode of delivery, maternal mortality, birth weight, gestational age at delivery, stillbirth, perinatal mortality, post-partum IGT, PPWR, breastfeeding, infant anthropometrics and maternal and child blood pressure in the longer term were associated with MA and GAC. Pakistani women had significantly increased odds of GDM (Adjusted odds ratio (AOR) 1.08 (95%CI 1.06-1.11), HDP (AOR 1.11 (95%CI 1.08-1.15), Cesarean-section (AOR 1.05 (95%CI 1.01-1.08)), and induction (AOR 1.07 (95%CI 1.05-1.09)), and increased birth weight (adjusted coefficients; 13.77g (95%CI 9.24-18.30) associated with increasing BMI. With increasing GWG, birth weight increased for Pakistani women (adjusted coefficients; 22.92g (95%CI 18.07-27.78)). Significant interactions were identified for BMI and ethnicity on GDM (p=0.045), pre-term birth (p=0.049) following adjustment. There were no significant interactions between GWG and ethnicity on other pregnancy outcomes following adjustment. This was also true when using Asian-specific BMI criteria to calculate GWG. Conclusion: There were ethnic differences in the shape of the association between BMI and GDM, and pre-term birth, following adjustment. In this cohort, there was no evidence of an ethnic difference in the association between any pregnancy outcome investigated and GWG following adjustment. More research is needed to investigate additional measures of GAC, and using other datasets looking at all South Asian subgroups.