Ramadan and gestational diabetes: maternal and neonatal outcomes

AIMS: The impact of Ramadan exposure to Gestational Diabetes Mellitus (GDM) pregnancies is not known. We therefore aimed to assess the association of Ramadan with maternal and neonatal outcomes among pregnant women with GDM. METHODS: Retrospective cohort study of 345 Muslim women with singleton pregnancies who attended a major Sydney teaching hospital during the period 1989–2010, was undertaken. Exposure to Ramadan was stratified by the: (1) total pregnancy days exposed to Ramadan, (2) duration (hours) of daily fasting and (3) trimester of exposure. Maternal and neonatal outcomes were examined by exposure status, and never exposed pregnancies were comparator in all three analyses. Fasting status was not recorded. RESULTS: We found no significant effect of Ramadan exposure on mean birthweight, macrosomia and maternal outcomes. However, we found a significant trend for increased neonatal hyperbilirubinemia with increasing Ramadan days exposure and later trimester exposure (p(trend) ≤ 0.02 for both), with adjusted OR 3.9 (p=0.03) for those with ≥ 21 days exposure to Ramadan and adjusted OR 4.3 (p=0.04) for third trimester exposure. Conversely longer Ramadan exposure and late trimester exposure were independently associated with a lower prevalence of neonatal hypoglycaemia (adjusted OR 0.4 and 0.3 for ≥ 21 days and third trimester exposure, respectively). Furthermore, neonatal hypoglycaemia decreased for the fasting period of > 15 h group (adjusted OR 0.2, p = 0.01). CONCLUSIONS: Ramadan exposure is associated with reduced neonatal hypoglycaemia, with no effect on birthweight, implying more favourable glycaemic control. However, the fourfold excess of neonatal hyperbilirubinemia indicates a need for further study of Ramadan and GDM. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00592-021-01782-y.