Risk factors of gestational diabetes mellitus: A hospital-based pair-matched case-control study in coastal South India

Background. In the light of the rise in prevalence of gestational diabetes mellitus (GDM) and the importance of early suspicion and prompt diagnosis, different regions have reported different risk factors. This warrants multiple regional studies in sub-populations and diverse geographic areas to quantify determinants of GDM. Objective. To determine risk factors of GDM. Methods. A case-control study was conducted in a tertiary care maternity hospital in coastal South India based on pregnancy records of all those women diagnosed with GDM who received in-patient care between January 2018 and December 2018. There were 131 cases pairmatched for age in the ratio of 1:1 with 131 controls. Results. Women from rural areas and those with a monthly income <= INR20 000, body mass index (BMI) >23 kg/m(2), polyhydramnios (a trend), pregnancy-induced hypertension (a trend), oligohydramnios (a trend) and a gap between pregnancies of <2 years had a higher risk. As regards previous pregnancies, women with poor obstetric outcomes - miscarriage and pre-term labour - had a trend to greater risk in comparison with those who had either had vaginal delivery or caesarean section. Conclusion. BM I >23 kg/m(2) and a spacing gap of <2 years between pregnancies were significant risk factors, whereas those having had a vaginal birth in previous pregnancies in this population had a diminished risk of developing GDM. A larger study is required to demonstrate significance in other factors.