Gestational Diabetes Mellitus- Testing in Third Trimester- New Data and Fresh Thinking

Abstract

BACKGROUNDGestational Diabetes Mellitus (GDM) is a common complication of pregnancy that is associated with adverse pregnancy outcomes. Studies have shown that GDM responds to early and effective intervention, which improves maternal and neonatal outcomes and reduces long-term risk of Type 2 Diabetes Mellitus (T2DM) in mother and child. The guidelines of the Diabetes in Pregnancy Group in India (DIPSI) currently recommend GDM testing twice during pregnancy, i.e. at the first antenatal visit and at 24 -28 weeks' gestation; however, GDM has been shown to develop in the third trimester. MATERIALS AND METHODSPregnant women receiving antenatal care at Divakars Speciality Hospital, Bengaluru, India, took part in the study. The participants were recruited on their first antenatal visit, and informed consent was obtained. GDM testing was carried out at 12 weeks and 22 -24 weeks' gestation, in keeping with the DIPSI guidelines. GDM testing was also carried out at 32 weeks' gestation based on clinical findings and scan reports. GDM prevalence rates at each time point were obtained, and Pearson chisquare tests were used to determine whether a GDM diagnosis was associated with age, parity and BMI. RESULTSThe mean age of the participants was 29.06 ± 4.28 yrs., and their average BMI was 25.67 ± 4.52 kg/m 2 . The prevalence of GDM during the first trimester, second trimester and third trimester were 8.60%, 11.1% (universal testing) and 8.1% (selective testing) respectively. For each of the study points, i.e. 12 weeks' gestation (T1), 22 -24 weeks' gestation (T2) and 32 weeks' gestation (T3), significant differences were not found between the ages (P (T1) = 0.247; P (T2) = 0.953; and P (T3) = 0.252), BMIs (P (T1) = 0.917; P(T2) = 0.098; and P (T3) = 0.670), and parities (P (T1) = 0.172; P (T2) = 0.321; and P (T3) = 0.321) of women who were diagnosed with GDM and those who tested negative for GDM. CONCLUSIONOur study shows that additional testing of pregnant women in the third trimester would identify cases of late onset GDM that would have otherwise gone undetected; making a case for considering universal testing once in every trimester.