What is the “cost” of reducing adverse pregnancy outcomes in patients with gestational diabetes mellitus - risk factors for perinatal complications in a retrospective cohort of pregnant women with GDM

BACKGROUND: Gestational diabetes mellitus (GDM) is a frequent pregnancy complication, affecting the maternal and neonatal health. The new diagnostic strategy for GDM, proposed by the International Association of Diabetes and Pregnancy Study Groups in 2010 and World Health Organization in 2013, raised hope to reduce perinatal complications. The purpose of the study was to compare risk factors influencing maternal and foetal outcomes in a group of pregnant women diagnosed with GDM, and in a group of pregnant women without GDM, regardless of the adopted diagnostic criteria. Also, the aim of the study was to evaluate the impact of risk factors on perinatal results and the “cost” of reducing adverse pregnancy outcomes in patients with GDM. METHODS: It was a retrospective study based on the analysis of births given after 37 weeks of pregnancy at the 2nd Department of Obstetrics and Gynaecology, Warsaw Medical University during the years 2013 to 2015. All pregnant women had a 75 g OGTT between the 24th and 28th weeks of pregnancy. The study compared risk factors for perinatal complications in 285 GDM patients and in 202 randomly selected women without GDM. The impact of selected risk factors on perinatal outcomes was analysed. RESULTS: Both the diagnosis of GDM and maternal BMI prior to pregnancy, significantly modified the risk of excessive and insufficient weight gain during pregnancy. The parameters significantly influencing the risk of the composite adverse maternal outcome were the maternal abdominal circumference [OR: 1.08 (1.04; 1.11)] and multiparity, which reduced the risk by almost half [OR: 0.47 (0.30; 0.75)]. The maternal abdominal circumference before the delivery was a strong factor correlating with the occurrence of perinatal complications in both the mother and the foetus in the entire cohort. A circumference over 100 cm increased the risk of at least one maternal complication (increased blood loss, soft tissue injury, pre-eclampsia) by almost 40% (OR 1.38, p < 0.001). CONCLUSIONS: No differences were found in maternal and foetal outcomes in GDM and non-GDM women except gestational weight gain below Institute of Medicine recommendations. The only “cost” of reducing adverse pregnancy outcomes in GDM patients seems to be lowering gestational weight gain, the future impact of which on GDM pregnant population should be assessed. The maternal abdominal circumference measured before delivery not the severity of carbohydrate intolerance, remained the main predictor for significant perinatal complications.