Gestational Diabetes during the Pandemic: Screening Methods and Outcomes in First-time GDM

ABSTRACT

Objective: To study the impact of national recommendations on the method of screening used for GDM during the COVID-19 pandemic, and evaluate differences in maternal and fetal outcomes among women with first-time GDM (ftGDM). Design: A retrospective observational study in a single Tertiary London Hospital. During the pandemic, the RCOG recommended an amended GDM screening protocol to reduce hospital attendance and risk of virus transmission (fasting blood glucose level ≥5.3 and/or HbA1c ≥39 at 28 weeks of gestation). Our Trust did not adopt this due to concerns regarding its sensitivity. We adopt a 2-step approach to universal GDM screening using a 50g glucose challenge test, and refer those screening positive for a full oral glucose tolerance test. Method: Outcomes were reviewed for women with ftGDM delivering a singleton at ≥24 weeks gestation between 01/04/20 -28/ 5/21. Our primary aim was to determine the impact of the change in COVID-19 GDM screening policy, had it been implemented. Our secondary outcomes included GDM management method, maternal and perinatal complications. We excluded women with a booking HbA1c ≥42 (indicative of pre-diabetes) and those who had bariatric surgery. Demographic and outcome data were obtained from electronic databases. Results: 247 women were diagnosed with ftGDM using local screening methods. Only 23 of these women had a HbA1c ≥39 at time of diagnosis and a further 12 had FBG ≥5.3. There was no significant difference in age or ethnicity between the two groups. The locally diagnosed group had a statistically significantly lower booking BMI (P<0.001) and were less likely to require pharmacological management of GDM (P<0.001). There were no significant differences in rates of induction of labour, gestation at delivery, birth weight or any perinatal adverse outcome. However, the women in the Covid-19 GDM screening group were significantly more likely to be delivered by Emergency Caesarean Section (p = 0.03) and have gestational hypertensive disease (p = 0.025). Conclusions: If we had implemented RCOG HbA1c screening, we would have not diagnosed 207 women with GDM, 41% of whom required pharmacological treatment. It is not surprising that women with higher HbA1c values had higher rates of maternal complications, due to the well-established association between maternal hyperglycaemia and adverse obstetric outcomes. As such, it is imperative that more sensitive screening protocols such as the 50g screen are considered in any future pandemics, such that women with GDM can be identified and maternal hyperglycaemia treated to benefit in-utero fetal programming.