Incidence of gestational diabetes mellitus before and after the Covid-19 lockdown: A retrospective cohort study

Aim: To evaluate whether the first Covid-19 lockdown for Italian citizens (March to July 2021) might have altered the incidence of gestational diabetes mellitus (GDM).

Methods: A retrospective single-center study in a tertiary referral center. Primary outcome was the incidence of GDM among pregnant women. GDM incidence, from June 11, 2019 to December 4, 2020, was compared by dividing the study time as follows: from the beginning of the study to before Covid-19 lockdown (from June 11, 2019, to March 9, 2020) and lockdown period (from March 10, 2020, to December 4, 2020). GDM was diagnosed with a 75-g, 2-h oral glucose tolerance test (OGTT) at 24-28 gestational weeks.

Results: Concerning 1295 women, GDM incidence increased during the lockdown period (9.3% vs. 3.4%, p < 0.001). Higher pregnancy weight gain with an increased body mass index (BMI) at the delivery was reported during the lockdown (31.3 vs. 28.4 kg/m² , p = 0.02 and mean weight gain of 9.3 vs. 6.6 kg, p = 0.007). There was no difference in other comorbidity incidence and OGTT values between the two groups.

Conclusions: Pregnant women during the Covid-19 lockdown might have experienced higher BMI and pregnancy weight gain with increased GDM diagnoses. This may be related to physical limitations and emotional distress experienced during the lockdown. However, evidence is limited due to restricted study duration and random variations of outcomes across time. More studies are needed to understand the dietary patterns and the physical activity changes during the Covid-19 lockdown and its impact on fetal outcomes.