The COVID-19 pandemic and prevalence of gestational diabetes: Does gestational weight gain matter?

Abstract

Previous European reports indicated increased gestational diabetes (GDM) prevalence among relatively lean cohorts during the COVID-19 pandemic [1,2]. Less is known about how the pandemic impacted GDM prevalence in the United States; specifically, among those with morbid obesity. Pregnant people with obesity have been reported to be at increased risk of excessive gestational weight gain (GWG) during the COVD-19 pandemic [3] which may have further increased the risk of GDM among this group. The primary aim was to investigate whether the prevalence of GDM increased among our delivering patients, with consideration of their weight status, during the COVID-19 pandemic. The secondary aim was to determine if GDM diagnosis was associated with increased GWG. This retrospective cohort study included patients with a singleton, term birth who delivered pre-COVID-19 (January 2019-May 2020) and during the COVID-19 pandemic (July 2020-November 2021) at a single academic institution. As recommended by the American College of Obstetricians and Gynecologists, prenatal patients at our institution are screened for GDM between 24-28 weeks gestation [4]. Patients that were screened before March 2020 (the declared start of the COVID-19 pandemic) would have been delivered, at term, by the end of May 2020. Therefore, the pre-COVID-19 time period was defined as Jan 2019-May 2020 to capture term deliveries where GDM screening occurred before March 2020. We included a one month "wash out" period (June 2020) to ensure only those diagnosed with GDM during the COVID-19 time period were captured (July 2020 - Nov 2021). This study was approved by the UTGSM IRB#4907. Patients with pre-existing type 1 or 2 diabetes mellitus, a multi-gestation pregnancy, pre-term delivery, or unknown gestational age at delivery were excluded. Data collected on delivery admission included height, pre-pregnancy weight, weight at delivery, maternal age, race/ethnicity, and diagnosis of GDM. Pre-pregnancy Body Mass Index (BMI, kg/m2) was calculated using height and pre-pregnancy weight. To examine potential differences in patients with higher classes of obesity, standard weight status categories based off BMI were created. These include Underweight BMI <18.5, Healthy BMI 18.5-<25, Overweight BMI 25.0-<30, Obese Class 1 BMI 30.0-<35, Obese Class 2 BMI 35.0-<40, and Obese Class 3 BMI 40 or higher. GWG was calculated by pre-pregnancy weight deducted from weight at delivery. This study followed STROBE reporting guidelines. Binary and multiple regression analyses were used to identify potential difference in GDM diagnosis pre-COVID-19 pandemic vs. during COVID-19, controlling for potentially confounding factors (including weight status, maternal and gestational age, GWG, and race/ethnicity). Student's t-tests were used to assess the impact of the COVID-19 pandemic on GWG, stratified by weight status, among those with GDM. A p-value of 0.05 was considered statistically significant. Data were analyzed in SPSS Version 28 (IBM). During COVID-19, 12.2% of patients were diagnosed with GDM, compared to 9.9% pre-COVID-19 (p<0.001). Those with GDM diagnosis had an associated lower GWG relative to those without GDM, in the unadjusted and adjusted model (p<0.001) (Table 1). Among those diagnosed with GDM, there was no significant difference in GWG in the pre-COVID or during COVID groups, or when stratified by any weight status categories (data not shown) (p>0.05). The prevalence of GDM increased by 22.2% among delivering patients during the COVID-19 pandemic. However, no significant increase in GWG, even among those with obesity, was noted. Like other cohorts[2], GWG was significantly lower among those with GDM, potentially reflecting standard clinical care regimens of dietary therapy for this population. A potential mechanism for this increased GDM trend, despite no significant changes in GWG, remains unexplored, but maternal stress is a proposed contributor to gestational hyperglycemia[2]. Future research is needed to determine whether this increase was correlative or if causal events related to the pandemic lead to increased gestational hyperglycemia, and whether GDM diagnosis will return to pre-COVID-19 values.