THU321 Indirect Effects Of COVID-19 On The Risk Of Gestational Diabetes And Factors Mediating Increased Risk

Disclosure: Y.J. Rhou: None. J. Elhindi: None. S.J. Melov: None. N. Cheung: None. D. Pasupathy: None. Aim: COVID-19 has had indirect effects on pregnancy outcomes. This study aimed to assess the risk of gestational diabetes (GDM) in distinct COVID-19 exposure periods and determine the potential factors contributing to increased risk of GDM in a multiethnic population. Methods: Multicentre, retrospective cohort study of singleton pregnancies at three hospitals two years pre-COVID-19 (January 2018 - January 2020), 1(st) year of COVID-19 with low COVID-19 pandemic burden and limited restrictions (February 2020 - January 2021), and 2(nd) year of COVID-19 with increased pandemic burden and stringent restrictions (February 2021 - January 2022). Baseline maternal characteristics, gestational weight gain (GWG) and pregnancy outcome data were compared between time periods. The primary outcome of GDM was assessed using univariate and multivariate generalized estimating equations models. Results: Of 28,207 pregnancies, 14,663 occurred in the two years pre-COVID-19, 6,890 in COVID-19 Year 1 and 6,654 in COVID-19 Year 2. The study population was diverse, comprising 82.5% of non-Caucasian ethnicity and 22.7% in the quintile of greatest socioeconomic disadvantage. Maternal age increased across exposure periods (30.7 ± 5.0 years pre-COVID-19 vs 31.0 ± 5.0 years COVID-19 Year 1 vs 31.3 ± 5 years COVID-19 Year 2; p<0.001). There were increases in prepregnancy BMI (25.5 ± 5.7 kg/m(2) vs 25.7 ± 5.6 kg/m(2) vs 26.1 ± 5.7 kg/m(2); p<0.001), proportion who were obese (17.5% vs 18.1% vs 20.7%; p<0.001) and proportion with other traditional risk factors for GDM including South Asian ethnicity and prior history of GDM. Weekly rate of GWG and proportion exceeding recommended GWG increased across pandemic exposure periods (64.3% vs 66.0% vs 66.6%; p=0.009). GDM diagnosis increased across exposure periods (21.2% vs 22.9% vs 24.8%; p<0.001). Both COVID-19 Year 1 and Year 2 were associated with increased risk of GDM on univariate analysis, only COVID-19 Year 2 remaining significantly associated after adjusting for maternal baseline characteristics and GWG (OR 1.17 [1.06, 1.28], p=0.01). Conclusion: Diagnosis of GDM increased with pandemic exposure. Progressive sociodemographic changes and greater GWG may have contributed to increased risk. However, exposure to the 2(nd) year of COVID-19 remained independently associated with GDM after adjusting for shifts in baseline maternal characteristics and GWG. Presentation: Thursday, June 15, 2023