Background: There is lack of clarity on whether pregnancies during COVID-19 resulted in poorer delivery and birth outcomes.

Aim: Compare delivery and birth outcomes in pregnant Ontario women before and during COVID-19 (pandemic periods).

Methods: Deliveries before (Jun 2018?Feb 2020) and during (Jul 2020?Mar 2022) COVID-19 were identified from health administrative data. We used logistic regressions to estimate odds ratios (OR) of delivery and birth outcomes and negative binomial regression for rate ratios (RR) of health services use (HSU). We compared those with prevalent chronic respiratory diseases (asthma, allergic rhinitis, or eczema) to those without these diseases. All regressions were adjusted for pandemic periods and other confounders.

Results: 323,359 deliveries were included (50% during pandemic). 1 in 5 (18.3%) women who delivered during the pandemic had not received any COVID-19 vaccine. While overall HSU rates were lower during the pandemic compared to before, pregnant women with respiratory conditions had higher all-cause hospitalization (RR=1.15, 95%CI: 1.10-1.19) and ED visit rates (RR=1.18, 95%CI: 1.16-1.20). They also had significantly higher odds of anxiety (OR=1.49, 95%CI: 1.45-1.54), preterm deliveries (OR=1.09, 95%CI: 1.05-1.12), but lower odds of C-section (OR=0.96, 95%CI: 0.95-0.98). These observed differences were not explained by vaccination status nor pandemic periods.

Conclusions: Women with prevalent respiratory conditions had higher odds of adverse delivery and birth outcomes and higher acute HSU rates. Ensuring ongoing prenatal care during the pandemic may reduce risks of adverse delivery outcomes and the need for acute care during pregnancy.