The impact of prenatal maternal mental health during the COVID-19 pandemic on birth outcomes: two nested case-control studies within the CONCEPTION cohort

Objective Assess the association between prenatal mental health during the COVID-19 pandemic and preterm birth (PTB; delivery < 37 weeks gestation) and low birth weight (LBW; < 2500 g).Methods Pregnant individuals, > 18 years, were recruited in Canada and provided data through a web-based questionnaire. We analyzed data on persons recruited between 06/2020 and 08/2021 who completed questionnaires while pregnant and 2 months post-partum. Data on maternal sociodemographics, comorbidities, medication use, mental health (Edinburgh Postnatal Depression Scale, General Anxiety Disorder-7, stress), pandemic hardship (CONCEPTION-Assessment of Stress from COVID-19), and on gestational age at delivery and birth weight were self-reported. Crude and adjusted odds ratios (aOR) with 95% confidence interval (95%CI) were calculated to quantify the association between PTB/LBW and maternal mental health.Results A total of 1265 and 1233 participants were included in the analyses of PTB and LBW, respectively. No associations were observed between PTB and prenatal mental health (depression [aOR 1.01, 95%CI 0.91-1.11], anxiety [aOR 1.04, 95%CI 0.93-1.17], stress [aOR 0.88, 95%CI 0.71-1.10], or hardship [aOR 1.00, 95%CI 0.96-1.04]) after adjusting for potential confounders. The risk of PTB was increased with non-white ethnicity/race (aOR 3.85, 95%CI 1.35-11.00), consistent with the literature. Similar findings were observed for LBW (depression [aOR 1.03, 95%CI 0.96-1.13], anxiety [aOR 1.05, 95%CI 0.95-1.17], COVID stress [aOR 0.92, 95%CI 0.77-1.09], or overall hardship [aOR 0.97, 95%CI 0.94-1.01]).Conclusion No association was found between prenatal mental health nor hardship during the COVID-19 pandemic and the risk of PTB or LBW. However, it is imperative to continue the follow-up of mothers and their offspring to detect long-term health problems early.