Background Concerns have been raised regarding a potential surge of COVID-19 in pregnancy, secondary to rising numbers of COVID-19 in the community, easing of societal restrictions, and vaccine hesitancy. Even though COVID-19 vaccination is now offered to all pregnant women in the UK, there are limited data on its uptake and safety. Objectives and study design : This was a cohort study of pregnant women who gave birth at St George’s University Hospitals NHS Foundation Trust, London, UK, between March 1 st and July 4 th 2021. The primary outcome was uptake of COVID-19 vaccination and its determinants. The secondary outcomes were perinatal safety outcomes. Data were collected on COVID-19 vaccination uptake, vaccination type, gestational age at vaccination, as well as maternal characteristics including age, parity, ethnicity, index of multiple deprivation score and co-morbidities. Further data were collected on perinatal outcomes including stillbirth (fetal death ≥24 weeks’ gestation), preterm birth, fetal/congenital abnormalities and intrapartum complications. Pregnant women who received the vaccine were compared with a matched cohort of propensity balanced pregnant women to compare outcomes. Effect magnitudes of vaccination on perinatal outcomes were reported as mean differences or odds ratios with 95% confidence intervals. Factors associated with antenatal vaccination were assessed with logistic regression analysis. Results Data were available for 1328 pregnant women of whom 141 received at least one dose of vaccine before giving birth and 1187 women who did not; 85.8% of those vaccinated received their vaccine in the third trimester and 14.2% in the second trimester. Of those vaccinated, 128 (90.8%) received an mRNA vaccine and 13 (9.2%) a viral vector vaccine. There was evidence of reduced vaccine uptake in younger women (P=0.002), those with high levels of deprivation (i.e., fifth quintile of Index of Multiple Deprivation, P=0.008) and women of Afro-Caribbean or Asian ethnicity, compared to Caucasian ethnicity (P<0.001). Women with pre-pregnancy diabetes had increased vaccine uptake (P=0.008). In the multivariable model adjusting for variables that had a significant effect according to the univariable analysis, fifth deprivation quintile (most deprived) was significantly associated with lower antenatal vaccine uptake (adjusted OR 0.09, 95% CI 0.02–0.39, P=0.002), while pre-pregnancy diabetes was significantly associated with higher antenatal vaccine uptake (adjusted OR 11.1, 95% CI 2.01–81.6, P=0.008). In a propensity score matched cohort, compared with non-vaccinated pregnant women, 133 women who received at least one dose of the COVID-19 vaccine in pregnancy (vs. those unvaccinated) had similar rates of adverse pregnancy outcomes (P>0.05 for all): stillbirth (0.0% vs 0.3%), fetal abnormalities (2.2% vs 2.7%), intrapartum pyrexia (3.7% vs 1.5%), postpartum hemorrhage (9.8% vs 9.5%), cesarean section (30.8% vs. 30.6%), small for gestational age (12.0% vs 15.8%), maternal high dependency unit or intensive care admission (6.0% vs 3.5%) or neonatal intensive care unit admission (5.3% vs 5.4%). Mixed-effects Cox regression showed that vaccination was not significantly associated with birth <40 weeks’ gestation (hazard ratio 0.93, 95% CI 0.71–1.23, P=0.630). Conclusions Of pregnant women eligible for COVID-19 vaccination, less than one third accepted COVID-19 vaccination during pregnancy and they experienced similar pregnancy outcomes. There was lower uptake among younger women, non-white ethnicity, and lower socioeconomic background. This study contributes to the body of evidence that having COVID-19 vaccination in pregnancy does not alter perinatal outcomes. Clear communication to improve awareness among pregnant women and healthcare professionals on vaccine safety is needed, alongside strategies to address vaccine hesitancy. This includes post-vaccination surveillance to gather further data on pregnancy outcomes, particularly after first trimester vaccination, as well as long-term infant follow-up.
