Association of Maternal Inactivated COVID-19 Vaccination within 3 Months before Conception with Neonatal Outcomes

Abstract

There is limited available data addressing whether inactivated COVID-19 vaccination before conception is associated with adverse neonatal outcomes. This cohort study included all singleton live births at our center from March 1 to June 30, 2022. According to whether a maternal inactivated COVID-19 vaccination had been administered within 3 months before conception or not, neonates were identified as being in the vaccinated or unvaccinated group. Vaccination information and clinical characteristics were extracted for analysis. Furthermore, neonatal outcomes were analyzed and compared between these two groups in the present study. The cohort included 856 eligible newborns, of whom 369 were exposed to maternal vaccination before conception and 487 were unexposed newborns. No differences were observed in rates of preterm birth, newborns being small for gestational age, or neonatal intensive care unit admission between exposed and unexposed newborns. Furthermore, even after adjusting for social-economic status and maternal characteristics, there remained no significant differences in these neonatal outcomes. Our study revealed no statistically significant differences between newborns born to women who received inactivated vaccines prior to conception compared with those who did not receive any vaccinations. In addition, our study also highlights the importance of considering COVID-19 vaccination before conception.

Keywords: COVID-19; NICU admission; preterm birth; small for gestational age; vaccination.

Figure 1

Flowchart of Newborn Selection for Cohort Study of maternal inactivated COVID-19 vaccination within 3 months before conception. A total of 2606 infants were born in our center from March to June 2022; 1750 were excluded, and a total of 856 neonates remained eligible for analysis, of whom 369 were exposed to maternal vaccination before conception.

Figure 2

Primary neonatal outcomes adjusted by different models. Primary neonatal outcomes including preterm, SGA, and NICU admissions have been adjusted by different models and shown in forest plots. (Model 1: crude model; Model 2: adjusted for social–economic status, including per capita annual disposable income levels and education levels; Model 3: further adjusted for maternal age at delivery, obesity during pregnancy, whether the conception was planned or not and whether it was achieved through assisted reproductive technology, history of abnormal pregnancy, and whether there was a preterm infant.). Abbreviations: SGA, small for gestational age. OR: odds ratio; CI, confidence interval.

Figure 3

Probability of neonatal outcomes according to the time interval between the first dose of vaccination and the last menstrual period (LMP), as a continuous variable. The horizontal axis represents the time interval between the 1st dose of the COVID-19 vaccine and the LMP in days, as a continuous variable, and the vertical axis represents the probability of a given neonatal outcome. The spline smoothing plot and the shaded areas represent the probability of the neonatal outcome and its 95% CI. Covariates in the adjusted model included: per capita annual disposable income (<4380 USD per year vs. ≥4380 USD per year) and education level (junior high or below, senior high, college or above), maternal age at delivery, obesity during pregnancy, whether the conception was planned or not and whether it was achieved through assisted reproductive technology, history of abnormal pregnancy, and whether there was a previous preterm infant.