Neither covid-19 infection nor vaccination during the first trimester of pregnancy is associated with increased risk of major birth defects, finds a study from Scandinavia published by The BMJ today. It's well known that women who experience covid-19 infection during pregnancy are at increased risk of severe illness and have a higher risk of complications, including preterm birth and stillbirth. Less clear is the risk of birth defects (congenital anomalies) after infection with or vaccination against covid-19 as it has only recently become possible to study this research question.
To explore this, researchers used national health registries to identify 343,066 liveborn single infants in Sweden, Denmark and Norway with an estimated start of pregnancy between 1 March 2020 and 14 February 2022 and a minimum of nine months of postnatal follow-up time. Information on laboratory-confirmed polymerase chain reaction (PCR) positive covid-19 tests and vaccination was obtained from national health records and vaccination registries. Major congenital anomalies were grouped according to EUROCAT definitions and included defects of the heart, nervous and respiratory systems, eye, ear, face and neck anomalies, oro-facial clefts, genital and limb anomalies.
Potentially influential factors such as mother's age, education, country of birth, weight (BMI), existing chronic conditions, and smoking during pregnancy, were also accounted for in the analyses. Of the 343,066 infants included in the inf.