Association of first trimester anaesthesia with risk of congenital heart defects in offspring

Abstract

Abstract Background A substantial number of pregnant women require anaesthesia for non-obstetric surgery, but the risk to fetal heart development is unknown. We assessed the relationship between first trimester anaesthesia and risk of congenital heart defects in offspring. Methods We conducted a longitudinal cohort study of 2 095 300 pregnancies resulting in live births in hospitals of Quebec, Canada, between 1990 and 2016. We identified women who received general or local/regional anaesthesia in the first trimester, including anaesthesia between 3 and 8 weeks post-conception, the critical weeks of fetal cardiogenesis. The main outcome measures were critical and non-critical heart defects in offspring. We estimated risk ratios (RR) and 95% confidence intervals (CI) for the association of first trimester anaesthesia with congenital heart defects, using log-binomial regression models adjusted for maternal characteristics. Results There were 107.3 congenital heart defects per 10 000 infants exposed to anaesthesia, compared with 87.2 per 10 000 unexposed infants. Anaesthesia between 3 and 8 weeks post-conception was associated with 1.50 times the risk of congenital heart defects (95% CI 1.11–2.03), compared with no anaesthesia. Anaesthesia between 5 and 6 weeks post-conception was associated with 1.84 times the risk (95% CI 1.10–3.08). Associations were driven mostly by general anaesthesia, which was associated with 2.49 times the risk between weeks 5 and 6 post-conception (95% CI 1.40–4.44). Conclusions General anaesthesia during critical periods of fetal heart development may increase the risk of congenital heart defects. Further research is needed to confirm that anaesthetic agents are cardiac teratogens.