Anaesthetic exposure during early pregnancy may exert foetal cardiac teratogenic effects

Exposure to general anaesthesia during critical periods of foetal heart development appears to contribute to a heightened risk of congenital heart defects, a study reports.

The study drew data from a longitudinal cohort study of 2,095,300 pregnancies resulting in live births in hospitals of Quebec, Canada. Inclusion criteria was receipt of general or local/regional anaesthesia in the first trimester, such as between 3 and 8 weeks after conception, which is considered the critical weeks of foetal cardiogenesis.

The main outcome measures were critical and noncritical heart defects in offspring. Overall, congenital heart defects had an incidence rate of 107.3 per 10,000 infants exposed to anaesthesia as opposed to 87.2 per 10,000 unexposed infant controls.

Log-binomial regression models adjusted for maternal characteristics showed that compared with no anaesthesia, anaesthesia exposure between 3 and 8 weeks following conception was associated with a 1.5-fold higher risk of congenital heart defects in the offspring (95 percent confidence interval [CI] 1.11–2.03).

Receipt of anaesthesia between 5 and 6 weeks after conception conferred an almost 1.8-fold risk increase (95 percent CI, 1.10–3.08).

Associations were driven mostly by general anaesthesia, which contributed to 2.49 times greater risk of congenital heart defects in the offspring between weeks 5 and 6 postconception (95 percent CI, 1.40–4.44).

More studies are needed to confirm whether anaesthetic agents are cardiac teratogens.