Comparison of congenital malformations among babies born after administration of letrozole or clomiphene citrate for infertility treatment in a Korean cohort.

This retrospective study investigated and compared the incidence of congenital foetal anomalies after letrozole versus clomiphene citrate (CC) administration for infertility treatment. Data from 142 newborns were included: letrozole group, n = 83; CC group, n = 61. Congenital anomalies were found in 7.2% (6/83) patients in the letrozole group and 18.0% (11/61) patients in the CC group, with no significant between-group difference (p = .066). Major congenital anomaly rate was 2.4% (2/83) in the letrozole group and 3.3% (2/61) in the CC group, with no significant between-group difference (p > 0.999). There was no significant difference in major and minor congenital anomalies between the groups after excluding premature infants (birth at a gestational age of <37 weeks), low birth weight, and very low birth weight. The results of this study demonstrate the stability of letrozole compared to that of CC for infertility treatment in pregnant women.