Comparison of the pregnancy outcomes and the incidence of fetal congenital abnormalities in infertile women treated with letrozole and clomiphene citrate

Objectives: The aim of the study was to evaluate the incidence of congenital fetal anomalies reported among infertile Iranian women treated with letrozole compared to those treated with Clomiphene Citrate (CC). Methods: This retrospective case-control study was performed based on information available from infertile patients referred to the Akbar-Abadi Hospital IVF Center, Tehran, Iran, undergoing ovulation induction (OI) or intrauterine insemination (IUI) cycles from 2007 to 2014.We compared sonographic findings, fertility results, pregnancy complications and congenital anomalies in two groups of women treated with letrozole and CC. Results: Overall, the results of the 2009 cycles including 1237 CC cycles and 772 letrozole cycles were evaluated. In spite of a higher chance of ovulation following CC treatment, overall fertility rates were similar in the two treatment groups. The frequency of adverse outcomes of pregnancy was similar in the two groups, except for the incidence of first trimester abortion, which was significantly higher in the CC-treated group. The frequency of fetal anomalies and major chromosomal abnormalities in the Letrozole group was 4.76% (five cases), and in the CC group, it was 2.12% (three cases). This difference was not statistically significant. Conclusion: Based on the findings of this study, it seems that the incidence of congenital anomalies in offspring after OI with letrozole is not increased compared to the CC group.