Extending letrozole dosing in patients with polycystic ovary syndrome undergoing ovulation induction with intrauterine insemination.

OBJECTIVE

To determine the effect of prescribing a second course of letrozole within a single ovulation induction/intrauterine insemination (OI/IUI) cycle on pregnancy outcomes in patients with polycystic ovary syndrome (PCOS).

DESIGN

Retrospective cohort study.

SUBJECTS: Cases designated as OI/IUI in PCOS patients using letrozole alone for OI were identified. Patient (n = 183) and cycle (n = 405) demographics and outcomes were collected. Cycles in which an adequate response was achieved with a single course of letrozole (n = 333) were compared with cycles in which a second course was needed to achieve adequate follicular growth (n = 72). A second course was indicated in cases of suboptimal follicular growth after the initial course of letrozole. The relationships between single vs. a second course and pregnancy-related outcomes were examined adjusting for age and body mass index in logistic regressions.

EXPOSURE: Extended dosing with a second course of letrozole within an OI/IUI cycle in PCOS patients.

MAIN OUTCOME MEASURES: Clinical pregnancy.

RESULTS

The clinical pregnancy rate was not significantly different for the extended-dose cycles (15.3%,11/72) compared with single-dose cycles (13.5%, 45/333) (odds ratio [95% confidence limit] = 1.15 [0.56-2.36]). After adjusting for age and body mass index, there remained no significant difference between groups.

CONCLUSION

Extended dosing with a second course of letrozole in an OI/IUI cycle is associated with no significant difference in pregnancy and live birth outcomes. Thus, it is reasonable to give a second course of letrozole in a patient with PCOS, if indicated, which helps optimize the number of cycles needed to achieve pregnancy.