Does daily co administration of gonadotropins and letrozole during the ovarian stimulation improve IVF outcome for normal, poor and sub optimal responders?

Abstract

Background: Previous studies have described similar or improved IVF outcomes following co-administration of letrozole during ovarian stimulation (OS) in different patients' sub-populations.

Objectives: Address and identify the sub-group of patients that might benefit from letrozole co-treatment throughout the entire OS. Methods,Setting, Participants: We reviewed the medical files of patients attending our IVF unit over a three-year period, for different indications, who underwent two successive IVF cycle attempt, where the 2nd included the co-administration of 5 mg Letrozole from OS day 1 until trigger day.

Results: Two hundred patients met the inclusion criteria and were included in the study. Of whom, 65 were poor responders (oocytes≤ 3) during the first IVF cycle attempt, 85 were sub-optimal responders (4-9 oocytes) and 50 were normal responders (≥ 10 oocytes). The total dose of gonadotropins (4525±1553 vs. 4293±2166, p = NS) and length of stimulation (11.3±2.2 vs. 11.1±2.3, p=NS) were comparable between the two cycle attempts. Numbers of follicles ≥ 13mm (7.2±4.7 vs 6.2±4.3, p < 0.001), retrieved oocytes (8.6±6.1 vs. 6.9±5.5, p<0.001), zygotes (5.7±4.5 vs. 4.5±3.7 p<0.001) and number of TQE (2.5±2.5 vs. 1.8±1.9, p<0.001) were significantly higher in letrozole cycles. Sub analysis according to patients' ovarian response during the first attempt revealed that the poor and sub-optimal responders significantly benefit from the letrozole co-administration, while the normal responders did not.

Conclusions: Letrozole co-administration during OS for IVF increases the number of retrieved oocytes, zygotes and TQE in poor and suboptimal responders but not in normal responders.