The impact of ovarian stimulation on the outcome of intrauterine insemination treatment: an analysis of 8893 cycles

OBJECTIVE: To evaluate the impact of ovarian stimulation on the outcome of intrauterine insemination (IUI). DESIGN: Retrospective analysis. SETTING: A single university-based centre. POPULATION: A total of 5109 couples with 8893 cycles. METHODS: The outcome of IUI with different protocols for ovarian stimulation was examined. MAIN OUTCOME MEASURES: The live birth rate (LBR), twin pregnancy rate and ovarian hyperstimulation syndrome (OHSS). RESULTS: In ovulatory women without ovarian stimulation, the LBR was 7.6%. Stimulation with clomifene citrate (CC), letrozole (LE), human menopausal gonadotrophin (HMG), CC or LE combined with HMG achieved LBRs of 6.1, 5, 7.9, 8 and 12.2%, respectively. LE combined with HMG achieved a significantly improved LBR compared with no stimulation. HMG stimulation was associated with a higher rate of twins (7.4%) than no stimulation (0%, P < 0.01). In ovulatory women, the LBR appeared lower in CC and LE compared with no stimulation (P > 0.05). In anovulatory women, ovarian stimulation with CC, LE, HMG, CC or LE combined with HMG achieved LBRs of 11.3, 5.1, 11.8, 12.6 and 13.6%, respectively. No significant difference was observed. There were no triplet pregnancies or OHSS in stimulated cycles. CONCLUSIONS: In ovulatory women, ovarian stimulation with LE combined with HMG achieved a significantly improved live birth rate. HMG stimulation resulted in a high risk for twins. TWEETABLE ABSTRACT: In ovulatory women, ovarian stimulation with letrozole and HMG resulted in a significantly improved LBR.