The impact of ovarian stimulation on the outcome of intrauterine insemination treatment: an analysis of 8893 cycles.
To evaluate the impact of ovarian stimulation on the outcome of intrauterine insemination (IUI). Retrospective analysis. A single university-based centre. A total of 5109 couples with 8893 cycles. The outcome of IUI with different protocols for ovarian stimulation was examined. The live birth rate (LBR), twin pregnancy rate and ovarian hyperstimulation syndrome (OHSS). 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. 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. In ovulatory women, ovarian stimulation with letrozole and HMG resulted in a significantly improved LBR.