Couples with unexplained subfertility and unfavorable prognosis: a randomized pilot trial comparing the effectiveness of in vitro fertilization with elective single embryo transfer versus intrauterine insemination with controlled ovarian stimulation.

Objective: To evaluate the effectiveness of IVF with elective single embryo transfer (IVF-eSET) vs. IUI with controlled ovarian stimulation (IUI-COS) as an alternative treatment to reduce the risk for a multiple pregnancy.

Design: Randomized pilot trial.

Setting: Three academic and six teaching hospitals in the Netherlands.

Patient(s): Couples with unexplained or mild male subfertility and an unfavorable prognosis for natural conception.

Intervention(s): One cycle of IVF-eSET or three cycles of IUI-COS.

Main Outcome Measure(s): Ongoing pregnancy per couple.

Result(s): We randomly allocated 116 women to IVF-eSET (n = 58) or IUI-COH (n = 58). There were 14 ongoing pregnancies (24%) in the IVF-eSET group and 12 pregnancies (21%) in the IUI-COS group (relative ratio 1.17; 95% confidence interval 0.60-2.30). There were two twin pregnancies in the IVF-eSET group (14%) and two twin pregnancies and one triplet pregnancy in the IUI-COH group (25%).

Conclusion(s): In patients with unexplained or mild male subfertility and a poor prognosis for natural conception, one cycle of IVF-eSET might be as effective as three cycles of IUI-COS as primary treatment. Elective single embryo transfer does not seem an effective strategy in preventing multiple pregnancies in this particular population. In the future a strict SET policy (i.e., compulsory SET) might be an option. Our trial provides evidence for the feasibility and highlights the importance of a large definitive trial to determine the effectiveness and side effects of both strategies.