Background: In the past 20 years, various recommendations have been made about the maximum number of intrauterine insemination (IUI) cycles that should be performed, because evidence underpinning a possible limit is lacking.
Methods: We performed a multicentre, retrospective cohort analysis among couples treated with IUI up to nine cycles. Primary outcome measure was ongoing pregnancy rate (OPR) per cycle. Cumulative OPRs (COPR) after three, six and nine cycles of IUI were calculated using life-table analysis. Univariable and multivariable logistic regression analysis was performed to identify variables possibly affecting OPR's.
Results: Overall, 3714 couples with male, cervical or unexplained subfertility underwent 15,303 cycles of IUI. In 70% of cycles, controlled ovarian hyperstimulation (COH) was used (51% clomiphene-citrate, 19% gonadotropins). Mean OPR rate was 5.6% per cycle. OPR in the seventh, eighth and ninth cycle were 5.1%, 6.7% and 4.6%, respectively. Taking censored patients into account, the calculated COPR was 18% after the third cycle, 30% after the seventh cycle and 41% after the ninth cycle. If censored patients were considered to have no chance of conception, a crude COPR of 25% after nine cycles was found. Multivariable regression analysis showed no significant impact of age, type of subfertility, diagnosis, use of hyperstimulation or cycle number on OPR after the sixth treatment cycle.
Conclusions: OPR in high-order IUI cycles are acceptable, and do not offer a rationale for cancellation before nine cycles. Using this type of very mild COH, it may be reasonable to conduct up to nine cycles.