A "four-cycle program" improves the estimate of the cumulative pregnancy rate and increases the number of actual pregnancies in IUI treatment: a cohort study

Objective: To demonstrate that reduction of the cumulative dropout rate (CDR) improves the accuracy of the estimate of the cumulative pregnancy rate (CPR) in a set of four intrauterine insemination (IUI) cycles ("four-cycle program") and increases the total number of pregnancies obtained.

Study design: Single-centre retrospective observational cohort study of couples who underwent IUI cycles at the Andros Day Surgery Clinic, Palermo, from 1997 to 2011. The main outcome measure was the calculation of the CPR, with life table analysis, firstly by giving the same probability of pregnancy to the dropouts as the patients who continued the treatment (usual method) and secondly by considering this probability null (conservative method). The difference between these two methods was used to verify the accuracy of the estimate.

Result(s): In the 15 years, 924 couples underwent 2956 cycles carried out consecutively in a set of four cycles. The CDR was 16%. The CPR was 31.4% with the usual method and 29.1% with the conservative method. The difference between the two estimates was not significant, indicating a high reliability of the results and a good accuracy of the calculation. Furthermore, maintenance of a low CDR permits improvement of the CPR, as was demonstrated by considering scenarios with worse dropout rates.

Conclusion(s): The "four-cycle program" results in a reduction in the CDR, allowing a better estimation of the CPR, and increases the number of actual pregnancies in IUI. The CPR should become the focus for reporting outcome rates in IUI cycles. Reduction of the dropout rate allows us to give the patient a more reliable and accurate estimate of the pregnancy rate.