Abstract

STUDY QUESTION

Are intrauterine insemination (IUI) performance characteristics and post-processing total motile sperm count (TMC) related to live birth rate in couples with unexplained infertility?

SUMMARY ANSWER

Patient discomfort with IUI and lower inseminate TMC were associated with a reduced live birth rate, while time from hCG injection to IUI, sperm preparation method and ultrasound guidance for IUI were not associated with live birth success.

WHAT IS ALREADY KNOWN

We previously determined that some baseline characteristics of couples with unexplained infertility, including female age, duration of infertility, history of prior loss and income, were related to live birth rate across a course of ovarian stimulation and IUI treatment. However, the relationship between treatment outcomes and per-cycle characteristics, including ultrasound guidance for IUI, timing of IUI relative to hCG injection, difficult or painful IUI and inseminate TMC, are controversial, and most prior investigations have not evaluated live birth outcome.

STUDY DESIGN, SIZE, DURATION

This was a secondary analyses of 2462 cycles from the Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) clinical trial. This prospective, randomised, multicentre clinical trial determined live birth rates following IUI after ovarian stimulation with clomiphene citrate, letrozole or gonadotropins in 854 couples with unexplained infertility. It was conducted between 2011 and 2014, and couples could undergo up to four consecutive treatment cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

AMIGOS was an NIH-sponsored Reproductive Medicine Network trial conducted at 12 clinical sites. Participants were women with unexplained infertility who were between 18 and 40 years of age. Cluster-weighted generalised estimating equations (GEE), which account for informative clustering of multiple IUI treatment cycles within the same patient, were used to determine associations between IUI performance characteristics, including inseminate TMC, and live birth rate. Efficiency curves were also generated to examine the relationship between inseminate TMC and live birth rate.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjustment for treatment group and baseline factors previously associated with live birth across a course of OS-IUI treatment, patient discomfort during the IUI procedure was associated with a reduction in live birth rate (aRR 0.40 (0.16–0.96)). Time from hCG trigger injection to IUI was not significantly associated with outcome. Higher TMC was associated with greater live birth rate (TMC 15.1–20.0 million (14.8%) compared to ≤5 million (5.5%)) (aRR 2.09 (1.31–3.33)). However, live births did occur with TMC ≤ 1 million (5.1%).