Does ovarian stimulation benefit ovulatory women undergoing therapeutic donor insemination?

To compare clinical and ongoing pregnancy after natural cycle (NC) intrauterine insemination (IUI) versus ovarian stimulation (OS) IUI in ovulatory women undergoing therapeutic donor insemination (TDI).

Retrospective cohort.

Single infertility center.

A total of 76,643 IUI cycles in patients treated with intrauterine insemination were examined. Women undergoing TDI in the absence of diagnosed female factor infertility were included.

NC TDI or OS TDI with either clomiphene citrate or letrozole.

Clinical and ongoing pregnancies were analyzed by generalized estimating equations adjusting for age, body mass index, total motile sperm at time of insemination and cycle number. Ongoing multiple gestations were examined as a secondary outcome.

Six thousand one hundred ninety-two TDI cycles from 2,343 patients (711 patients without repeated IUI cycles) met inclusion criteria and were available for analysis (3,837 NC and 2,355 OS). There was no difference in mean age between the two groups (NC, 34.2 years vs. OS, 34.3 years). Probability of clinical and ongoing pregnancy was higher in the OS cohort compared with the NC cohort (OS, 22.4% vs. NC, 18.7% and OS, 15.4% vs. NC, 14.9%, respectively). However, OS significantly increased ongoing multiple gestations (OS, 10.8% vs. NC, 2.4%).

Ovarian stimulation in TDI cycles resulted in a <4% increase in clinical and <1% increase in ongoing pregnancy, and more than fourfold increase in ongoing multiple gestations. Natural cycle IUI should be considered as a first-line treatment for ovulatory women who need donor insemination.