Assessment of clinical pregnancies in up to eight ovarian stimulation with intrauterine insemination treatment cycles in those unable to proceed with in vitro fertilization

Abstract

Objective: To study the primary objective of clinical pregnancy (CP) rate per ovarian stimulation with intrauterine insemination (OS-IUI) treatment cycle in patients with repetitive cycles up to a maximum of 8 cycles.

Design: Retrospective cohort.

Setting: Large fertility clinic.

Patients: A total of 37,565 consecutive OS-IUI cycles from 18,509 patients were included in this study.

Interventions: Those with anovulatory diagnoses, tubal factor infertility, male factor infertility, using donor sperm, canceled cycles, and those with missing data for either baseline characteristics or outcome were excluded. The CP rate was analyzed using generalized estimating equations and controlled for age, stimulation protocol, and body mass index.

Main outcomes measures: Clinical pregnancy was defined as intrauterine gestation with fetal heartbeat visible on ultrasound.

Results: A total of 37,565 consecutive OS-IUI cycles from 2002 through 2019 at a private practice facility were evaluated. All cycles met inclusion criteria and were used in generalized estimating equation modeling. Patients aged <35 years comprised 47.6% of the cohort. After adjustment for confounders, the mean predicted probability of CP for cycles one to 8 was 15.7% per cycle. The mean predicted probability of CP in aggregated data from cycles 2 to 4 was only 1.7% lower compared with cycle 1 as the referent (16.7% vs. 15.0%, 95% confidence interval [CI] 2nd: 0.88 {0.82, 0.95}, 3rd: 0.86 {0.79, 0.93}, 4th: 0.88 {0.79, 0.98}). However, the 15.0% mean predicted probability of CP for the second through the fourth cycle was concordant with the mean for all included cycles (15.7%). The mean predicted probability of CP of cycles 5 to 8 was not significantly different compared with the referent (16.7% vs. 16.1%, 95% CI 5th: 0.97 [0.85, 1.11], 6th: 0.93 [0.79, 1.10], 7th: 1.01 [0.81, 1.26], 8th: 1.01 [0.76, 1.34]). The modeling of consecutive cycles suggested that the adjusted cumulative predicted probability of CP from OS-IUI continues to increase with each of the 8 successive cycles.

Conclusion: Clinical pregnancy rates are satisfactory in up to 8 consecutive OS-IUI treatment cycles. These data are useful for counseling, especially in those patients for whom in vitro fertilization is not financially or ethically feasible.

Keywords: Ovarian stimulation; clinical pregnancy; intrauterine insemination.