Higher Pregnancy Success Rates in Patients with Diminished Ovarian Reserve < 40 Years When Initially Treated by...

For women with idiopathic diminished ovarian reserve (DOR), direct start with IVF has been suggested to potentially shorten the time to pregnancy. Others however prefer intra-uterine insemination with ovarian stimulation (IUI + OS) due to the expected low response in IVF. In this pilot study, we determined the effect of these two strategies in women with DOR < 40 years. From a retrospective cohort, we included 135 women that met the diagnostic criteria of DOR. Patients were randomly referred to two different outpatient clinics in the Netherlands between 2012-2018 because of subfertility. Primary outcome was clinical pregnancy; secondary outcomes included ongoing pregnancies, live births, time to pregnancy and pregnancy-related complications. An instrumental variable analysis was used to assess the average effect of treatment with IUI + OS followed by IVF (protocol A) compared to IVF alone (protocol B) and correct for (unknown) confounders. Treatment protocol A was performed in 72.6% patients in Centre 1 and 30.6% in Centre 2. In Centre 1 61.6% (45/73) women had a clinical pregnancy compared to 41.9% (26/62) in Centre 2 (difference 19.7% (95% CI 3.1%-36.3%), p = 0.02). Early miscarriage occurred in 24% of the women in Centre 1 in comparison to 45% of the women in Centre 2. There were no significant differences in pregnancy-related complications. This pilot study suggests that women < 40 with DOR, if treated with IUI + OS followed by IVF, have higher estimated cumulative clinical pregnancy success, with a trend towards higher ongoing pregnancies and live births, in comparison to women treated with IVF alone.