Two is not always greater than one: patients with one ovary have similar assisted reproductive technology (ART) outcomes compared to patients with two ovaries

PURPOSE: To assess assisted reproductive technology (ART) outcomes in patients with one ovary compared to two ovaries. METHODS: We performed a retrospective cohort study of all patients with one ovary who underwent ≥ 1 ART cycle between 2012 and 2020 at a large university-affiliated fertility center. Patients were 3-to-1 matched with two ovary controls during the same period. Primary outcome was metaphase II oocytes (MIIs) retrieved per cycle. Secondary outcomes included ovarian reserve markers, laboratory outcomes, and live birth rates (LBRs). RESULTS: A total of 104 one ovary patients (158 cycles; median age 35.5 years) were matched to 312 two ovary patients (474 cycles; median age 35.0 years). In one ovary patients, anti-Mullerian hormone was lower (median 1.1 vs. 2.2, p < 0.01) and day 2 follicle-stimulating hormone was higher (median 7.4 vs. 6.2, p < 0.01). One ovary patients yielded median 7.5 MIIs and 10 oocytes per cycle, fewer than two ovary patients (11.0 and 14.5, respectively; p  5.8, p  0.40). Among the one and two ovary groups, LBRs per transfer (45.8% vs. 46.6%, p = 1.00) and per patient who underwent transfer (68.3% vs. 73.9%, p = 0.55) were equivalent. CONCLUSION: One ovary patients yielded fewer MIIs and oocytes than two ovary patients, but had ≥ 50% the yield of two ovary patients, suggesting a compensatory mechanism in oocyte yield in the solitary ovary. One and two ovary patients had equivalent LBRs.