The ovarian sensitivity index is predictive of live birth chances after IVF in infertile patients

Study question: Does the ovarian sensitivity index (OSI) predict embryo quality, pregnancy and live birth in patients undergoing FSH/hMG stimulation for IVF?

Summary answer: The OSI is predictive of pregnancy and live birth in older women with a more unfavorable prognosis undergoing FSH/hMG stimulation for IVF.

What is known already: The OSI was previously reported to reflect gonadotrophin requirements among high, normal and poor responders and to predict pregnancy potential in younger patients undergoing ovarian stimulation with FSH.

Study design size duration: A retrospective cohort study that included 1282 women undergoing IVF with FSH/hMG stimulation was carried out between January 2010 and December 2016.

Participants/materials setting methods: We evaluated 1282 women who underwent fertility treatment with FSH/hMG stimulation and oocyte retrieval at an academically affiliated private fertility center. OSI was calculated as (oocytes ×1000)/total gonadotrophin dose and grouped into two classes based on a receiver operating characteristic (ROC) curve analysis of a randomly selected development sample comprising one-third of the cycles. The remaining cycles comprised the validation group. ROC curves were also used to compare the predictive value of OSI to that of baseline FSH and anti-Müllerian hormone (AMH). Logistic regression models evaluated the effect of high (OSI >0.83) and low (OSI ≤0.83) on clinical pregnancy and live birth in the validation group. Models were adjusted for female age, baseline FSH, AMH and oocyte yield and gonadotrophin dose.

Main results and the role of chance: Women presented with a mean ±SD age of 38.6 ± 5.4 years and showed median AMH levels of 0.65 (95% CI 0.61-0.74) ng/ml. They received 5145 ± 2477 IU of gonadotrophins and produced a median 5.2 (95% CI 5.0-5.5) oocytes. Pregnancy and live birth rates per oocyte retrieval for all women were 20.6% and 15.8%, respectively. Patients with higher OSI (less gonadotrophin required per oocyte retrieved) produced significantly more high-quality embryos than patients with low OSI (3.5 (95% CI 3.2-3.8) versus 0.6 (95% CI 0.5-0.7) (P = 0.0001)) and demonstrated higher pregnancy (23.2% versus 9.7%) and live birth rates (8.8% versus 5.3%) than their counterparts (P = 0.0001 and P = 0.0001, respectively). After adjustments for age, baseline AMH and FSH, total gonadotrophin dosage and oocyte yield, an OSI >0.83 was associated with greater odds of pregnancy (odds ratio 2.12, 95% CI 1.30-3.45, P < 0.003) and live birth (odds ratio 1.91, 95% CI 1.07-3.41, P < 0.028).

Limitations reasons for caution: The results may not be applicable to women with excellent pregnancy potential or FSH-only stimulation.

Wider implications of the findings: The predictive capacity of OSI for embryo quality, pregnancy and live birth, which is independent of AMH or FSH, may help in counseling patients about their pregnancy potential and live birth chances.

Study funding/competing interests: Intramural funding from the Center for Human Reproduction and the Foundation for Reproductive Medicine. A.W., V.A.K., D.F.A., D.H.B. and N.G. have received research grant support, travel funds and speaker honoraria from various pharmaceutical and medical device companies: none, however, related to the topic presented here. D.H.B. and N.G. are listed as inventors on already awarded and still pending US patents, claiming beneficial effects on diminished ovarian reserve and embryo ploidy from dehydroepiandrosterone supplementation.

Trial registration number: N/A.