RESUMO
CONTEXT: Resumption of ovarian activity and spontaneous pregnancies are described in patients with premature ovarian failure (POF), but there is a lack of data concerning the prevalence of and predictive factors for these phenomena. OBJECTIVE: The aim of the study was to determine both the prevalence of and predictive factors for spontaneous resumption of ovarian function in POF patients. DESIGN AND SETTING: A mixed retrospective and prospective study was performed at a referral center for reproductive endocrinology. PATIENTS: A total of 358 consecutive POF patients were followed from 1997 to 2010 in our center. MAIN OUTCOMES MEASURES: The cumulative incidence of resumption of ovarian function was determined, and predictive factors were identified by univariate and multivariate analysis. RESULTS: Of 358 patients with idiopathic POF, 86 (24%) patients presented features indicating resumption of ovarian function, and in 77 cases (88%) within 1 yr of diagnosis. Twenty-one spontaneous pregnancies (16 births, five miscarriages) occurred in 15 (4.4%) patients. Multivariate analysis (Cox model) showed that a familial history of POF, secondary amenorrhea, presence of follicles at ultrasound, and inhibin B and estradiol levels were significantly predictive of resumption of ovarian function (P < 0.01), whereas association with an autoimmune disease, anti-mullerian hormone level, the presence of follicles on biopsy, and/or genetic abnormalities did not appear predictive. We created a predictive score for resumption of ovarian function comprising age at diagnosis, presence of follicles at ultrasound, and inhibin B level. CONCLUSION: Intermittent ovarian activity in patients with POF is not a rare phenomenon. The predictive score described in this study may help us to identify POF patients most likely to recover intermittent ovarian function.