FSH levels in relation to hysterectomy and to unilateral oophorectomy

Objective: To examine the association between hysterectomy, unilateral ooph orectomy, and ovarian status, measured by FSH concentrations, in women aged 35-49 years. Methods: From the National Health and Examination Survey III, 1716 women ag ed 35-49 years were studied. Information on menopausal status, surgical his tory (hysterectomy, single or bilateral oophorectomy), smoking, and other c haracteristics was collected in a structured interview, height and weight w ere measured, and one blood sample was collected. We used logistic regressi on to analyze FSH concentration in relation to hysterectomy and oophorectom y, controlling for age, ethnicity, body mass index, smoking, education, nul ligravidity, and exercise. Results: Hysterectomy with unilateral oophorectomy was associated with an i ncreased prevalence of elevated FSH (above 20 IU/L) (adjusted odds ratio [O R] 2.4, 95% confidence interval [CI] 1.3, 4.6) compared with women who had not had hysterectomies or oophorectomies. Among women with two ovaries, hys terectomy was associated with increased prevalence of elevated FSH (adjuste d OR 1.5, 95% CI 1.0, 2.5). As a comparison of the effect size, the observe d association between hysterectomy and elevated FSH was smaller than the as sociation between FSH and current smoking (OR 2.0), a factor associated wit h a 1-2 year decrease in mean age at natural menopause. Conclusion: Although the differences in FSH levels were small, there was ev idence of elevated FSH in women who have had hysterectomies, even if at lea st,one ovary remained, (Obstet Gynecol 1999;94:969-72. (C) 1999 by The Amer ican College of Obstetricians and Gynecologists.).