Is an Elevation in Basal Follicle-Stimulating Hormone Levels in Unexplained Infertility Predictive of Fecundity Regardless of Age?

Abstract

Abstract.An elevation in follicle-stimulating hormone (FSH) levels is considered to reflect lowered ovarian function, resulting in poor fecundity in infertile women. However, it remains to be clarified whether or not the significance of FSH levels applies equally to all women irrespective of age. The objective of the present study is to compare basal FSH levels in infertile women who conceived or not after stratification by age. A total of 144 infertile women between ages 25 and 45 who underwent infertility treatment due to unexplained infertility in the University of Tokyo Hospital were included in the retrospective study. Subjects were divided by age into two groups, <38 (n=98) vs?38 (n=46) years, with ages ranging from 25 to 37, and from 38 to 45, respectively. Blood samples were collected in early follicular phase (day 4-6) for assessment of basal levels of LH, FSH, and PRL. In the older group, pregnant cases had significantly lower FSH levels (6.07±2.83 mIU/ml) than nonpregnant cases (9.60±3.67 mIU/ml), whereas no difference in basal FSH levels was observed between pregnant and nonpregnant cases in the younger group. Basal FSH levels of pregnant cases in the older group were significantly lower than those of pregnant cases in the younger group (8.26±2.95 mIU/ml).Basal LH and PRL levels were not related to fecundity in either group. Thus, an increase in basal FSH levels as a predictor of fecundity should be considered in the context of age.