A systematic review and meta-analysis of the association between Hashimoto's thyroiditis and ovarian reserve

Currently, whether Hashimoto's thyroiditis decreases ovarian reserve is not clearly known, given the conflicting findings from previous studies. This study was conducted to systematically review and summarize the association of Hashimoto's thyroiditis (HT) with ovarian reserve.

Studies investigating ovarian reserve in women with HT and the incidence of HT in women with premature ovarian aging (POA) were searched in major electronic databases. Pre-specified subgroup analyses were performed in terms of agedistribution and thyroidfunction.

A total of 935 studies were retrieved from which 30 were included in the meta-analysis and 5 were finallyselectedfor detailed review. Overall, no statistically significant difference in ovarian reserve parameters (AMH, AFC, FSH, E2) between females with HT and the controls. In subgroup meta-analyses, reproductive aged women with HT had a statistically significant reduction in AMH (SMD -0.35; 95% CI: -0.51, -0.19; P＜0.0001; I² = 52%), AFC (MD -0.43; 95% CI: -0.56, -0.30; P＜0.00001; I² = 62%), and increase in basal FSH (SMD 0.1; 95% CI: 0.01, 0.19; I² = 19%; P = 0.04) compared with age matched controls. Furthermore, POA inreproductive aged women wasassociatedwith higher frequency ofpositiveTPOAb (OR 2.26, 95% CI: 1.31-3.92, p = 0.004) but not positive TgAb(OR 3.17, 95% CI: 0.89-11.38, p = 0.08).

These bidirectional associations suggested that reproductive aged women with HT have a significantly higher risk of diminished ovarian reserve.