Normal vitamin D and low free estradiol levels in women on enzyme-inducing antiepileptic drugs

► Reproductive hormones, bone markers, bone density and loss were evaluated in women with epilepsy on antiepileptic drugs. ► Serum calcium (P < 0.001) and estrone (P < 0.001) were lower in women on enzyme inducing antiepileptic drugs. ► SHBG was higher (P < 0.001) and percent free estradiol was lower (P < 0.001) in women on enzyme inducing antiepileptic drugs.► Women with higher SHBG and lower free estradiol had more total hip bone loss and a trend toward more lumbar bone spine loss. ► Lower estrogen levels may contribute to bone loss in premenopausal women with epilepsy on antiepileptic drugs.