Bachimanchi B, et al. - Among premenopausal women with overt hypothyroidism (thyroid-stimulating hormone > 15 IU/L) in the early follicular phase of their natural menstrual cycles or after a progesterone challenge for gonadotropins, estradiol (E₂), and prolactin (PRL), researchers studied the effect of adequate thyroid hormone replacement on the hypothalamo-pituitary-gonadal axis. Forty premenopausal hypothyroid women were assessed at baseline and ≥ 2 months after adequate thyroxine (T₄) replacement. No changes were noted in the levels of the gonadotropins luteinizing hormone and follicle-stimulating hormone. According to findings, hypothyroidism may be associated with a reversible partial suppression of the hypothalamo-pituitary-gonadal axis in premenopausal women with a mild PRL elevation demonstrated by lower E₂. They observed that hypothyroidism treatment improves the estrogen level and lowers the PRL level.