THYROID AND OVARIAN-FUNCTION IN INFERTILE WOMEN

The aim of this study was to examine more closely the interaction between thyroid function and pituitary - ovarian axis in infertile women. In 185 infertile women without clinical signs of thyroid dysfunction, TRH-tests (TSH basal and 30 min after 200-mu-g TRH i.v.) were performed in the early follicular phase in addition to routine hormonal checks (gonadotrophins, oestradiol, DHEAS, testosterone, prolactin). The women were classified as euthyroid (n = 74; TSH stim 5-20 mU/l), latent hyperthyroid (n = 31; TSH stim < 5 mU/l), and preclinical hypothyroid (n = 80; TSH stim > 20 mU/l). From frozen serum, the following determinations were performed: TSH IRMA, laevothyroxine (T4), thyroxine binding globulin (TBG), microsomal (Mab) and thyroglobulin (Tab) antibodies. Various correlations between the thyroid parameters and the pituitary - ovarian axis were demonstrated. With increasing TBG concentrations, the interval between menses decreased. Overall and spontaneous pregnancy rates were highest in women with normal (< 75th perc.) basal and stimulated TSH, high (> 75th perc.) T4 and low (< 25th perc.) Mab. Women with normal Tab or high TBG experienced the highest delivery rate (77 versus 30%), while in women with low Tab or high Mab abortion and tubal pregnancies were most frequent. As only 25 women exhibited elevated Mab (> 500 U/ml) or Tab (> 200 U/ml) which correlated with elevated TSH and normal T4, the routine determination of thyroid antibodies was not necessary. The TRH-test, however, should be included in infertility work-up.