Endocrine Abstracts

About 5–10% of fertile women have anti-thyroid antibodies (AAT); however this prevalence is higher in infertile women. Few studies have been focused so far on the role of thyroid autoimmunity in the outcome of ART. Aims of our studies have therefore been: a) evaluate prevalence of thyroid antibodies in infertile women before ART; b) investigate whether AAT are more prevalent in a specific subset of infertile women; c) investigate the possible influence of AAT or thyroid dysfunction on the outcome of ART.

About 105 women (mean age 35.7+4.7) have been investigated; 11 subjects have been excluded from the study because of known thyroid diseases. The remaining 95 women have been divided according to the cause of infertility; 34% were idiopathic, 26.6% had a male factor, 6.4% had ovulatory disorders, 10% had endometriosis and 17.6% had tubal factor. TSH, FT4, Tg-Ab, TPO-Ab, TSHr-Ab (both stimulating and blocking) have been assayed before ovarian stimulation. AAT have been detected in 23 (24.4%) women, all of them being euthyroid except 1 subclinical hyperthyroid and 1 subclinical hypothyroid. The highest prevalence of AAT (27%) have been found in women with tubal factor infertility. Out of the 94 women, 85 have undergone ART (9 being non-responders to ovarian stimulation) and pregnancy was obtained in 23 cases; in 3 cases, however, precocious abortion has been observed. 6 out of these 23 were AAT positive (26%, 5 deliveries, 1 abortion). Amongst the 62 non-pregnant women, 15 were AAT positive (24.2%). TSH was not significantly different (1.6+0.95 mUI/l vs 1.8+1.04 mUI/l for pregnant and non-pregnant women respectively).

Nine women were positive for TSHr-Ab (in 7 cases without contemporary TPO- or Tg-Ab) 2 of them becoming pregnant. According to TSH value 70 (82.3%) women had a value below 2.5 mUI/l; 21 (30%) of them became pregnant but 2 had precocious abortion. Fifteen (17.7%) women had TSH value above 2.5 mUI/l (but still within the normal range); 3 (20%) became pregnant but 1 had precocious abortion.

Our data suggest; a) higher prevalence of AAT in infertile women; b) AAT were more frequently associated to tubal factor infertility; c) more cases are needed in order to draw final conclusion about the possible interference of within-the-normal-range TSH value above 2.5 mUI/l with the positive outcome of ART.