Thyroid Dysfunction and Autoimmunity in Infertile Women

Abstract

A prospective study was undertaken in 438 women (ages, 32 +/- 5 years) with various causes of infertility, and in 100 age-matched (33 +/- 5 years) healthy parous controls with the aim of assessing the prevalence of autoimmune thyroid disease (AITD) and hitherto undisclosed alterations of thyroid function. Female origin of the infertility was diagnosed in 45% of the couples, with specific causes including endometriosis (11%), tubal disease (30%), and ovarian dysfunction (59%). Male infertility represented 38% and idiopathic infertility 17% of the couples. Overall, median thyrotropin (TSH) was significantly higher in patients with infertility compared to controls: 1.3 (0.9) versus 1.1 (0.8) mIU/L. Serum TSH above normal (>4.2 mIU/L) or suppressed TSH (<0.27 mIU/L) levels were not more prevalent in the infertile women than in controls. The prevalence of positive thyroid peroxidase antibody (TPO-Ab) was higher in all investigated women of infertile couples, compared to controls (14% vs. 8%), but the difference was not significant. However, in infertility of female origin, a significant higher prevalence of positive TPO-Ab was present, compared to controls: 18% versus 8%. Furthermore, among the female causes, the highest prevalence of positive antibodies was observed in women with endometriosis (29%). When thyroid antibodies were positive, both hypothyroidism and hyperthyroidism were more frequent in all women of infertile couples and in the women with a female infertility cause, compared to women in the same groups but without positive TPO-Ab. The present study shows that in infertile women, thyroid autoimmunity features are significantly more frequent than in healthy fertile controls and this was especially the case for the endometriosis subgroup.

Thyroid disorders and fertility

“…women compared to non-positive ones. 63 Previously menstrual disorders including particularly oligomenorrhea was reported as 50% in people with hyperthyroidism, but Krassas et al found that the rate is around 21.5 % in thyrotoxicosis. 4,64 Mean radioactive iodine (370 MBq) dose used in treating hyperthyroidism is curative and it doesn't affect gonadal performance.…”

“…In hypothyroidism, both the local effect of thyroid hormones on these receptors and prevention of release of pulsatile GnRH from hypothalamus lead to failure of healthy ovulation and prevent formation of high quality oocytes. 15 Concurrently, corpus luteum insufficiency due to disruption of LH release and hyperpolactineamia due to increased TRH release may also increase negative influences over normal menstrual cycle. 10,14 In hypothyroidism, even though elevated TSH may reduce sex hormone binding protein (SHBP), increasing free testosterone and estradiol level, total serum level of these hormones are usually low.…”

Hypothyroidism, Oxidative Stress and Reproduction

“…A positive correlation was found in early follicular phase between basal TSH, LH and T; moreover women with elevated TSH response to TRH had lower pregnancy rate than women with normal TSH response (Gerhard et al, 1991). In a controlled prospective study of 438 women with infertility of various origin, the median TSH levels were significantly higher than controls (Poppe et al, 2002). Moreover more frequent miscarriages were observed in women with higher basal TSH levels, irrespective of the presence of AITD (Raber et al, 2003).…”

The gonadotropins: Tissue-specific angiogenic factors?

“…Also, TSH is indirectly involved in endometrial pathology. A higher risk to develop endometriosis was reported in patients with associated thyroid autoimmunity (Poppe et al, 2002). Finally, hCG has been tested for impairing the painful endometrial symptoms (Huber et al, 2004).…”