Endocrine Abstracts

Introduction: Thyroid pathology is common in women of reproductive age. Evaluation of thyroid function is classically recommended in cases of recurrent abortion. The presence of dysthyroidism or antithyroid antibodies increases the risk of abortion. We report two observations of hypofertility related to thyroid pathology and discuss the therapeutic course.

Case 1: A 33 year old woman was referred for etiological investigation of recurrent abortion. She presented 3 successive abortions at 6, 8 and 12 weeks of amenorrhea respectively. The etiological investigation concluded to a Hashimoto’s thyroiditis with FT4: 11.1 m IU/l and TSH: 13.46 m IU/l and strongly positive anti TPO antibodies. The diagnosis of latent hypothyroidism was retained. The patient was able to carry a pregnancy to term with a healthy baby under hormone replacement therapy.

Case report 2: A 35-year-old woman was referred for etiologic investigation of recurrent abortion. She had two in-utero fetal deaths at 12 weeks and 30 weeks of amenorrhea respectively. The thyroid workup was normal but the anti TPO antibodies were strongly positive. In the absence of a therapeutic consensus on how to deal with repeated abortions associated with positive antithyroid antibodies, our approach was to abstain with monitoring of the thyroid balance. The evolution was marked by the subsequent occurrence of two abortions and a patent hypothyroidism requiring hormone replacement. Hypofertility was attributed to a purely gynecological cause.

Discussion: Hypothyroidism is recognized as a cause of hypofertility. Several mechanisms have been put forward to explain the dys- or anovulation related to this pathology; these are essentially hyperprolactinemia, disturbance of sex steroids, etc. If not substituted, hypothyroidism exposes the patient to miscarriage, and fetal death in utero. Regarding thyroid antibody positivity in clinically euthyroid women, the majority of studies have found that the miscarriage rate is doubled in these women compared to women without antibodies. The hypothesis is that the presence of anti-thyroid antibodies reflects a more generalized activation of the immune system. In this context, several studies report a decrease in the percentage of spontaneous miscarriages and preterm deliveries during treatment with immunoglobulins and levothyroxine in euthyroid women with anti-TPO antibodies.

Conclusion: The management of hypothyroidism during pregnancy is currently well codified, allowing the prevention of spontaneous miscarriage as shown in the first observation. However, the management of thyroid antibody positivity in clinically euthyroid women is still not consensual and the imputability of these antibodies remains to be demonstrated on large cohorts.