Medenica S, Nedeljkovic O, Radojevic N, Stojkovic M, Trbojevic B, Pajovic B
Department of Endocrinology, Clinical Center of Montenegro, Faculty of Medicine University of Montenegro, Podgorica, Montenegro.
Eur Rev Med Pharmacol Sci. 2015;19(6):977-87.
Thyroid disease is the second most common endocrine condition in women of childbearing age. Thyroid hormones are involved in control of menstrual cycle and in achieving fertility affecting the actions of follicle-stimulating hormone and luteinizing hormone on steroid biosynthesis by specific triiodothyronine sites on oocytes; therefore, affect all aspects of reproduction. It remains controversial if pregnant women should be screened for thyroid dysfunction. Purpose of this review was to examine recent studies on the assessment of thyroid dysfunction in pregnancy, its treatment and newly perspective of thyroid autoimmunity in pregnant euthyroid women in achieving fertility.
An electronic search was conducted using the internet medical databases: Medline/PubMed, EMBASE, EBSCO, and the Cochrane library.
Thyroid gland faces great challenge in pregnancy when many hormonal changes occur. Precondition for normal follicular development and ovulation is pulsate gonadothropin realizing hormone secretion. Thyroid dysfunction in pregnancy is classified as forms of hypothyroidism (positivity of thyroid autoantibody, isolated hypothyroidism, and subclinical or overt hypothyroidism), hyperthyroidism, and autoimmune disease, but also thyroid nodules and cancer, iodine insufficiency and postpartum thyroiditis. These conditions can cause adverse effects on mother and fetus including pregnancy loss, gestational hypertension, or pre-eclampsia, pre-term delivery, low birth weight, placental abruption and postpartum hemorrhage. There is an evidence that thyroid autoimmunity, in thyroid dysfunction adversely affects conception and pregnancy outcomes, but it is unclear what impact has isolated eumetabolic thyroid autoimmunity in achieving fertility, especially in women undergoing in vitro fertilization. Treatment of euthyroid pregnant women with positive thyroid peroxides antibodies is still controverse, but not few studies show that levothyroxine substitution is able to lower the chance of miscarriage and premature delivery.
Further randomized trials are needed to expand our knowledge of physiologic changes in thyroid function during the pregnancy and to reveal mechanisms by which thyroid autoimmunity in euthyroid women affect fertility, especially the success of assisted reproductive technology in achieving the same and validity of levothyroxine administration in thyroid autoimmunity positive women.
甲状腺疾病是育龄女性中第二常见的内分泌疾病。甲状腺激素参与月经周期的调控以及生育过程，影响促卵泡激素和黄体生成素通过卵母细胞上特定的三碘甲状腺原氨酸位点对类固醇生物合成的作用；因此，会影响生殖的各个方面。孕妇是否应筛查甲状腺功能障碍仍存在争议。本综述的目的是研究近期关于孕期甲状腺功能障碍评估、其治疗以及甲状腺自身免疫在甲状腺功能正常的孕妇生育方面的新观点的研究。
利用互联网医学数据库进行电子检索：Medline/PubMed、EMBASE、EBSCO和Cochrane图书馆。
孕期甲状腺面临巨大挑战，此时会发生许多激素变化。正常卵泡发育和排卵的前提是促性腺激素释放激素的脉冲式分泌。孕期甲状腺功能障碍分为甲状腺功能减退形式（甲状腺自身抗体阳性、孤立性甲状腺功能减退、亚临床或显性甲状腺功能减退）、甲状腺功能亢进、自身免疫性疾病，还有甲状腺结节和癌症、碘缺乏以及产后甲状腺炎。这些情况会对母亲和胎儿造成不良影响，包括流产、妊娠期高血压或先兆子痫、早产、低出生体重、胎盘早剥和产后出血。有证据表明，甲状腺功能障碍中的甲状腺自身免疫会对受孕和妊娠结局产生不利影响，但尚不清楚孤立的甲状腺功能正常的甲状腺自身免疫在生育方面有何影响，尤其是对接受体外受精的女性。对甲状腺过氧化物抗体阳性的甲状腺功能正常的孕妇进行治疗仍存在争议，但不少研究表明左甲状腺素替代能够降低流产和早产的几率。
需要进一步的随机试验来扩展我们对孕期甲状腺功能生理变化的认识，并揭示甲状腺功能正常的女性的甲状腺自身免疫影响生育的机制，尤其是辅助生殖技术在实现这一点上的成功率以及左甲状腺素在甲状腺自身免疫阳性女性中的有效性。
