Subclinical hypothyroidism and pregnancy

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Perinatal Medicine

Background:

• Pregnancy significantly impacts thyroid function, complicating hypothyroidism diagnosis.
• Overt hypothyroidism in pregnancy is linked to maternal and perinatal morbidity/mortality, with treatment improving outcomes.
• Subclinical hypothyroidism in pregnancy lacks definitive studies on treatment efficacy for fetal neurodevelopment.

Purpose of the Study:

• To review the challenges in diagnosing and treating subclinical hypothyroidism in pregnant women.
• To summarize current understanding of laboratory diagnosis and the lack of evidence for treatment benefits.
• To address the controversy surrounding screening and treatment recommendations for subclinical hypothyroidism in pregnancy.

Main Methods:

• Literature review and synthesis of existing studies and position statements.
• Analysis of the evidence regarding the link between subclinical hypothyroidism and fetal neurodevelopment.
• Evaluation of the current recommendations for screening and treatment in pregnant populations.

Main Results:

• No well-controlled, long-term studies demonstrate improved neurodevelopmental outcomes in offspring of mothers treated for subclinical hypothyroidism.
• Conflicting national guidelines exist regarding screening and treatment due to insufficient evidence.
• Current evidence suggests routine screening and treatment for subclinical hypothyroidism in pregnancy is unwarranted and experimental.

Conclusions:

• Obstetricians face pressure to screen and treat subclinical hypothyroidism despite uncertain benefits to offspring.
• Further large-scale clinical trials are needed to establish efficacy of treatment for neurodevelopmental outcomes.
• Until conclusive evidence emerges, routine screening and treatment of subclinical hypothyroidism during pregnancy should be avoided.