Thyroid
New guidance reshapes thyroid care before, during, and after pregnancy
Clinical Takeaway: Avoid reflex treatment of mild thyroid abnormalities in pregnancy—confirm persistence, prioritize TSH-guided decisions, and target therapy to those most likely to benefit.
The American Thyroid Association (ATA) has released its 2026 update to guidelines on thyroid disease across preconception, pregnancy, and postpartum care, incorporating nearly a decade of new evidence and shifting toward a more conservative, individualized treatment approach.
“Our goal was to prioritize clinically meaningful interventions and reduce unnecessary treatment where evidence shows no benefit,” the authors note, emphasizing a move toward “individualized patient care with shared decision-making.”
Central to the update is a recalibration of when, and whether, to treat subclinical disease and thyroid autoimmunity. The guideline underscores that many mild abnormalities normalize on repeat testing and that overtreatment may carry risks without clear benefit.
Drug-related guidance remains a cornerstone, particularly around levothyroxine (LT4), antithyroid drugs (ATDs), and iodine supplementation, with clearer thresholds, timing considerations, and safety signals.
What’s changed
Less aggressive LT4 use in subclinical hypothyroidism:
- Treatment no longer guided by TPOAb status alone
- Consider LT4 only for early (first-trimester) cases; do not treat after first trimester
- Confirm persistence of mild abnormalities before starting therapy
No LT4 for euthyroid thyroid autoimmunity:
- High-quality trials show no benefit of LT4 in euthyroid TPOAb-positive women (infertility or pregnancy)
- Routine therapy and adjunctive treatments (selenium, steroids, IVIG) not recommended
Repeat testing emphasized before treatment:
- Many mild overt or subclinical cases normalize within weeks
- Confirmatory testing recommended prior to initiating LT4, especially if TSH <6 mU/L
Refined LT4 strategy in pregnancy:
- Target TSH <2.5 mU/L
- Expect 25%–50% dose increase during pregnancy
- Avoid T3-containing therapies (e.g., liothyronine, desiccated thyroid)
Antithyroid drug updates:
- Propylthiouracil (PTU) preferred in early pregnancy due to lower teratogenic risk vs methimazole
- Consider discontinuing ATDs early in pregnancy in low-risk patients
- Treat overt hyperthyroidism but not gestational transient thyrotoxicosis
Iodine recommendations strengthened:
- Target 250 mcg/day intake in pregnancy and lactation
- Start 150 mcg/day supplementation preconception in at-risk women
- Avoid excess (>500 mcg/day) due to fetal thyroid dysfunction risk
Screening approach refined:
- Continue risk-based testing, not universal screening
- Remove low-yield risk factors (e.g., age, BMI) and refine high-risk criteria
Summary
The 2026 ATA guideline marks a shift away from broad treatment toward precision management of thyroid dysfunction in pregnancy. Overt hypothyroidism continues to warrant prompt LT4 therapy, but clinicians are urged to verify mild abnormalities before initiating treatment and to weigh risks carefully in subclinical disease.
Hyperthyroidism management similarly balances maternal and fetal risks, with clear preference for PTU early in pregnancy and tighter criteria for when ATDs can be stopped. Meanwhile, iodine sufficiency remains a public health priority, with stronger supplementation guidance beginning before conception.
Overall, the update emphasizes judicious use of medications, improved diagnostic accuracy, and individualized care pathways—aimed at optimizing outcomes while minimizing unnecessary interventions.
Source: Korevaar TIM, et al. (2026, May 31). Thyroid. American Thyroid Association 2026 Guidelines for Thyroid Disease in Preconception, Pregnancy, and Postpartum