Hypothyroidism in Pregnancy (ATA)

Serum TSH (mIU/L)

mIU/L

Trimester

Note: The preferred total TSH upper limit is trimester-specific (approx 2.5 for 1st trimester). TSH targets change during pregnancy due to the stimulating effects of hCG on the thyroid.

Guidelines & Evidence

Verified

Last Review: 2026

When to Use

When to Screen

Women Planning Pregnancy or already pregnant with symptoms of hypothyroidism.

History of thyroid disease or previous thyroid surgery.

Age > 30 years.

History of recurrent miscarriage or preterm delivery.

Type 1 Diabetes or other autoimmune disorders.

How it Works

TSH Management (2017 Guidelines)

TSH Range (mIU/L)	TPO Antibody	Recommendation
> 4.0	Any	Treat (Strong)
2.5 – 4.0	Positive	Treat (Recommended)
2.5 – 4.0	Negative	Consider Treat (Weak)
< 2.5	Any	Monitor / No treatment

Last Comprehensive Review: 2026

Recent Journal Updates

PLOS MedicineJul 21, 2026

Adverse pregnancy outcomes and long-term risk of peripheral artery disease: A cohort study

Clinical Context

We think this might be relevant to the clinical guidance for Hypothyroidism in Pregnancy (ATA).

British J Clinical PharmacologyJul 16, 2026

A British Pharmacological Society Position Statement on Medications in Pregnancy and Lactation

Clinical Context

We think this might be relevant to the clinical guidance for Hypothyroidism in Pregnancy (ATA).

BJOGJul 16, 2026

Hypertensive Disorders of Pregnancy and the Long‐Term Risk of Maternal Retinal and Ophthalmic Disease: A Systematic Review and Meta‐Analysis

Clinical Context

We think this might be relevant to the clinical guidance for Hypothyroidism in Pregnancy (ATA).

Hypothyroidism in Pregnancy (ATA)

When to Use

When to Screen

How it Works

TSH Management (2017 Guidelines)

Clinical Pearls

Why TSH 2.5?

Levothyroxine Dosing

The Evidence

Primary Source

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.

Recent Journal Updates

Hypothyroidism in Pregnancy (ATA)

When to Use

When to Screen

How it Works

TSH Management (2017 Guidelines)

Clinical Pearls

Why TSH 2.5?

Levothyroxine Dosing

The Evidence

Primary Source

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.

Recent Journal Updates