From the Research
Thyroid-Stimulating Hormone (TSH) Levels Postpartum
The target range for TSH levels postpartum is not explicitly stated in the provided studies. However, the studies suggest the following:
- A TSH level of 4.0 μIU/mL is used as a threshold for subclinical hypothyroidism during pregnancy 1.
- TSH levels outside the range of 1.0-2.5 mU/L near childbirth are associated with postpartum thyroiditis (PPT) 2.
- A TSH level of 2.5 mU/L is used as a threshold for adjusting levothyroxine (LT4) treatment after delivery 3.
- A study found no differences in pregnancy outcomes after in vitro fertilization using a TSH cutoff of 2.5 mIU/L or 4.5 mIU/L 4.
Factors Affecting TSH Levels Postpartum
Some factors that affect TSH levels postpartum include:
- Gestational age at the time of subclinical hypothyroidism diagnosis 1
- Thyroid peroxidase antibodies (TPOAb) 1, 2
- TSH levels at diagnosis and during pregnancy 5, 2
- Levothyroxine (LT4) treatment and dosage 5, 3
Postpartum Thyroid Dysfunction
The studies suggest that:
- More than one-third of patients with subclinical hypothyroidism during pregnancy have persistent hypothyroidism after delivery 1
- The prevalence of postpartum thyroiditis (PPT) is comparable in women with previously known and newly diagnosed hypothyroidism 2
- TSH elevation at <8 gestational weeks is associated with PPT after delivery in women with known and newly diagnosed hypothyroidism 2