Postpartum Follow-up in Women Diagnosed with Subclinical Hypothyroidism during Pregnancy

Management guidelines about the thyroid disease in pregnancy are silent about the postpartum course of new onset subclinical hypothyroidism (SCH). Hence, we analyzed the 2 years outcome of SCH diagnosed during pregnancy.

We conducted this retrospective study using the medical records of patients with new onset SCH during pregnancy between 2010 and 2013 (n = 718). Patients who stopped their levothyroxine after delivery with a 2-year follow-up record were included. We excluded patients with known thyroid disorders and continuous use of drugs that affect the thyroid results. The patients were divided into two groups (Group 1 - euthyroid and Group 2 - hypothyroid) based on the final outcome after 2 years. The data were analyzed using appropriate statistical methods and a P < 0.05 was considered statically significant.

A total of 559 (77.8%) women stopped levothyroxine after delivery, and the final follow-up data were available for 467 patients only. At the end of 2 years, 384 (82.2%) remained euthyroid, and the remaining 83 (17.8%) developed hypothyroidism. SCH and overt hypothyroidism were seen in 22 and 61 patients, respectively. Group 2 patients had higher mean age (25.5 vs. 23.6 years), goiter (51 vs. 2%), initial thyroid stimulating hormone (7.9 vs. 5.1 μIU/mL), and thyroid antibody positivity (76 vs. 13%) (P < 0.001).

The majority of patients with SCH during pregnancy remain euthyroid after delivery. Advanced age, goiter, positive family history, and thyroid autoimmunity increase the future risk of hypothyroidism in patients with SCH diagnosed during pregnancy.