The effects of screening and intervention of subclinical hypothyroidism on pregnancy outcomes: a prospective multicenter single-blind, randomized, controlled study of thyroid function screening test during pregnancy

Abstract

Purpose: To evaluate the effect of subclinical hypothyroidism (SCH) screening and intervention on pregnancy outcomes and explore the significance of thyroid function during early pregnancy.

Methods: Pregnant women were recruited from Peking Union Medical College Hospital (screening group for measuring thyroid function and thyroid antibody in early pregnancy) and Haidian Maternal & Child Health Hospital (control group whose serum was stored and measured shortly after delivery) from July 2011 to December 2012. Thyrotropin levels 2.5–10 mIU/L and free T4 levels in normal range were considered SCH. Some of the screening group were treated with levothyroxine and adjusted. The others did not take medicine but kept a regular follow-up visit to doctors after antenatal clinic. The pregnancy outcomes and complications were compared.

Results: 1671 women (675 in screening group and 996 in control group) were recruited. 419 (167 from screening group) women was diagnosed as SCH. In screening group, 105 SCH and 4 hypothyroid women received thyroid hormone replacement therapy. The miscarriage and fetal macrosomia risks were lower, and cesarean was higher in screening group than control.

Conclusion: Screening and intervention of SCH can significantly reduce the incidence rate of miscarriage.

Keywords:

• Pregnancy outcome
• subclinical hypothyroidism
• thyroid function tests

Declaration of interest

All the authors declare that they have no conflict of interest. This study was sponsored by Beijing government excellent person sponsor program (2012D009008000003) and Beijing capital clinical trial (Z111107058811025).