Thyroid hormone treatment among pregnant women with subclinical hypothyroidism: US national assessment.

ABSTRACT:

Objective

 To estimate the effectiveness and safety of thyroid hormone treatment among pregnant women with subclinical hypothyroidism.

Design

 Retrospective cohort study.

Setting

 Large US administrative database between 1 January 2010 and 31 December 2014.

Participants

 5405 pregnant women with subclinical hypothyroidism, defined as untreated thyroid stimulating hormone (TSH) concentration 2.5-10 mIU/L.

Exposure

 Thyroid hormone therapy.

Main outcome measure

 Pregnancy loss and other pre-specified maternal and fetal pregnancy related adverse outcomes.

Results

 Among 5405 pregnant women with subclinical hypothyroidism, 843 with a mean pre-treatment TSH concentration of 4.8 (SD 1.7) mIU/L were treated with thyroid hormone and 4562 with a mean baseline TSH concentration of 3.3 (SD 0.9) mIU/L were not treated (P<0.01). Pregnancy loss was significantly less common among treated women (n=89; 10.6%) than among untreated women (n=614; 13.5%) (P<0.01). Compared with the untreated group, treated women had lower adjusted odds of pregnancy loss (odds ratio 0.62, 95% confidence interval 0.48 to 0.82) but higher odds of preterm delivery (1.60, 1.14 to 2.24), gestational diabetes (1.37, 1.05 to 1.79), and pre-eclampsia (1.61, 1.10 to 2.37); other pregnancy related adverse outcomes were similar between the two groups. The adjusted odds of pregnancy loss were lower in treated women than in untreated women if their pre-treatment TSH concentration was 4.1-10 mIU/L (odds ratio 0.45, 0.30 to 0.65) but not if it was 2.5-4.0 mIU/L (0.91, 0.65 to 1.23) (P<0.01).

Conclusion

 Thyroid hormone treatment was associated with decreased risk of pregnancy loss among women with subclinical hypothyroidism, especially those with pre-treatment TSH concentrations of 4.1-10 mIU/L. However, the increased risk of other pregnancy related adverse outcomes calls for additional studies evaluating the safety of thyroid hormone treatment in this patient population.

SUBMITTER: Maraka S 

PROVIDER: S-EPMC5266622 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature