Stuckey BGA, Kent GN, Ward LC, Brown SJ and Walsh JP
Postpartum thyroid dysfunction and the longterm risk of hypothyroidism: results from a 12-year follow-up study of women with and without postpartum thyroid dysfunction
Clinical Endocrinology (2010) 73, 389–395
Abstract
Background. The long-term risk of hypothyroidism following postpartum thyroid dysfunction (PPTD) is uncertain. Most previous studies have been small, short term or have lacked a control group.
Objective. To ascertain the long-term risk of hypothyroidism in women following PPTD.
Design and participants. A 12 year longitudinal study of 409 women (including 71 with PPTD) who previously participated in a PPTD prevalence study.
Measurements. The primary outcome measure was hypothyroidism (defined as TSH greater than 4 mU/L or on thyroxine replacement) at follow-up. Outcomes in women with and without PPTD were compared by logistic regression. Receiver operating characteristic analysis was used to determine the optimal cut-off for baseline TSH as a predictor of hypothyroidism in the cohort.
Results. At follow-up, hypothyroidism was present in 27 of 71 women who had PPTD at baseline (38%) and 14 of 338 women without PPTD (4%). From multivariate analysis, odds ratios (with 95% confidence intervals) for hypothyroidism were – 4.8 (1.6, 14.1) for PPTD; 8.2 (2.8, 24.6) for positive TPOAb ; 9.7 (2.6, 37.0) for the hypothyroid phase of PPTD and 51.4 (19.2, 137.5) for hypothyroid PPTD with positive TPOAb. A baseline TSH above 2.6 mU/L was the optimal cut-off for predicting hypothyroidism (sensitivity 76%, specificity 86%).
Conclusions. PPTD is a strong predictor of hypothyroidism in the long-term. Women who present with postpartum hypothyroidism or have positive TPOAb are at particularly high risk, suggesting that close long-term follow-up is advisable if thyroxine replacement is not instituted at an early stage.
Tags: hypothyroidism, postpartum, pregnancy, thyroid