An Advantageous Role of Spectral Doppler Sonography in the Evaluation of Thyroid Dysfunction During the Postpartum Period.

OBJECTIVES: To evaluate the diagnostic value of spectral Doppler sonography in women with thyroid dysfunction during the first postpartum year.

METHODS: This prospective observational clinical study included 83 consecutive untreated women: 32 with hyperthyroid postpartum thyroiditis, 32 with hypothyroid postpartum thyroiditis, and 19 with Graves disease, which first appeared within 12 months after delivery. Thyrotropin, free thyroid hormones, thyroid peroxidase antibodies, thyroglobulin antibodies, and thyrotropin receptor antibodies were measured. With a 7.5-MHz linear transducer, we measured the thyroid volume and peak systolic velocity (PSV) at the level of intrathyroid arteries.

RESULTS: Hyperthyroid postpartum thyroiditis appeared significantly earlier (mean ± SD, 4.4 ± 1.9 months after delivery) than hypothyroid postpartum thyroiditis (6.5 ± 2.1 months) and Graves disease (7.2 ± 2.7 months; P< .001). The thyroid volume in hyperthyroid postpartum thyroiditis (9.7 ± 6.3 mL) was significantly lower than in hypothyroid postpartum thyroiditis (14.7 ± 10.2 mL; P = .030) and Graves disease (19.4 ± 10.2 mL; P< .001). The PSV in hyperthyroid postpartum thyroiditis (9.4 ± 3.4 cm/s) was significantly lower than in hypothyroid postpartum thyroiditis (14.4 ± 3.9 cm/s; P < .001) and Graves disease (19.8 ± 7.0 cm/s; P < .001). With a cutoff level of 15 cm/s, the sensitivity and specificity of the PSV as a predictor of the correct diagnosis in hyperthyroid postpartum women were 94.7% and 96.8%, respectively. A multinomial logistic regression revealed PSV and the time after delivery at which the disorders presented as independent predictors of the differentiation between hyperthyroid postpartum thyroiditis and Graves disease (P = .003; P = .022).

CONCLUSIONS: Spectral Doppler sonography was shown to be a useful and accurate method for thyroid dysfunction evaluation during the postpartum period.