Endocrine Abstracts

Objective: To assess the immunological and ultrasound (US) characteristic of hypothyroidism and thyrotoxicosis developing during the postpartum period.

Patients and methods: 66 women with postpartum thyroid dysfunction (PPTD) (30 with hypothyroidism and 36 with thyrotoxicosis) without history of previous thyroid disorder were included. TRAb positive women were excluded from the study. Clinical evaluation was done, TSH, FT4, FT3, TPOAb, TgAb were measured, ultrasound examination of the thyroid gland was performed.

Results: Women who developed hypothyroidism were of similar age compared to women with thyrotoxicosis (29.83±4.13 vs 29.72±4.07 years, P=0.913). Women with hypothyroidism had significantly higher frequency of TPOAb positivity (P=0.038) compared with those with postpartum thyrotoxicosis. No differences in the presence of TgAb were found. On US examination hypothyroid women had larger thyroid volume (P=0.029) and higher grade of thyroid hypoechogenicity (P=0.004) compared to women who presented with thyrotoxicosis. In TPOAb positive hypothyroid women the levels of antibodies showed positive correlation with TSH (P=0.030) and negative relation with FT4 values (P=0.028). In TPOAb positive women with postpartum thyrotoxicosis TPOAb levels had positive correlation with thyroid volume (P=0.004), but not with hormonal parameters. In TPOAb negative thyrotoxic women however there was significant positive correlation between thyroid volume and FT4 (r=0.627, P=0.029) and FT3 (r=0.822, P=0.001) levels suggesting different stimulatory immune effects.

Conclusion: Hypothyroidism as an initial presentation of PPTD is characterized by more pronounced immunological and ultrasound abnormalities than postpartum thyrotoxicosis resulting in a relatively high risk of permanent thyroid dysfunction. In women with a history of PPTD regular follow up is justified.