The long term effect of post-partum thyroid dysfunction (
PPTD) is not well established. This study was conducted to evaluate the outcome of permanent
hypothyroidism and factors predictive of thyroid dysfunction in a large cohort of women with
PPTD. In 164 women, treated with
levothyroxine for moderate and severe post- partum
hypothyroidism, the treatment was discontinued and subjects were followed-up for the recurrence of
hypothyroidism. Factors such as thyroid function tests, tyroid
peroxidase antibodies (TPOAb) titers, multiparity, history of autoimmune disorders, smoking habits, use of
oral contraceptives, family history of
thyroid disease,
goiter size and age at active phase of
PPTD were assessed. Seventy-one post-partum women without
PPTD were considered as control group. One hundred forty-eight women (90%) returned for follow-up, and 93 subjects (63%) developed
hypothyroidism with a median of 2 months after T4 withdrawal. Of factors predicting recurrence of
hypothyroidism, only age, and serum TSH and T3 concentrations at the time of occurrence of
PPTD entered the model in multiple stepwise regression analysis.
Hypothyroidism occurred earlier and more frequently in women aged 30 and over, as compared to younger ones (p < 0.01), hazard ratio 1.69. In 55 euthyroid subjects with history of
PPTD, serum TSH was significantly increased as compared to the control group (3.0 +/- 1.6 vs 0.8 +/- 0.5 mU/l, p < 0.001). These data, representing the largest cohort of women with
PPTD who have been followed, show that a significant proportion of women with moderate and severe
PPTD, in particular those aged 30 yr and over, develop recurrent
hypothyroidism. Proper follow-up of all women with
PPTD, the older ones in particular, is recommended.