CLINICAL ASPECTS OF RECURRENT POSTPARTUM THYROIDITIS

Background. Postpartum thyroiditis (PPT), characterized by transient h yperthyroidism and transient hypothyroidism. occurs in 5-9% of women. It is accompanied by the presence of circulating antithyroid peroxidas e antibodies (TPOAb) which have been associated with an increase in de pressive symptomatology compared with TPOAb-negative women. Aim. To as sess the frequency and nature of the syndrome in patients studied in d etail after more than one pregnancy, as there are only sparse data on recurrence of PPT. Method. Fifty-four patients were identified who had participated in at least two of three detailed postpartum studies of thyroid and psychiatric function during the past 12 years in the Caerp hilly and Cardiff regions of South Wales. They included two women who had had three pregnancies. All patients had been followed monthly post partum for at least six months, and 44 had been followed for 12 months . Results. Of the 13 patients who developed PPT after their first preg nancy, nine had a recurrence of dysfunction after a further pregnancy and four remained TPOAb positive. Of the 24 women who were euthyroid a nti-TPO positive after the first pregnancy, six developed thyroid dysf unction after a subsequent delivery, 14 remained antibody positive and euthyroid, while four underwent seroconversion and were antibody nega tive. The control group of 17 women were antibody negative after the f irst pregnancy; 16 remained negative after a further pregnancy and one became anti-TPO positive. The severity of PPT was slightly, but nor s ignificantly worse after the second recorded pregnancy (67% hypothyroi d versus 44% hypothyroid). Neither the maximum anti-TPO titre followin g the first pregnancy, nor the rise in titre during this period were p redictive of outcome after a subsequent pregnancy. Data from 26 women showed that recurrent depression was seen in 15.4%; a further six were depressed after the first pregnancy only and two during a further pos tpartum period. Conclusion. There was a 70% chance of developing recur rent PPT after a first attack, and a 25% risk even in women who were o nly anti-TPO positive without thyroid dysfunction during the first pos tpartum period. The recurrence of postpartum depression was not relate d to thyroid function. Patients noted to have thyroid dysfunction or j ust to be euthyroid but anti-TPO positive after pregnancy should be as sessed carefully after a subsequent pregnancy.