Hypothyroidism Complicating Pregnancy

EDITORIAL COMMENT: We accepted this paper for publication to remind readers that women who are receiving thyroxine replacement therapy for hypothyroidism require dose surveillance during pregnancy. The 2 cases diagnosed during pregnancy are of rare interest. For comparison of the incidence and perinatal results we reviewed the experience with hypothyroidism at the Mercy Hospital for Women, Melbourne, for the 10 years, 1980–1989. There were 51,407 confinements during this time, including 55 pregnancies in 23 women with hypothyroidism. In this series the only perinatal deaths were neonatal deaths ofl set of twins born at 24.3 weeks' gestation. Two of the 23 women had received treatment for thyrotoxicosis with radioactive iodine and 1 had had thyroidectomy performed for a benign tumour. None of these 23 women had hypothyroidism diagnosed during pregnancy although 2 had presented with infertility and conceived after diagnosis and treatment with thyroxine. Summary: In this report we describe 26 pregnancies complicated by hypothyroidism cared for over 6.5 years at AIIMS, New Delhi. In 2 women hypothyroidism was diagnosed during pregnancy; others were diagnosed before pregnancy and continued to receive thyroxine replacement therapy throughout pregnancy. The thyroxine treatment needed readjustment in 7 (26.9%) pregnancies to maintain euthyroidism. Maternal complications included anaemia (23.0%), pregnancy induced hypertension (26.9%), postpartum haemorrhage (7.7%), intrauterine growth retardation (15.4%), postdatism (30.8%), and deficient lactation (19.2%). Perinatal mortality was 3.9%. No case of stillbirth occurred probably because of intensive fetal monitoring arid timely termination of pregnancies on evidence of intrauterine fetal compromise. One neonatal death occurred due to fetal thyrotoxicosis. In these cases close surveillance during pregnancy is needed to maintain optimum thyroid hormone concentration, and intensive fetal monitoring is required to achieve a good perinatal outcome.