Perinatal outcome in hypothyroid pregnancies.

OBJECTIVE

To relate hypothyroidism to perinatal outcome.

METHODS

A cohort of 68 hypothyroid patients with no other medical illnesses was divided into two groups according to the initial thyroid function tests. The first group had 23 women with overt hypothyroidism, and the second had 45 subjects with subclinical hypothyroidism. We sought to identify the pregnancy outcomes of gestational hypertension, low birth weight, fetal death, congenital anomalies, maternal anemia, and postpartum hemorrhage.

RESULTS

Gestational hypertension--namely, eclampsia, preeclampsia, and pregnancy-induced hypertension--was significantly more common in the overt and subclinical hypothyroid patients than in the general population, with rates of 22, 15, and 7.6%, respectively. In addition, 36% of the overt and 25% of the subclinical hypothyroid subjects who remained hypothyroid at delivery developed gestational hypertension. Low birth weight in both overt and subclinical hypothyroid patients was secondary to premature delivery for gestational hypertension. Except for one stillbirth and one case of clubfeet, hypothyroidism was not associated with adverse fetal and neonatal outcomes.

CONCLUSION

Normalization of thyroid function tests may prevent gestational hypertension and its attendant complications in hypothyroid patients.