Outcome of thyroid dysfunction in pregnancy in Mashhad, Iran

ABSTRACT

Thyroid disorders are common in women during pregnancy, when the excess or deficiency of maternal thyroid hormones has been associated with adverse health outcomes for both the mother and child. This study performed to study the prevalence of thyroid disorders and its effect on pregnancy outcomes in pregnant women. In 500 pregnant women in first trimester of pregnancy enrolled for the study, Serum Thyrotropin [TSH], Free T4 [FT4], and Free T3 [FT3] were measured by high-sensitive radioimmunoassay. Overt hyperthyroidism was diagnosed when both TSH was suppressed and FT4 or FT3 were elevated. Sub-clinical hyperthyroidism was diagnosed when TSH was suppressed with normal FT4 and FT3. The diagnostic criteria for overt hypothyroidism was TSH> 4 mU/L accompanied by decreased FT4, and for subclinical hypothyroidism a TSH> 4 mU/L with normal FT4 level. Those with thyroid disorders were referred to an endocrinologist for medical treatment and all subjects were followed until delivery. Mean age of women was 24.5 +/- 4.9 years. Hypothyroidism, both subclinical [7.4%] and overt [2.4%], was found in 49 [9.8%] women. Overt hyperthyroidism found in 3 [0.6%] and subclinical hyperthyroidism in 21 [4.2%] women and was considered a physiologic change of pregnancy. On follow up, 19 women [3.8%] had preterm labor, and 25[5%] women developed pre-eclampsia. There was no significant difference in the incidence of preterm labor and pre-eclampsia in pregnant women with or without thyroid dysfunction. Normal neonates were born to 498 women, while 2 [0.4%] euthyroid mothers delivered fetuses with anomalies. Although thyroid dysfunction is common in pregnant women, the prevalence of complications is not higher in patients with thyroid dysfunction, as compared to normal euthyroid controls