The Prevalence and Fetal and Maternal Outcome of Overt and Subclinical Hypothyroidism among Pregnant Women; A Cross-sectional Study

Maternal thyroid dysfunction during pregnancy and its relationship with pregnancy outcomes has been under consideration in last decades. Hypothyroidism, especially subclinical hypothyroidism, is the most common type of thyroid dysfunction among women in reproductive age. We aimed to evaluate the prevalence and maternal/fetal outcomes of these two conditions among Iranian pregnant women.

This cross-sectional study was conducted between January and July 2016 at Baqiyatallah hospital, Tehran, Iran. All pregnant women attending to Baqiyatallah Obstetrics and Gynecology clinic during study period were assessed for eligibility. Demographic information as well as information on parity, repeated abortion, history of infertility, size of thyroid and history of autoimmune diseases were recorded in a pre-designed checklist. TSH and T4 levels were measured by Chemiluminescence method and recorded in related forms.

Eventually 500 patients with a mean age of 27.77±4 years underwent analysis. Thyroid dysfunctions had a prevalence of 30.2% (151 cases). Of this proportion 143 patients (28.6%) had hypothyroidism from which 56(11.2%) patients had clinical and 59(11.8%) had subclinical hypothyroidism. In this study, 258 individuals had deliveries with one abortion in euthyroid and one in low-TSH group.

In conclusion our findings showed that hypothyroidism has a prevalence of 28.6% among Iranian pregnant women attending to our hospital. Also we found that subclinical hypothyroidism is more prevalent than overt hypothyroidism. The results showed that thyroid dysfunction is more prevalent in infants with maternal impaired thyroid function tests.