Thyroid Dysfunction in the First Gestational Trimester and Perinatal Outcomes

Background: During pregnancy, the thyroid metabolism dysfunctions might result in negative fetal-maternal outcomes, such as preterm delivery and miscarriage. It might also cause a long-term impact on childhood neuropsychomotor development. Objective: Identify and analyse thyroid metabolic dysfunction prevalence in pregnant women during the first gestational trimester. Methods: In a cohort study, a group of women with less than 12 weeks of pregnancy who were registered in prenatal care at Basic Health Units in an Amazon capital city were interviewed and examined. Follow-ups on the products of the conception were taken during the first six months after birth. All the pregnant women signed The Informed Consent. 5mL of blood were collected for complete blood count, lipid profile and hormone dosage (free T4, TSH, TSH anti-receptor, anti-peroxidase and anti-thyroglobulin antibodies). For thyroid dysfunction classification, it was used the criteria adopted by the American Thyroid Association (ATA). Results: Sixty-two pregnant women have been included in the study so far, with no reports of previous pathologies. The prevalence of thyroid dysfunctions was of 22,5% (n=14/62), discriminated as follows: 12,9% of subclinical hypothyroidism (8/62), 3,2% (2/62) of clinical hypothyroidism, 4,8% of subclinical hyperthyroidism (3/62) and 1,6% (1/62) of clinical hyperthyroidism. From those who had thyroid dysfunction, 22,2% had also clinical history of miscarriages and 61,1% were primigesta women. Only 16,7% were multipara with no miscarriage history. All of the pregnant women were treated and returned for prenatal care. Among those who had already given birth (64,5%) there were no consequences for the newborn (pediatric follow-up). Conclusion: Due to the significant negative outcomes for both mother and child, thyroid dysfunction during pregnancy must be regarded as a worldwide concern. For an early diagnosis, treatment and, consequently, a reduction of the still high miscarriage rates, the thyroidal hormone dosages should be stimulated in all countries, as prenatal care public routine, even for women that did not present clinical signs of dysfunction.