Pregnancy outcomes and thyroid dysfunction: preterm birth risk assessment

Abstract

Introduction. Subclinical hypothyroidism occurs in 2–3% of pregnant women and is often associated with pregnancy complications, including preterm birth.Aim – to study correlations between thyroid dysfunction and pregnancy outcomes.Materials and methods. 64 clinical cases of managing pregnant women in the Perinatal Center (Tyumen) were analyzed for 2017– 2021: 28 women with thyroid-stimulating hormone (TSH) > 2.5 mU/l, 36 women with TSH ≤ 2.5 mU/l) during the entire period of pregnancy. Quantitative features are described by absolute and relative (percentage) indicators. The probability of outcome depending on the presence of a clinical-amnestic factor was assessed by determining the relative risk (RR) and 95% confidence interval (CI). The level of statistical significance in testing the null hypothesis is p < 0.05.Results. There were no differences in pregnant women with and without subclinical hypothyroidism when considering such medical and social factors as age, marital status, work, education, nicotine addiction, obesity, kidney disease. An increased risk of preterm delivery was found in patients with a TSH level > 2.5 mU/l: RR 1.41 (0.59–3.37), especially against the background of a positive test for antibodies to thyroperoxidase: RR 1.63 (0.62–4.28). In the absence of treatment, the risk of early delivery, preterm birth, preeclampsia was revealed.Conclusions. A universal approach to determining the threshold values of TSH for the diagnosis of subclinical hypothyroidism in pregnant women, to the need and tactics of its treatment has not been developed. Diseases of the thyroid gland are endemic for Western Siberia, often associated with iron deficiency anemia, their high frequency in the anamnesis of pregnant women is noted. Establishing a correlation between subclinical hypothyroidism, hormonal correction and pregnancy complications requires further research. An obstacle is the lack of proper diagnosis of the TSH level in women who give birth on an emergency basis in early gestational periods.

Keywords

• pregnancy
• thyroid gland
• subclinical hypothyroidism
• preterm birth
• thyroid-stimulating hormone