Association of maternal thyroid dysfunction and autoimmunity with adverse birth outcomes

Abstract

We aimed to explore the relationship between thyroid function and autoimmunity and adverse birth outcomes. Serum levels of thyroid function were detected by electrochemiluminescence assay. Urine iodine concentration was detected using the acid digestion method. We used multiple linear regression to assess the correlation between thyroid function indicators and birth weight according to trimester stratification, and binary logistic regression to evaluate the correlation between thyroid dysfunction and adverse birth outcomes. Reference ranges for trimester-specific thyroid hormones were established in our 2564 pregnant women cohort with mild iodine deficiency. The higher maternal TSH in the first trimester (β 0.09, p = 0.048) and total triiodothyronine (TT3) in the third trimester (β 0.16, p < 0.001) of TPOAb negative women, the higher birth weight Z-score. Whereas the second trimester free thyroxine (FT4) of mothers with TPOAb negative was lower (β -0.10, p = 0.026), the birth weight Z-score was higher. Pregnant women with overt and subclinical hyperthyroidism had a higher risk of preterm births than euthyroid women (11.9% vs. 4.5%; odds ratio [OR]: 2.84; p = 0.009). Women with higher TT3 had a higher risk of preterm (17.0% vs. 4.5%; OR: 4.19; p < 0.001) and LGA (34.0% vs. 11.1%; OR: 3.70; p < 0.001) births than euthyroid women. In conclusion, thyroid function during pregnancy could affect birth weight and birth outcome.

Assessment of Small for gestational age as a health risk for thyroid impairment in preterm infants

“…Pregnant women with hyperthyroidism were more likely to experience fetal development limitation (22). He et al [23] proposed that the key phase for maternal TSH and maternal FT4 is the first trimester for maternal TSH and the second trimester for maternal FT4. One possible explanation is that hyperthyroidism causes increased protein and lipid breakdown, resulting in prolonged caloric deficit and birth weight decrease [24].…”

The Thyroid Hormone Axis and Female Reproduction

“…In most cases, HG requires supportive management but rarely warrants pregnancy termination. Overt hyperthyroidism represents the most pressing concern for clinicians due to the increased odds of adverse events such as ICU admission, venous thromboembolism, and preterm premature rupture of membranes [ 141 , 142 , 212 ]. In contrast, milder and benign forms of hCG-mediated hyperthyroidism may be clinically subtle, presenting with subclinical hyperthyroidism characterized by suppressed TSH and an elevation in T3 and/or T4 <1.5 times the upper limit of normal.…”

Can Pathological Conditions of the Thyroid Gland During Pregnancy Affect the Course and Outcome of Pregnancy and The Parameters of the Newborn?

“…Maternal thyroid dysfunction during pregnancy can affect the newborn's risk of infection indirectly by impacting their overall health and immune system. As we have already mentioned, untreated pathological thyroid conditions during pregnancy are associated with premature birth and low birth weight, and both factors increase the risk of perinatal infection (15). All these complications can have long-term effects on the health and development of the child.…”