Effects of Maternal Hypothyroidism on Preterm Labor and Neonatal Outcomes: A Prospective Case-control Study

Hypothyroidism in mothers can lead to premature labor and problems in the newborn. However, the impact on neonatal outcomes, including respiratory distress syndrome (RDS) and hospitalization, is unclear.

To investigate the association between maternal hypothyroidism and preterm labor and its impact on neonatal outcomes, particularly RDS and neonatal health, in a group of pregnant women with spontaneous preterm labor.

This prospective case-control study at King George's Medical College, Lucknow, studied 509 pregnant women with spontaneous preterm labor between 28 and 37 weeks for 1 year and 6 months. The study included 69 hypothyroid women and 431 euthyroid women as a control group. Maternal thyroid function was measured by measuring thyroid-stimulating hormone (TSH), T3, T4, and anti-thyroid peroxidase (anti-TPO) antibodies. Neonatal outcomes included birth weight, gestational age, RDS, and cord blood TSH. SPSS 25.0 was used for t -tests, Chi-square tests, correlation analyses, and logistic regression.

Preterm labor was more likely in hypothyroid mothers than in euthyroid mothers. The newborns of hypothyroid mothers, especially those with subclinical hypothyroidism, were more likely to have RDS, require treatment in the neonatal intensive care unit (NICU), and need advanced ventilatory support. Babies born to hypothyroid mothers had a higher TSH level in the umbilical cord blood. Thyroid dysfunction in mothers was associated with longer hospital stays in the NICU and a higher need for oxygen treatment in babies.

Preterm labor and poor neonatal outcomes are associated with maternal hypothyroidism, especially with subclinical levels. Recognizing and treating maternal thyroid dysfunction during pregnancy may improve neonatal health and reduce RDS and intensive care unit stays.