MATERNAL OBESITY, АGE AND MATERNAL THYROID STATUS - AN INTRIGUING CONNECTION TO THE NEONATAL OUTCOME

Abstract

Introduction. Thyroid dysfunction is the second most common endocrine disorder affecting women of reproductive age. Higher body mass index (BMI>30 kg/m2) is linked with many endocrine abnormalities, including thyroid dysfunction. Gestational age at birth (GAB) and birth weight (BW) are important predictors of neonatal mortality and morbidity. The objective of this prospective study was to determine the adverse neonatal outcomes of women [small for gestational age (SGA), intrauterine growth restriction (IUGR) and others] complicated with impaired thyroid function and obesity, when compared with those with normal function. Methods. Dried blood spot and urine samples were analyzed for thyroid and iodine status in 358 pregnant women in any gestational week, without known thyroid disorders. They gave birth at the University Clinic of Gynecology and Obstetrics-Skopje. The blood samples were analyzed with time-resolved fluoroimmunoassay in Zurich, and UIC was analyzed by mass spectrometry in Helsinki. Results. We found a significant positive correlation between total thyroxine (TT4) and GAB (p=0.045) and UIE and mother age (p=0.007), but a significant negative correlation between GAB and UIE (p=0.051), GAB and mother’s age (p=0.01), GAB and BMI (p=0.02). There was an inverse correlation between BW and maternal age (βst=-0.0641, P=0.010) and between BW and maternal TT4 (βst=-3.3640, P=0.0016). We found a positive correlation between BW and maternal BMI (βst = 21.847, P = 0.006). Conclusion. Overweight, obese and older women are at increased risk of thyroid dysfunction during pregnancy considered as high-risk pregnancies for adverse neonatal outcomes. We can use maternal TT4, BMI and age for predicting the BW.