The Effect of Maternal Hypothyroidism on Fetal Umbilical Cord Brain-Derived Neurotrophic Factor Levels

Objective: Brain derived neurotrophic factor (BDNF) is the most important neurotrophin, which helps the differentiation and growth of central and peripheral neurons, and facilitates synaptic transmission. In this study we aimed to investigate fetal cord BDNF levels of infants born from subclinical and clinical maternal hypothyroidism. Methods: This study was conducted on a total of 67 pregnant women who were followed up in Obstetrics and Gynecology outpatient clinics, 27 with maternal hypothyroidism and 40 age-parity matched healthy pregnants without hypothyroidism. Immediately after vaginal or cesarean delivery fetal cord blood samples were taken from these patients and BDNF levels were measured. Results: BDNF levels of infants born from pregnants with maternal hypothyroidism were significantly lower than the control group (23.3 ± 17.4 ng/dl and 50.7 ± 28.3 ng/dl respectively; p<0.001). In multiple linear regression analysis, while BDNF level was related with maternal hypothyroidism and infant sex, it was not associated with mode of delivery, maternal age, total weight gain during pregnancy, gestational age at birth, thyroid stimulating hormone (TSH) levels and other neonatal data. Conclusion: This study showed that fetal cord BDNF levels significantly decreased in infants of the pregnants with hypothyroidism. Key words: Pregnancy, maternal hypothyroidism, brain derived neurotrophic factor, levothyroxine