Association between Maternal Thyroid Hormone Level and Fetal Weight

Aims: Present study is aimed to find out the association between maternal thyroid hormone at delivery and weight of delivered fetus.

Study Design: This is a case-control study in which low birth weight was cases and appropriate for gestational age were considered as control.

Place and Duration of Study: Study was conducted at National Institute of Pathology (ICMR), New Delhi and Department of Biotechnology, Invertis University, Bareilly from July 2018 to July 2020.

Subjects and Methods: A total of 193 maternal blood samples were collected and fetal parameters were recorded as per inclusion criteria. Quantitative estimation of Triiodothyronine (T3), Thyroxine (T4), and Thyroid Stimulating Hormone (TSH) was done in the separated serum samples by pre-coated ELISA kits and data analysis was performed using SigmaStat. Cases include women having full-term deliveries with birth weight < 2.5Kg i.e. Low Birth Weight (LBW) and Controls includes women having Appropriate for Gestational Age (AGA) delivery with birth weight > 2.5Kg.

Results: No significant difference was observed in maternal age as well as age at marriage and other demographic parameters, while maternal weight and BMI is significantly less in LBW as compared to AGA i.e. 49.62±5.34 & 53.96±6.92 and 21.32±4.01 and 22.66±1.57 respectively having P<0.001. Pearson correlation coefficient also revealed a significant negative correlation of T4 with both fetal weight and fetal length and a positive correlation of T3 with fetal weight, fetal length, and fetal head circumference, whereas TSH did not show any significant association with fetal parameters.

Conclusion: It was concluded that maternal T3 and T4 affects the fetal development during gestational period, TSH did not show any significant association with fetal parameters.