Pre-pregnancy weight and weight gain during pregnancy are important determinants in the endocrine modulation of fetal growth restriction

Abstract

Objective: Pre-pregnancy weight, nutritional status, and the amount of weight gained during pregnancy, are extremely useful indicators of fetal growth and outcome. Suboptimal maternal nutrition could have a direct effect on the organs of the developing fetus and/or affect the endocrine milieu in the maternal feto-placental unit resulting in "fetal growth restriction" which may be a significant risk factor for adult onset disease. We investigated endocrine adaptation by the fetus to overcome the growth disadvantage caused due to poor weight gain in pregnancy as a result of maternal nutritional restriction. Materials & methods: We examined the quantitative variations in hormonal profiles in paired maternal and cord blood samples obtained from mothers and their neonates who were classified based on maternal weight gain during the entire pregnancy. Results: 1) A total of 37.4 % mothers gained less than 6 kg during the entire pregnancy. 2) Anthropometric parameters measured in the mothers indicate that these mothers were nutritionally restricted both prior to and during pregnancy. 3) We observed increased levels of growth hormone, placental lactogen, prolactin and thyroxine (T4) and decreased levels of insulin in the cord blood of neonates and decreased insulin and TSH levels in maternal blood in the study group (< 6kg weight gain during pregnancy) as compared to the control group (> 6kg weight gain during pregnancy). Conclusion: Our results suggest that insufficient weight gain in pregnancy due to suboptimal maternal nutritional status results in fetal adaptation to a growth restricted environment by modulation of the pituitary-thyroid axis thereby altering the endocrine milieu resulting in significant "fetal growth restriction".