Fetal macrosomia in a Hispanic/Latinx predominant cohort and altered expressions of genes related to placental lipid transport and metabolism.

INTRODUCTION

Fetal overgrowth, termed fetal macrosomia when birth weight is >4000 g, is the major concern in the treatment of gestational diabetes mellitus (GDM). However, to date, the underlying mechanisms of fetal macrosomia have not been understood completely. Placental lipid metabolism is emerging as a critical player in fetal growth. In this study, we hypothesized that fatty-acid transport and metabolism in the placental tissue is impaired in GDM women, dependent on fetal sex.

METHODS

To test this hypothesis, we analyzed the incidence of GDM, fetal macrosomia, and obesity in a large cohort consisting of 17,995 pregnant subjects and majority of subjects being Hispanic/Latinx, and investigated expression of genes related to lipid transport and metabolism in placentas from obese women with or without GDM, and with or without fetal macrosomia.

RESULTS

The main findings include: (1) there was a higher incidence of GDM and obesity in Hispanic subjects compared with non-Hispanic subjects, but not fetal macrosomia; (2) expressions of most of genes related to placental lipid transport and metabolism were not altered by the presence of GDM, fetal macrosomia, or fetal sex; (3) expression of FABP4 was increased in obese women with GDM and fetal macrosomia, and this occurred in male placentas; (4) expression of LPL was decreased in obese women with GDM despite fetal macrosomia, and this occurred in male placentas; (5) expression of ANGPTL3 was decreased in obese women with GDM and fetal macrosomia, but was not altered when fetal sex was included in the analysis.

CONCLUSIONS

This study indicates that there is race disparity in GDM with higher incidence of GDM in obese Hispanic women, although fetal macrosomia disparity is not present. Moreover, altered placental lipid transport may contribute to fetal overgrowth in obese women with GDM.