Macrosomia and low birth weight (LBW) can be associated with pregnancy complications and may affect the long term health of the child. The aim of this study was to evaluate the metabolomic serum profiles of healthy pregnant women to identify early biomarkers of macrosomia and LBW, and to understand mechanisms leading to abnormal fetal growth not related to mother's body mass index (BMI) or presence of gestational diabetes (GDM).

Serum samples from 770 women were collected between the 12^th-14^th gestational week. After delivery samples were divided into three groups according to the infant birth weight: low <2500 grams; normal 2500-4000 grams; and high >4000 grams. Samples from women with any complications of pregnancy were excluded. Serum fingerprinting was performed by LC-QTOF-MS.

Lower levels of phospholipids, lysophospholipids and monoacylglycerols; low vitamin D3 metabolites, and increased bilirubin level were associated to macrosomia. Because most changes involved lipids, as a concept of validation, adipocyte fatty acid binding protein (A-FABP) levels were measured and found correlated with the studied lipids and birth weight.

Serum fingerprinting in early pregnancy can predict the risk of macrosomia. Serum levels of A-FABP and several lipids are promising prognostic markers for macrosomia in healthy pregnancies. This article is protected by copyright. All rights reserved.