Relationship between maternal bone biomarkers and fetal adiposity through normal pregnancy

Purpose To examine the association of maternal bone markers (sclerostin, sRANKL, osteocalcin, 25OHD3) with fetal intra-abdominal and subcutaneous adipose tissue deposition and birthweight during normal pregnancy. Methods One hundred pregnant women (aged 30.4±5.6 years, mean±SD) with pre-pregnancy BMI=24.1±4.6 kg/m² were seen prospectively during each trimester. At each visit they were submitted to anthropometric measurements, a fasting blood sampling, a 75gr oral glucose tolerance test (OGTT) and a fetal ultrasonogram. At birth, neonates had birth weight measurement. Results In the 2 nd trimester maternal sclerostin concentrations correlated positively with fetal abdominal circumference and birth weight; maternal sRANKL concentrations correlated positively with fetal abdominal subcutaneous fat thickness, sagittal abdominal diameter and abdominal circumference. Fetuses born to mothers with greater (>254 ng/mL) compared to fetuses born to mothers with lower (≤254 ng/mL) sRANKL concentrations had greater abdominal circumference, sagittal diameter and abdominal subcutaneous fat thickness. Maternal serum sclerostin concentrations were the best positive predictors of birth weight. In the 3 rd trimester maternal sclerostin concentrations correlated positively with fetal sagittal abdominal diameter; maternal sRANKL concentrations positively correlated with fetal abdominal circumference and fetal abdominal sagittal diameter. Conclusions Maternal bone markers sclerostin and sRANKL may relate with fetal intra-abdominal adipose tissue deposition through direct or indirect unknown as yet mechanisms contributing thus, to birthweight