The association between fetal growth and neonatal adiposity in urban South African infants.

OBJECTIVE

To examine associations between maternal body mass index (BMI), gestational weight gain (GWG) and fetal growth and neonatal adiposity in urban South Africans.

METHODS

Maternal BMI was assessed at recruitment and GWG (kg/week) was calculated. Longitudinal fetal growth was measured via ultrasound and modelled using Superimposition by Translation and Rotation (SITAR). Neonatal adiposity was assessed using air displacement plethysmography or dual-energy X-ray absorptiometry. Multiple linear regression models were used to examine associations between maternal BMI, GWG and SITAR fetal growth parameters and neonatal fat mass index (FMI; kg/m ) in 304 mother-neonate pairs.

RESULTS

In pooled analyses, longitudinally modelled abdominal circumference size (β = 0.64 kg/m , P < .001) and velocity (β = 8.39 kg/m , P < .001) and biparietal diameter velocity (β = 4.55 kg/m , P = .020) were positively associated with neonatal FMI. GWG was positively associated with neonatal FMI in preliminary models (β = 1.07 kg/m per 1 kg/week; P = .040), with pooled models indicating mediation via fetal growth.

CONCLUSION

In utero abdominal growth is predictive of neonatal adiposity. Additionally, greater fetal growth - particularly of the abdominal circumference - mediates the effect of GWG on neonatal adiposity. In settings such as South Africa, strategies to ensure healthy pregnancy weight gain can contribute to prevention of intergenerational obesity risk.