Body composition of women with newborns who are small for gestational age

The relationship between maternal and placental hemodynamic disorders and fetal growth is well known, but few studies have evaluated a link between maternal extracellular water (EW) and newborn birth weight.

To identify the characteristics of body composition (BC) of women with small for gestational age (SGA) newborns, and to determine the relationship between maternal EW and birth weight of the baby.

We studied maternal BC using multifrequency bioelectric impedance in the second and third trimesters of pregnancy. Newborns with weight below the 10th percentile were classified as SGA; those with weights between the 10th and 90th percentiles as appropriate for gestational age (AGA), and large for gestational age (LGA) were those with weights above the 90th percentile.

We studied 460 women and their BC varied depending on whether their newborns were SGA, AGA or LGA. EW was lower in the mothers of SGA (11 +/- 2 l) compared to AGA (12 +/- 3 l) newborns (p < 0.01). We identified a significant relationship (p < 0.01) between maternal EW in the second trimester and the weight of the newborn, beta = 43 (95% CI 27-58).

BC of women whose newborns are SGA differs significantly from that of women whose newborns are AGA, a result which suggests that the mothers of SGA infants may have a disordered hemodynamic state during the second trimester of pregnancy.