Effect of fat and fat-free mass deposition during pregnancy on birth weight.
OBJECTIVE
The purposes of our study were to describe the patterns and location of fat and fat-free mass deposition during pregnancy and to evaluate their effects on fetal growth.


METHODS
Our study is a prospective follow-up of 105 healthy pregnant women who were delivered of term infants. Body composition was evaluated eight times during gestation with anthropometric measures and bioimpedance techniques. Body fat and fat-free mass were calculated with equations specifically developed for this population.


RESULTS
Total weight gain was 10.0 +/- 3.5 kg; net weight gain was 3.7 +/- 0.31 kg; birth weight was 3211 +/- 467 gm (values are mean +/- SEM). In these women fat was deposited mostly in the thigh and subscapular region for a total of 6.23 +/- 0.19 kg at term. The period of pregnancy of the largest maternal fat deposition per week is between the twentieth and thirtieth weeks. After adjusting by prepregnancy weight, birth weight is associated with maternal changes in thigh skin folds and fat gain before the thirtieth week of gestation. Infants born to mothers with low fat gain before the thirtieth week were 204 gm lighter than infants born to mothers with fat gain > or = 25th percentile of this population.


CONCLUSIONS
Maternal nutritional status at the beginning of gestation and the rate of fat gain early in pregnancy are the two nutritional indicators most strongly associated with fetal growth in this population.
Villar
J
J
Division of Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Baltimore, Maryland.
Cogswell
M
M
Kestler
E
E
Castillo
P
P
Menendez
R
R
Repke
J T
JT
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D001724:Birth Weight; D001823:Body Composition; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D011247:Pregnancy / Q000378:metabolism*; D011446:Prospective Studies; D012885:Skinfold Thickness; D015430:Weight Gain