Fetal weight gain at term: linear with minimal dependence on maternal obesity.
OBJECTIVE
Our purpose was to determine the shape of the function relating birth weight to gestational age between 37.0 and 42.0 weeks of pregnancy and to determine the effect of maternal obesity on term fetal weight gain in normal pregnancies.


METHODS
Birth weights in 326 singleton, term gestations were studied in nondiabetic, nonsmoking white women who had well-dated, uncomplicated pregnancies.


RESULTS
Birth weight was a linear function of gestational age between 37.0 and 42.0 weeks. Mean (+/- SD) fetal weight gain was 12.7 +/- 1.4 gm per day (95% confidence interval 9.9 to 15.5 gm/day). Fetal weight gain was only 0.6 gm per day greater for obese pregnant women than for those of normal weight for height. Male fetuses gained weight 0.5 gm per day faster than females.


CONCLUSIONS
Fetal weight gain is a linear function of gestational age between 37.0 and 42.0 weeks of pregnancy for normal gestations. The effect of maternal obesity on fetal weight gain at term is small and not clinically significant.
Nahum
G G
GG
Department of Obstetrics and Gynecology, Good Samaritan Hospital of Santa Clara Valley, San Jose, California, USA.
Stanislaw
H
H
Huffaker
B J
BJ
D000328:Adult; D001724:Birth Weight; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009765:Obesity / Q000150:complications*; D011247:Pregnancy; D011248:Pregnancy Complications; D012044:Regression Analysis; D012737:Sex Factors; D015430:Weight Gain