Insulin resistance, a link between maternal overweight and fetal macrosomia in nondiabetic pregnancies.
OBJECTIVE
During the last decades the number of large for gestational age infants delivered by nondiabetic mothers has increased. Our aim was to investigate to what extent fetal growth in nondiabetic pregnant women can be explained by rates of maternal energy substrate production and resting energy expenditure.


METHODS
Twenty nonsmoking pregnant women without impaired glucose tolerance and with a wide range of fetal weights (0.2-2.7 SDS) were investigated at 36 weeks of gestation. Maternal lipolysis, glucose production, resting energy expenditure, body composition and insulin resistance were assessed.


RESULTS
Median (range) glucose production rate was 805 (653-1,337) μmol/min and that of glycerol, reflecting lipolysis, was 214 (110-576) μmol/min. Multiple linear regression analysis showed that maternal fat mass explained 36% of the variation in insulin resistance, accounting for 62% of the variation in glucose production. Further, glucose production explained 31% of the variation in fetal weight. Resting energy expenditure explained 51% of the variation in estimated fetal weight.


CONCLUSIONS
Fetal weight is dependent on maternal glucose production, which is in turn determined by the degree of insulin resistance, induced in part by the maternal fat mass. The variation in maternal resting energy expenditure is closely related to fetal weight.
Ahlsson
Fredrik
F
Diderholm
Barbro
B
Jonsson
Björn
B
Nordén-Lindberg
Solvig
S
Olsson
Roger
R
Ewald
Uwe
U
Forslund
Anders
A
Stridsberg
Mats
M
Gustafsson
Jan
J
D050154:Adiposity; D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D015992:Body Mass Index; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology*; D020567:Fetal Weight; D005943:Gluconeogenesis; D006801:Humans; D007231:Infant, Newborn; D007333:Insulin Resistance; D008066:Lipolysis; D050177:Overweight / Q000503:physiopathology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal