Reasons for the increasing incidence of macrosomia in Harbin, China.

A population-based retrospective study was conducted in Harbin,China. The medical records of 13 711 singleton infants born between 2001 and 2005 in 16 hospitals were reviewed. The incidence of macrosomia (birthweight ≥4000 g) was found to have increased from 8.31% in 2001 to 10.50% in 2005. Over this period, the ponderal index decreased and birth length increased in infants with macrosomia. In a multivariate analysis, risk factors for delivery of a newborn with macrosomia were found to be high prepartal body mass index (BMI), maternal height ≥165 cm, male gender of the newborn, gestational age of 40-41.9 weeks, maternal age ≥30 years and a maternal diagnosis of hypertension. The increase in the incidence of macrosomia in Harbin was attributable to increases in maternal prepartal BMI, height and age in the population.