Relationship of maternal birth weight on maternal and neonatal outcomes: a multicenter study in Beijing

Birth weight is an important indicator for childhood and adulthood diseases. Published studies lack information on the relative contribution of women's own birth weight to the course of her pregnancy, not only for maternal but especially to neonatal outcome. The aim of the study was to evaluate the relationship of maternal birth weight on maternal and perinatal complications during pregnancy.

Medical and obstetrical data were collected from 5479 women at 15 hospitals in Beijing, by a systemic cluster sampling survey conducted from 20 June 2013 to 30 November 2013. These women were categorized into five groups, according to their own birth weight: low birth weight (⩽2500 g, n=275), sub-optimal birth weight (2500 to 2999 g, n=1079), optimal birth weight (3000 to 3499 g, n=2590; 3500 to 3999 g, n=1085) and high birth weight (⩾4000 g, n=450). The occurrence of maternal and neonatal complications was recorded and compared among the groups. Statistical analysis was performed by SPSS 20.0 and values of P<0.05 were considered to be statistically significant.

Low maternal birth weight was associated with higher rates of gestational diabetes mellitus (χ²=21.268, P=0.006) and hypertensive disorders (χ²=10.844, P=0.028). The latter association was strongest in women with a pre-pregnancy body mass index above 25 kg m^-2. Low maternal birth weight was also associated with an apparently higher incidence of preterm labor (χ²=18.27, P=0.001) and hypertriglyceridemia (χ²=2.739, P=0.027) in pregnancy. An association between women with low birth weight and a significantly higher rate of small for gestational age infants (χ²=93.507, P<0.001) and low birth weight (χ²=36.256, P<0.001) was detected. High maternal birth weight was associated with an increased risk of pre-pregnancy overweight and obesity (P<0.001), as well as for large for gestational age infants (χ²=93.507, P<0.001) and macrosomia (χ²=72.594, P<0.001).

In our study, high or low maternal birth weight was strongly associated with maternal and perinatal adverse pregnancy outcomes. This suggests that by controlling the birth weight of female infants among the normal range, adverse outcomes may be decreased in the future and for the following generations.