[The influence of social and health factors including pregnancy weight gain rate and pre-pregnancy body mass on low birth weight of the infant].

OBJECTIVES: to investigate the influence of social and health factors on low birth weight (LBW) among Polish women. LBW is defined as birth weight less than 2500 g. MATERIALS: 27,015 perinatal data gathered from 40 Polish hospitals taking part in the OBSQID international project.
METHODS: Descriptive statistics and multifactorial logistic regression. Dependent variable: LBW. INDEPENDENT VARIABLES: maternal age, place of residence, marital status, education, parity, smoking, diseases before and during pregnancy, obstetrical history, pregnancy weight gain rate, prepregnancy BMI.
RESULTS: 6.4% LBW in all neonates, 2.0% LBW in full term neonates were ascertained. Among vaginal deliveries, increased risk of LBW have: underweight (OR=2.2); small pregnancy weight gain rate (OR=2.2); unmarried (OR=1.9); multiparous (OR=1.5); elementary education (OR=2.7); professional education (OR=2.3), mother age less than 20 years (OR=1.5); smoking before pregnancy (OR=1.7). Among cesarean section deliveries increased odds have: small pregnancy weight gain rate (OR=2.9), residence in town (OR=2.0), elementary education (OR=4.4); professional education (OR=2.8). LBW odds ratio for small pregnancy weight gain rate jointly with prepregnancy low BMI due to other factors was considerably high (OR=7.1 for vaginal delivery, OR=2.6 for cesarean section).
CONCLUSIONS: prepregnancy low BMI together with small pregnancy weight gain rate is an important risk factor for LBW. Mother age (under 20 years of age) decreases the risk of LBW.