Pre-pregnancy body mass index, gestational weight gain and adverse birth outcomes: some evidence from Italy.

Background: Overweight and obese women present an increased risk of poor maternal and child health outcomes. The aim of this paper is to analyze the joint effects of pre-pregnancy body mass index and inadequate gestational weight gain on birth weight and gestational age in an Italian sample of pregnant women.

Methods: Data were obtained from a sample of about 2,000 pregnant women at the University Teaching Hospital of Perugia University (Italy) in 2013. We used the revised classification proposed by Institute of Medicine to identify gestational weight gains considered as appropriate. Logistic regression models were used to estimate the adjusted odds-ratios of women belonging to any BMI class different from normal (used as the reference category) and of women who increased their weight by an amount smaller or greater than normal, controlling for a large set of observable confounders.

Results: Higher probability of low birth weight was associated with both obesity (OR = 1.9124, s.e. = 0.526) and less than normal weight gains (OR = 2.3614, s.e. = 0.388). The probability of fetal macrosomia was found to be positively associated with more than normal weight increases (OR = 2.6232, s.e. = 0.465). Pre-term deliveries were associated with less than normal gestational weight gains (OR 1.7338, s.e. = 0.320).

Conclusion: Overweight and obesity represent a big issue for public health. In particular, weight management during pregnancy and pre-pregnancy could determine negative health outcomes in newborns. In our study we found that inadequate weight variations during pregnancy, according to the Classification of the Institute of Medicine, negatively influence health conditions at birth. Stronger initiatives, especially in terms of midwifery, nurse training and informative policies should be adopted by policy makers.