[Nutritional characteristics of newborns of overweight and obese mothers]

Introduction: Maternal nutritional status is an important factor of adequate intrauterine growth and neonatal weight. The aim of this study is to evaluate the relationship between pre-gestational BMI (Body Mass Index) and breastfeeding duration, as well as infant anthropometric measurements during their first six months of life.

Materials and methods: Anthropometric measurements and the type of feeding were evaluated in a representative sample of 1,547 newborns from our population during 2009, according to their maternal BMI, and also in a sub-cohort of 759 infants followed up to 6 months of life.

Results: A total of 72.9% of women had a normal weight, 18.7% were overweight and 8.4% obese. Women with a BMI ≥ 25 kg/m(2) had lower weight gain during pregnancy (P < .001), lower socioeconomic and cultural level (P < .001), and their infants had higher weight at delivery (P=.003) and at 6 months of life, with no differences in body length. Newborn weight increased in relation to maternal BMI, but over 35 kg/m(2) it decreased progressively (P < .001). Breastfeeding prevalence in obese women was 58.5% at hospital postpartum discharge, and 8.6% at six months of life; as opposed to 70.8% and 13.9%, respectively in women with normal BMI.

Conclusions: In our sample, maternal obesity is associated with a low socioeconomic and cultural level, higher infant weight at delivery and at 6 months of life, and less prevalence of exclusive breastfeeding; all of them nutritional risk factors in the short and long term.