Geburtshilfe Frauenheilkd 2011; 71 - A3
DOI: 10.1055/s-0031-1292694

The combined influence of maternal body mass index (BMI) and smoking on the somatic development of female and male neonates

J Weller 1, M Voigt 2, E Schleußner 1, V Briese 3, D Olbertz 3, V Hesse 2
  • 1Jena University Hospital, Obstetrics and Gynecology, Jena, Germany
  • 2German Center for Growth, Development and Health Encouragement during Childhood and Youth, Berlin, Germany
  • 3Hospital Südstadt, Neonatology, Rostock, Germany

Background and aim:

Maternal BMI at the beginning of the pregnancy and smoking during pregnancy exert an influence on fetal growth. We aimed to quantify the combined influence of these factors for female and male neonates.

Material and methods:

Data of 508,926 singleton pregnancies from the German perinatal survey of 1998–2000 were available for analysis. Maternal daily cigarette consumption (when the pregnancy became known) was analysed in four groups (non-smokers, 1–7, 8–14, ≥15 cigarettes per day). Maternal BMI (from height and weight measurements obtained at the first obstetric consultation) was classified as underweight (<18.50kg/m2), normal weight (18.50–24.99), overweight (25.00–29.99), or obese (≥30.00). Neonates of non-smoking, normal weight mothers served as the reference population. For this reference population we calculated the 10th and 90th birth weight percentiles in order to classify neonates from all maternal BMI and smoking groups as small for gestational age (SGA), appropriate for gestational age (AGA), or large for gestational age (LGA). Data for female and male neonates are presented separately.

Results:

For underweight mothers smoking 15 or more cigarettes per day the SGA rate was 40.2% for female neonates and 36.7% for male neonates (reference population: 9.8%). For non-smoking obese women the LGA rate was 21.5% for female neonates (reference population: 9.8%); for obese heavy smokers the LGA rate for female neonates was 10.9%. For male neonates corresponding values were 20.8% and 12.2%.

Conclusions:

Smoking and BMI exert similar influences on the somatic classification of neonates of both sexes. Underweight heavy smokers experience very high SGA rates.