Exploring the relationship between maternal body mass index and offspring birth weight: Analysis of routinely collected data from 1967 to 2010 in Aberdeen, Scotland

Abstract

A retrospective cohort study was undertaken to assess the relationship between maternal body mass index (BMI) and neonatal birth weight. Data were extracted from Aberdeen Maternity and Neonatal Databank on all deliveries (n = 94049) occurring between 1967 and 2010. Compared with mothers whose weight was in the normal range, the adjusted odds of delivering a high-birth-weight infant were 0.63 (95% confidence interval: 0.59, 0.67), 1.44 (1.39, 1.50); 1.83 (1.72, 1.95); 2.22 (2.04, 2.43) in underweight, overweight, obese and morbidly obese mothers, respectively. Similarly, the adjusted odds of delivering a low-birth-weight baby decreased with increasing maternal BMI from 1.38 (1.23, 1.55) in underweight women to 0.80 (0.72, 0.89) in overweight women; 0.78 (0.67, 0.93) in obese and 0.56 (0.44, 0.71) in morbidly obese mothers. These relationships were only evident after adjustment for gestational age, presumably because higher maternal BMI is also, in some cases, associated with pre-term deliveries.

Keywords::

• Birth weight
• maternal body mass index
• obese
• overweight
• underweight

Acknowledgements

The authors would like to thank Ms Katie Wilde, Data Management Team, University of Aberdeen for extracting data from the AMND. Viktor Hardock performed this analysis as a visiting student at the University of Aberdeen from the University of Bremen as part of the Erasmus internship scheme.

Funding source

The project did not receive any external funding. Viktor Hardock was supported by an Erasmus fellowship.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.