June 2018 | Meitheamh 2018

Birth Weight & Gestational Weight Gain

Mon, 18 June 18 15:33

 Is birth weight the major confounding factor in the study of gestational weight gain?: an observational cohort study

There has been much interest on both maternal obesity and gestational weight gain (GWG), particularly on their role in influencing birth weight (BW). Several large reviews have reported that excessive GWG’s associated with an increase in BW. However recent large, well-designed, randomized controlled trials studying interventions aimed at reducing GWG have all consistently failed to show a reduction in BW despite achieving a reduction in GWG.

Researchers at the UCD Centre for Human Reproduction at the Coombe Women and Infants University Hospital have published the results of an observational cohort study of the topic.  The aim of the longitudinal prospective study was to examine the relationship between GWG and birth weight in women where GWG and Body Mass Index (BMI) were measured accurately in a strictly standardised way.

A total of 522 women were enrolled at their convenience before 18 week gestation with height and weight accurately measured at the first antenatal visit. Maternal weight was measured again after 37 weeks gestation and the weight of the baby was measured at birth.  Body Mass Index was calculated and the relationship between GWG and BW was analysed. 

The group concluded that the positive correlation between GWG in pregnancy and BW can be accounted for by the contribution of fetal weight to GWG antenatally without a contribution from increased maternal adiposity. There was a wide range of BW irrespective of the degree of GWG and obese women had a lower GWG than non-obese women. These findings help explain why Randomized Controlled Trials (RCTs) designed to reduce GWG have failed to decrease BW and suggest there is no causative link between excessive GWG and increased BW.

Original Article

Is birth weight the major confounding factor in the study of gestational weight gain?: an observational cohort study

Amy C. O’Higgins, Anne Doolan, Thomas McCartan, Laura Mullaney, Clare O’Connor and Michael J. Turner  BMC Pregnancy and Childbirth (2018) 18:218 https://doi.org/10.1186/s12884-018-1843-9 [link]