What are the Gestational Weight Gain Guidelines?
Thanks to extensive research, involving thousands of pregnant women of different weights and sizes, the GWG guidelines were developed to optimise health outcomes for a mother and her child based on the mother's pre-pregnancy BMI.
The Institute of Medicine published GWG guidelines in 1990 and these guidelines were re-examined and updated in 2009 (IOM, 2009). In the updated guidelines, obese women are encouraged to aim for lower weight gain than recommended in the earlier guidelines. According to the most recent IOM guidelines, obese women are recommended to gain 5 to 9kg, which is less than overweight women (7-11.5kg) and in turn less than the recommendations for healthy weight women (11.5 to 16kg)
The GWG guidelines are based on your patient's pre-pregnancy BMI and take into account:
- The weight of the baby and supporting structures i.e., placenta and uterus; these weigh a similar amount for all women regardless of their pre-pregnancy BMI.
- The changes in body composition to support pregnancy; these vary depending on body composition before becoming pregnant.
- Differences in pregnancy weight recommendations relate to the amount of extra weight needed to accommodate breastfeeding. Women with a normal pre-pregnancy BMI (18.5-24.9 kg/m2) will probably need to gain more weight to support the energy burden of breastfeeding than women with a high BMI (greater than 30 kg/m2).
Staying within these pregnancy weight gain recommendations will not only reduce the risk of complications for your patient and their baby during pregnancy and the birth but also help to improve weight status post-birth.
Source: Institute of Medicine (IOM) and National Research Council (NRC) *For single pregnancies only (i.e. not twins, triplets)