The BMI is widely accepted as a simple and fairly accurate way to assess body weight in relation to health for most people between 20 and 65 years of age. A woman's BMI prior to pregnancy is used to establish an appropriate weight-gain range during pregnancy. Appendix 6 of the main guidelines document describes how to take accurate height and weight measurements. Help women view their weight realistically. A healthy weight is not one weight but a range of weights that is consistent with good health.
Healthy weights differ among people of the same height because body builds and shapes vary.
Before conception, discuss the implications of pregnancy for women with existing medical conditions such as renal, cardiovascular, endocrine, gastrointestinal, immunological, or nervous disorders and help them initiate a plan to be as healthy as possible before they become pregnant. Address other factors that may have an impact on the health of women and children such as smoking, alcohol and drug use, poverty, and violence. In the developed world, maternal smoking is the principal cause of low birth weight. Pregnant women are particularly receptive to advice regarding their health and the health of their family. Advice provided during pregnancy should be tailored to their specific needs and circumstances.