A centile chart for weight gain in pregnancy for the urban population of the Western Cape, South Africa.

Weight gain during pregnancy was studied. Women with low body mass index (BMI) gained significantly more weight than women with high BMI. Older women gained significantly less weight than younger women. Centile charts were constructed using a maximum likelihood procedure. The centile charts for patients who are less than or equal to 25 years or with a BMI = less than or equal to 24 kg/m2 cannot be regarded as differing significantly, however the chart for patients greater than 25 years with a BMI greater than 24 kg/m2 does lie significantly below the others. For practical purposes the process of weight gain can be regarded as independent of gestational age. These charts can thus be used without knowledge of gestational age.