Weight and weight gain in pregnancy used to be an obstetric obsession, if not an oppression. Belief that weight restriction could prevent pre-eclampsia made scales the most feared instruments in antenatal clinics,1 causing some women to resort to fasting before their next appointment. Nearly 20 years ago, the routine use of scales started to diminish, in the same way as it had begun — without good evidence.1 Attention shifted to the weight of the offspring, and achieving birthweights within the 3000–4000 g bracket, which are associated with better perinatal outcomes.2 Evaluations of the resulting guidelines for weight gain in pregnancy2 (recently revised)3 also centred on birthweight, with less attention to more substantive perinatal and infant outcomes.4 The evaluations also showed that only a minority of women achieve an ideal weight gain;4 many gain more than is recommended, and excessive gain is most frequent in those who are overweight already.4

©The Medical Journal of Australia 2009 www.mja.com.au PRINT ISSN: 0025-729X ONLINE ISSN: 1326-5377