Gestational weight gain during pregnancy and its determinants: A longitudinal study

Gestational weight gain during pregnancy is supposedly associated with the increased risk of some adverse outcomes. Thus, assessing the trend of gestational weight gain and its associated risk factors for each population may reduce the related harms. We examined the trend of gestational weight gain and some of its associated risk factors in a sample of Iranian pregnant women.

From five health centers in Isfahan, 458 pregnant women were selected through a multi-stage sampling method. The gestational weight gain was measured nine times during pregnancy. The latent growth curve model was used to investigate the trend of gestational weight gain and a random effects model was used to identify the factors affecting gestational weight gain during pregnancy.

The mean weight at the baseline was 58.7 ± 0.1 kg. It increased by a mean of 301 ± 0.0 grams per week. The pre-pregnancy weight (p<0.001) and parity (p<0.001) had a significant indirect effect, and motherchr('39')s height (p=0.028) had a significant direct effect on gestational weight gain. Motherchr('39')s age showed no significant effect on weight gain during pregnancy.

More than 50% of our sample had an abnormal weight gain. Thus, according to the criteria proposed by the American Institute of Medicine (IOM), it is vital to promote the knowledge of women and health care providers and raise their awareness about the determinants of abnormal gestational weight gain and their consequences.