Twin pregnancy: the distribution of maternal weight gain of non-smoking normal weight women.

We documented the pattern and distribution of weight gain through twin pregnancies of healthy non-smoking women with good birth outcomes. The mean birthweight was 2621 g and the mean gestational age at delivery was 37.6 weeks. As few of the women were weighed after 34 weeks, the weight gain graph was drawn to this point. The sample was separated into subgroups based on birthweights and gender of the infants. Weight gains, parity, income, first measured weight, BMI and Apgars were not different between the subgroups. The only difference between those with infants that were small for gestational age (SGA), over 3 kg, or intermediate in weight was gestational age. For the groups divided by infant gender, the only differences were maternal age and infant birthweight. The mean, median and 80% confidence limits for weight gain at 34 weeks were 14.1, 13.6, and between 8.5 and 19.4 kg, respectively. There was a wide range of weight gained by these women carrying twin pregnancies.