TORONTO - The subject of weight gain is often a fixation for mothers-to-be as they share stories about their pregnancies, and when they step on the scale at their frequent doctor visits.

Now, a new report on weight gain during pregnancy offers some insights into the gaining and shedding of pounds before and after a woman gives birth.

The Maternity Experiences Survey conducted in 2006 reveals that women giving birth for the first time were more likely than those who had previously given birth to gain more weight than recommended.

And relatively high percentages of women who were young, less educated or aboriginal gained more weight than recommended when they were pregnant, said the study released Wednesday by Statistics Canada.

When the survey was conducted, the recommended ranges for weight gain in pregnancy were adapted from 1990 Institute of Medicine recommendations.

The ranges were 27.5 to 40 pounds for women with a pre-pregnancy body mass index of less than 20; 25 to 35 pounds for someone with a pre-pregnancy BMI of 20 to 27; and up to about 25 pounds for someone with a pre-pregnancy BMI greater than 27.1.

Fifty-five per cent of overweight women gained more than recommended while they were pregnant compared to 41 per cent of those who were in the normal range and 26 per cent who were underweight, the study found.

Women who gained less weight than recommended were more likely to give birth to a baby weighing less than a normal weight full-term infant.

Five to nine months after the birth of the baby, it was found that women who gained more weight than recommended during their pregnancies retained more weight -- an average of about 10 pounds -- than women who were within the recommendations, at an average of 4.4 pounds.

The survey involved responses from 5,554 women, aged 15 and older at the time of their baby's birth in Canada. Most of the mothers were surveyed at five to nine months postpartum.