A new study finds that many women are in the dark as to how much weight they should gain during pregnancy.

Two-thirds of Australian mothers-to-be weren’t clear on appropriate weight gains while pregnant, with as much as a third of women gaining too much weight, according to a study published in the Australian and New Zealand Journal of Obstetrics and Gynaecology. The study involved more than 660 pregnant women.

How much pregnancy weight should you gain?

The study, announced Friday, also showed that more than half of the women who were overweight before becoming pregnant gained too much maternity weight, compared to only a third of their leaner counterparts.

“The majority of the women in the study knew healthy eating was important, but very few could identify how much they should be eating from different food groups, particularly fruits and vegetables,” says study author Susie de Jersey of Queensland University of Technology’s Institute of Health and Biomedical Innovation and senior dietician at the Royal Brisbane and Women’s Hospital.

In addition, less than half of the study’s participants rated exercise during pregnancy as important.

“There are a lot of psychosocial factors in play — many of these women may have more negative experiences from trying to control their weight in the past,” she says. “The reality is that some women find it easier to control their weight than others both before and during pregnancy.

The research team offers the following guidelines:
If your pre-pregnancy BMI was: Less than 18.5 kg/m² you should gain: 12.5 to 18 kg
If your pre-pregnancy BMI was: 18.5 to 24.9 kg/m² you should gain: 11.5 to 16 kg
If your pre-pregnancy BMI was: 25 to 29.9 kg/m² you should gain: 7 to 11.5 kg
If your pre-pregnancy BMI was: Above 30 kg/m² you should gain: 5 to 9 kg

Access the study: http://onlinelibrary.wiley.com/doi/10.1111/ajo.12013/abstract