Most pregnant New Zealand women don't know whether they are putting on a healthy amount of weight or not, an Otago University study has found.
It also says women who are overweight or obese are the most likely to lack accurate knowledge of their body size.
Researchers asked 641 Dunedin and Christchurch women who were having their 12-week scans which BMI category (underweight, normal weight, overweight, and obese) they believed they fell into and what the corresponding recommended weight gain during pregnancy was.
Only 31 percent could identify the appropriate weight gain for their category.
As well as facing risks such as high blood pressure and gestational diabetes, pregnant women who gain excess weight are more likely to have overweight and obese children, says study co-author Dr Helen Paterson.
"This study indicates that more education needs to be provided and emphasis given to weighing and measuring women, and also accurately advising them of their specific gestational weight gain targets," she says.
"Without this we are not fulfilling our responsibilities as healthcare professionals and essentially expecting women to fly blind."
The findings are published in this week's edition of the New Zealand Medical Journal.