A lifestyle intervention can help women control their weight gain during and after pregnancy, according to a new study.
It will also help normal-weight, obese and overweight women return to pre-pregnancy weight after delivery.
"This study suggests that a lifestyle intervention can help women manage their weight during pregnancy, prevent health problems during pregnancy, and reduce weight retention after having a baby," said lead author Suzanne Phelan at the Brown University and The Miriam Hospital.
The researchers, who conducted a randomised controlled study of 400 women, found that women whose weight was in a normal range before pregnancy were more likely to stay at a healthy weight if they received the intervention during pregnancy compared to women who received standard care.
The intervention also increased the chance of returning to their pre-pregnancy weight six months after delivery.
However, it did not help women who were obese or overweight before becoming pregnant to stay within the recommended weight gain goals during pregnancy, but it did help them return to their pre-pregnancy weight after delivery.
The team devised an intervention that they hoped would be effective, but also 'low-intensity' so that clinicians and patients could stick with it.
Patients randomly selected to receive the intervention went to an initial, face-to-face meeting with an interventionist and received scales, pedometers and forms for recording what they ate.
The intervention proceeded exclusively via the mail and by phone with weekly reminder postcards and three calls from a dietician to offer encouragement.
After each visit to their doctor's office, the women would also receive graphs showing them their weight gain compared to what would be ideal based on health guidelines.
Women who were gaining too much or too little received additional follow-up coaching calls from the study dietician.
Among normal-weight women who received the intervention, 40.2 percent gained more than the Institute of Medicine's recommendations, but among comparable women who did not receive the intervention, 52.1 percent gained too much.
Six months after delivery, 35.6 percent of women who received the intervention were at or below their pre-pregnancy weight, compared to only 20.7 percent who received only standard care.
Obese or overweight women struggled more to control their weight during pregnancy.
Exactly 66.7 percent of obese or overweight women who received the intervention and 61.1 percent of those who did not gained more than the 1990 IOM recommendation.
After birth, obese or overweight women did gain a statistically significant benefit from the intervention - 25.6 percent of those in the intervention group returned to their pre-pregnancy weight or below, compared to only 16.7 percent of women who received standard care.
Normal-weight women in the intervention group were nearly four times less likely to experience high blood pressure and three times less likely to have preeclampsia.
The study is published online in the American Journal of Clinical Nutrition.