Expectant mothers often worry about their weight during pregnancy. Are they gaining too much? Putting on too little? New research published in the Australian and New Zealand Journal of Obstetrics and Gynaecology found that two out of three Australian moms-to-be didn’t know how much weight gain was appropriate during pregnancy. About one quarter gained too little weight, and over one third gained too much.

So what’s the goal for pregnancy weight gain? “Ideal weight gain is dependent on your pre-pregnancy BMI (body mass index, a formula based on your height and weight),” says Dr. Heather Taylor, a family doctor in Calgary who practises low-risk obstetrics. “A normal BMI is 18.5 to 25. If we assume the average pregnant person is in the healthy weight range, we’re looking for 25 to 35 pounds of weight gain in the whole pregnancy.” When an expectant mom is overweight – officially a BMI of 25 to 30 – overall weight gain for the pregnancy should be 15 to 25 pounds, says Dr. Taylor.

Moms-to-be often wonder what and how much they should eat. Fabijana Jakulj, a registered dietitian in Calgary says that the old adage that you are “eating for two” is incorrect; rather, pregnant women should “eat twice as healthy, not twice as much.” The first trimester shouldn’t see that much weight gain, says Fabijana. “Before pregnancy, and in the first trimester, we want to focus on maximizing the nutrients in the food rather than adding a lot of extra calories.” In the second and third trimesters, gaining one pound per week is ideal. This amount of weight gain requires an extra 350 and 450 calories in the second and third trimesters respectively, says Fabijana.

In some cases, a woman doesn’t gain the recommended amount of weight during pregnancy. In these circumstances, visiting the doctor more frequently for monitoring is important. “These women will often get a few extra ultrasounds, just to check to make sure the baby is still growing well,” says Dr. Taylor. But as long as the pregnant woman is eating healthy and getting regular checkups, it could just be a case of a strong metabolism.

Exercise and Dieting During Pregnancy

  • Get regular exercise during pregnancy. Family doctor Heather Taylor says, “We absolutely encourage pregnant women to remain active. If you already have an exercise program, at least for the first half of the pregnancy, you can keep it up.” Just listen to your body to make sure you feel good.
  • If you haven’t been active before, start with something as simple as walking. As women get larger (and the centre of gravity changes) switch over to lower impact activities, like swimming, says Dr. Taylor.
  • Ditch the calorie restrictive diet. “Even if a woman is overweight, we would not recommend trying to lose weight during a pregnancy,” says registered dietician Fabijana Jakulj. “Eating as well as possible and getting your nutrients is the primary goal. Weight loss is something to focus on after the baby is born.”

Pick up a copy of Expecting magazine at your doctor’s office, or read more at ParentsCanada.com/pregnancy

Originally published in ParentsCanada magazine, November 2013.