How much weight gain is too much?
Tracking weight in pregnancy is key for both mother and baby
Q. How much weight should I gain during pregnancy and what does it mean to my baby’s future if I struggle to keep my weight under control when pregnant? I tend to gain weight easily during pregnancy.
A. How much weight a woman gains during pregnancy affects the health of both the patient and her baby. A mother who gains more weight than is recommended during pregnancy puts herself at risk for diabetes, high blood pressure (pre-eclampsia), going into premature labour, enduring longer labour and delivering via a caesarean section.
From the baby’s perspective, their birth weight may be higher and, later in life, they may be at risk for becoming overweight or obese. Babies born to mothers who gained too much weight during pregnancy are at risk for asthma, allergies, heart abnormalities and metabolic abnormalities (metabolic syndrome).
Approximately one-third of pregnant patients who were at a normal weight before pregnancy gain more weight than experts recommend. And close to one half of pregnant patients who were overweight before they got pregnant gain too much weight during pregnancy.
Every few years, experts review the latest research and recommend guidelines for ideal weight gain during pregnancy. Some clinicians use the 5-10-10 rule (gain five pounds in the first trimester, 10 pounds in the second and 10 pounds in the third). However, the Institute of Medicine (IOM) recommendations remain the gold standard, and have been adopted by Health Canada and various provinces in Canada. The latest report by the IOM makes a few key
points: The pre-pregnancy BMI is a key starting point (ideally a healthy BMI is 18.5 to 24.9)
Normal weight women should gain 25 to 35 pounds in total during their pregnancy (11.5 to 16 kg)
Overweight women (BMI 25 to 29.9) should gain 15 to 25 pounds (7 to 11.5 kg)
Obese women (BMI over 30) should gain a total of 11 to 20 pounds (5 to 9 kg)
The IOM recommends that during the second and third trimesters, normal weight women gain 1 pound per week (0.4 kg); overweight women 0.6 pounds per week (0.3 kg) and obese women 0.5 pounds per week (0.2 kg). Overall, a rate of weight gain during pregnancy of 7 pounds per month (3 kg) is considered excessive.
From the research
Dr. David Ludwig, a Bostonbased researcher and obesity expert in children has published data in The Lancet that convincingly makes the point that what happens to the fetus in the womb — specifically as it pertains to how much weight a mother gains during pregnancy — sets the stage for later in life.
This is independent of genetics, and its exact mechanism is unclear.
Ludwig commented that women tend to be especially motivated to live healthily during pregnancy because it is not just their health that is at stake but also the baby they are expecting to deliver. (For example, some women may stop smoking, avoid alcohol 100 per cent, reduce their coffee intake or try to get more rest — all based on instinctively wanting to give their offspring a healthy start in life.)
In addition to Ludwig’s work, research published in the European Journal of Pediatrics (June 2010) by Dr. Panagiota Kitsantas reported that being overweight or obese before getting pregnant meant that a mother’s future child was 1.4 times more likely to be overweight or obese by age four. This means that doctors who do preconception health screening have a big responsibility to help patients learn more about how their weight gain during pregnancy has both long- and shortterm implications.
From real life
Obviously, there are exceptions — such as medications with a side-effect of weight gain — that make it hard for a pregnant mom to control her weight. Antidepressants (such as SSRIS) are known to have this side-effect. Reducing or eliminating exposure during pregnancy to SSRIS becomes very complex and is not suggested when the benefits of taking SSRIS trump all other decisions.
Although pediatricians do not look after pregnant mothers, what happens during pregnancy matters a great deal later, after the delivering doctor or midwife hands the baby over to the pediatrician. In my own clinic, I suggest two websites to pregnant moms: fitpregnancy.com fittodeliver.com I also highly recommend that pregnant mothers take DHA (omega 3s) during pregnancy; a National Institutes of Health study suggests the ideal goal is 300 mg of DHA per day. (For more information on the benefits of DHA during pregnancy and lactation, see Dhaomega3.org.)
In Alberta, there are plans to provide better resources to doctors who care for pregnant mothers in terms of tracking weight gain during pregnancy. Currently not all pregnant patients have their growth tracked over time; ideally, doctors should use IOM growth charts that allow clinicians to track a pregnant mom’s weight gain.