Weight Gain in Pregnancy

by on June 11, 2012

in Weekly


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 know it is wrong to “eat for two” but even so, I tend to gain weight easily during pregnancy.

How much weight a woman gains during pregnancy impacts 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 labor, enduring longer labor and ending up with delivering a baby via a cesarean section.

From the fetus’ perspective the birth weight may be higher and later in life the baby is 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 1/3 of pregnant patients who were at a normal weight before pregnancy gain more weight than what experts recommend in their guidelines. Close to ½ of pregnant patients who were already overweight before they got pregnant gain to much weight during pregnancy.

Every few years experts review the latest research and recommend guidelines of the ideal weight gain during pregnancy. The Institute of Health (IOM) recommendations remain the gold standard at this time and have been adopted by Health Canada and various provinces in Canada.

The 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 weigh women should gain 25 to 35 lbs in total during their pregnancy (11.5 to 16kg)

—Overweight women (BMI of 25-29.9) should gain 15-25lbs (7-11.5kg)

—Obese women (BMI over 30) should gain a total of 11-20 lbs (5 to 9kg)

The IOM recommends that during the 2nd and third trimesters normal weight women gain 1 lb per week (0.4kg); overweight women 0.6lb per week (0.3kg) and obese women 0.5lb per week (0.2kg)

Overall the rate of weight gain during pregnancy of 7lb per month (3kg) is considered excessive.

Dr David Ludwig, a Boston-based researcher and obesity expert in children published data in the Lancet which got the attention of his peers when it comes to preventing childhood obesity. Ludwig’s data convincingly made 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 what will happen later in life. This is independent of genetics. The exact mechanism why the stage may be set for life is unclear.

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 4. This means that doctors who do preconception health screening have a big responsibility to identify and help patients learn more about how their weight gain during pregnancy has both long and short term implications.

Dr Ludwig commented that women tend to be especially motivated to live healthy 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%,reduce their coffee intake or try to get more rest—all based on instinctively wanting to give their offspring a healthy start in life)

Obviously not all pregnant patients follow the above line of thought and there are exceptions which makes it hard for a pregnant mom to control her weight. One such exception is a patient who also takes medications which have side effects of weight gain. Antidepressants (such as a SSRI) 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 a SSRI trumps 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 mom’s who are pregnant: www.fitpregnancy.com and www.fittodeliver.com I also highly recommend that pregnant mothers ingest DHA (omega 3s) during pregnancy, based on a NIH study which suggest the ideal goal is 300mgsDHA/day. (For more information on the benefits of DHA during pregnancy and lactation, see www.DHAomega3.org)

In Alberta there are plans to provide better resources to doctors who care for pregnant mothers in terms of tracking the weight gain during pregnancy. Currently not all pregnant patients have their growth tracked on a graph over time. Ideally doctors should use growth charts by the IOM which allows clinicians to track a pregnant mom’s weight gain throughout pregnancy.

Some clinicians use the 5-10-10 rule (gain 5lbs in the first trimester, 10lbs in the second and 10lbs in the third)  However, the IOM recommendations are the gold standard at this point.



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