Gaining Too Much Weight During Pregnancy Leads to Weight Issues Later On


If you’ve been pregnant, you’re no stranger to the many changes your body undergoes. Everything from raging hormones to strange hunger cravings hit you over the course of a pregnancy as part of your body’s efforts to adapt to the growing baby inside. Weight gain as the baby grows is just another part of the pregnancy process. But all that weight may be hard to get rid of, even once the baby’s gone. New research published this week has taken a closer look at weight gain in new and expecting mothers and has found that weight gain can be a real problem, especially in those who gain more than necessary during their months of pregnancy.

Is weight gain during pregnancy normal?

Weight gain should occur in every pregnancy and it should be more than just the weight of the baby. The placenta, which draws nutrients and oxygen from the mother to feed to the baby, grows with the baby and can account for at least a few additional pounds. The uterus also grows in size and mothers often gain water weight as the amount of blood in their system goes up. Expecting mothers also tend to gain a little bit in the form of fat stores, which is the body’s way of making sure enough energy is around to give birth and breastfeed. With that said, there are ranges of normal weight gain during pregnancy. How much weight you’ll need is mostly based on how much you weigh at the beginning of the pregnancy.

  • Underweight women (BMI under 18.5) should gain 28 to 40 pounds or about a pound per week
  • Normal weight women (BMI 18.5 to 25) should gain 25 to 35 pounds or a little less than a pound per week
  • Overweight women (BMI 25 to 30) should gain 15 to 25 pounds or a little over a half pound per week
  • Obese women (BMI over 30) should gain 11 to 20 pounds or about a half pound per week

Why did the researchers want to know about weight after birth?

While weight gain during pregnancy is normal, your body should eventually shed most of that weight once the baby’s gone and breastfeeding is over. The problem is this isn’t the case for some women. Some of those extra pounds may disappear with the pregnancy, but some of them may stick around for good in some women. Some pregnant women also gain more than the recommended amount during their pregnancy. Unfortunately, that weight can have health consequences just like any other weight gain, even if the initial gain was well intended. The research team wanted to know which women were likely to gain more weight than needed during pregnancy and who was more likely to hold onto the pounds years after the birth of their baby.

How did the team test weight gain over time?

The researchers recruited more than 302 women from upper Manhattan in New York City. They targeted women of color since they are at higher risk for being obese but had been under represented in past research about weight gain during pregnancy. Most of the women were African American or Dominican between 18 and 40. The researchers gathered data on weight and asked about health conditions like HIV, diabetes, heart disease and a variety of others. They followed the women for an average of seven years after birth to see whether they lost the weight they gained during pregnancy.

What did the researchers find?

The data showed that women who are normal weight or on the low end of overweight are those most at risk for hanging onto the pounds long after birth. Those most likely to gain the weight and keep it on were those who gained more than they needed during pregnancy. Women who were normal weight before pregnancy but gained more than prescribed were four times more likely to be obese in the years after than those who gained a normal amount. Even those who didn’t end up obese tended to have higher BMIs than women with normal pregnancy weight gain relative to where they started.

What does this mean for me?

Weight gain is normal, expected and necessary during pregnancy as long as it falls in the expected range for your BMI. You should never aim to avoid weight gain or to lose weight while you’re pregnant. What this study shows us is that gaining too much weight can stick with you well after the birth, especially if you’re in the normal BMI range. If you’re pregnant, make sure to discuss with your obstetrician what amount of weight gain is right for you and keep an eye on it, even when you’re craving a second serving of ice cream. The goal is to gain only as much as the baby needs to be healthy. Anything more may be with you for years to come.