How Much Should You Gain During Pregnancy?

Too much or not enough?

It’s a touchy question for many of the expecting moms I see: Just how much weight should you put on during pregnancy? Gaining too much or not enough when baby’s on board can have serious consequences for both mom and baby.

Body Mass Index (BMI) counts

How much weight you put on during pregnancy really depends on where your weight begins before becoming pregnant. Regardless of how much you weigh, every woman should expect to put on some weight.

Women, who are normal weight, meaning you have a BMI between 18 and 25, should gain 25-35 pounds during pregnancy. Those who are underweight, with a BMI less than 18 should gain more, about 30-40 pounds. And overweight women, those with a BMI over 30, should gain 10-20 pounds.

Too little weight

There’s a misconception among some women that if they don’t gain a lot of weight during pregnancy, they’ll get rid of their fat. Unfortunately, pregnancy doesn’t work that way. Not gaining weight means you’ll actually end up using your own muscle mass to feed your developing baby, and that’s not good. 

Not only is not gaining enough weight not good for mom, it’s not good for baby. Studies show not gaining enough weight during pregnancy can result in a low birth weight baby. That doesn’t just mean you will have a small baby. Low birth weight is tied to many significant, long-term negative neurologic problems.

Gaining too much

On the flip side, gaining too much weight during pregnancy has a host of problems of its own. Obesity and excessive weight gain are more common problems. Excessive weight gain puts you at a much higher risk for diabetes during pregnancy and after. These expecting moms are also at higher risk for hypertension, preeclampsia and significant delivery problems such as tears, vaginal laceration and even C-section. I stress to patients that “eating for two” does not mean doubling your calories.

Women who gain too much weight in pregnancy are at much higher risk for large babies. Those babies are disproportional, gaining a lot of weight in the abdomen, putting them at risk for shoulder dystocia. That can also mean permanent neurologic problems for baby. These babies also tend to have more problems after delivery with issues such as blood sugar and heat management.

So where does all that weight you gain during pregnancy go?

• Fetus – 7-8 pounds
• Fat stores – 7-8 pounds
• Increased blood volume – 3 pounds
• Fluid retention/swelling – 2-3 pounds
• Breasts – 1-3 pounds
• Uterus – 2 pounds
• Placenta – 1-2 pounds
• Amniotic fluid – 1-2 pounds

With that breakdown, most women will see a 12-15 pound loss just by delivering. Another 10 pounds is lost within the two weeks of having baby.

If you do not get back to your pre-pregnancy weight by six weeks postpartum, the weight is likely to stay. Pregnancy and motherhood are the times of a woman’s life when she may begin her battle with obesity. “Baby weight”, sleep deprivation and lack of exercise when kids are young are the trifecta potentially leading to life-long obesity.

Trust the process

At Methodist Physicians Clinic, we assure our patients that weight gain during pregnancy is simply part of the process of having a happy, healthy baby. And a healthy baby is worth all its weight in gold.