Pregnancy comes with a significant change in your shape, and of course a weight gain. But what’s an expected pace for weight gain? Where does all of that weight go? And how do you know how much weight to gain during pregnancy? Let’s see what the experts have to say.
Estimated reading time: 6 minutes
Table of contents
- Do I Have to Gain Weight During Pregnancy?
- How Much Weight Should I Gain During Pregnancy?
- Where Does The Weight Go?
- What’s a Normal Pace for Weight Gain During Pregnancy?
- Isn’t Pregnancy a Time to Indulge?
- When Weight Gain Becomes a Problem
Do I Have to Gain Weight During Pregnancy?
The short answer is yes, you must gain weight during pregnancy. Your baby needs to be properly nourished in order to grow and develop. Think about it this way: Your baby is growing, your blood volume is increasing, your uterus is getting bigger, and the placenta is getting bigger. If you aren’t gaining weight, then your body must be actually losing weight in order to balance all of those gains. And your body burning its own reserves — as is does when you’re losing weight — does not provide your little one with the chance for optimal growth and nutrition. It also doesn’t keep you at your strongest, which is key as you move toward labor and delivery.
In previous generations, women were sometimes advised to gain very little — sometimes as little as a mere 12 to 15 pounds (1)! Now we know much more about how much weight to gain during pregnancy, and we recognize that it’s not healthy for mother or baby to restrict weight gain so severely. The reality is, if you gain too little, you are more likely to have a premature baby (2) or a baby with low birth weight (less than 5 1/2 pounds). Unfortunately, these babies are more likely to have significant health problems after birth (3).
How Much Weight Should I Gain During Pregnancy?
So, the big question is how much weight is it ideal to gain during pregnancy. There is not one right answer to this question, because it largely depends on your weight before pregnancy. Your healthcare provider will first determine whether your prepregnancy weight fits into the category of underweight, normal weight, overweight, or obese. He or she may use a height/weight chart to determine this, or may calculate your BMI. BMI stands for body mass index, and is a measure of body fat based on height and weight. (3)
Average Pregnancy Weight Gain
Here’s a general guideline of what you should gain based on your prepregnancy weight:
- Underweight (BMI less than 18.5) – gain 28 to 40 pounds
- Normal weight (BMI 18.5 – 25) – gain 25 to 35 pounds
- Overweight (BMI 26 – 29) – gain 15 to 25 pounds
- Obese (BMI over 30) – gain 11 to 20 pounds (1)
While these are the currently accepted guidelines, you should always communicate with your provider about how much is appropriate for you. Each situation is different, and your doctor or midwife may take into account factors other than height, weight, and BMI. So, trust your caregiver’s recommendations.
Where Does The Weight Go?
You may be wondering what becomes of the extra weight you gain during pregnancy — after all, a baby is usually only around seven to eight pounds. If an average mom should gain 25 – 35 pounds, where does the rest of it go? Here’s an approximate breakdown:
- Baby – 7 to 8 1/2 pounds
- Placenta – 1 to 1 1/2 pounds
- Uterus – 2 pounds
- Amniotic fluid – 2 pounds
- Breasts – 1 pound
- Blood volume – 2 1/2 pounds
- Fat – 5 to 8 pounds
- Tissue fluid – 6 pounds (2)
As you can see, there is much more than just the weight of the baby. This is also why you don’t lose every bit of pregnancy weight directly after you deliver your baby. All of it serves an important purpose, though. Even the fat, which people often unnecessarily fear, is needed for what healthcare providers call “maternal stores” and to help establish breastfeeding.
What’s a Normal Pace for Weight Gain During Pregnancy?
Your doctor or midwife will likely check your weight at each prenatal visit to be sure that you’re gaining appropriately.
First Trimester Weight Gain
In the first trimester, an appropriate weight gain is typically about 1 to 5 pounds (2). (As we mentioned in our Week 16 Pregnancy post, some women don’t actually gain at all during the first trimester, or may even lose weight, due to morning sickness.)
Second & Third Trimester Weight Gain
In the second trimester, you’ll start to gain weight more quickly, as your baby grows and your blood volume and amniotic fluid increase. Through the second and third trimesters, women may gain around a pound a week, though this depends on your prepregnancy weight. An overweight or obese woman may only expect to gain 1/2 pound a week. (2)
Isn’t Pregnancy a Time to Indulge?
We’ve all heard the old expression that a pregnant woman is “eating for two.” While it is true that you’re nourishing yourself and your baby, this does not mean that you should eat as if you’re feeding another entire grown person. And while it may be tempting to eat all the snacks you want, or justify overindulging because weight gain during pregnancy is allowed, you should still keep an eye to eating healthfully.
Statistics show that nearly 45% of pregnant women gain more weight than recommended (1). Women who gain too much weight during pregnancy increase the risks of developing preterm labor, gestational diabetes, high blood pressure, or a large baby that can make it more difficult to deliver vaginally (2). They may also find it harder to lose the extra weight after baby is born. Make sure to eat foods that have a high nutritional value. Also, keep an eye on how you’re feeling, emotionally and physically, as you start a meal. If you’re fatigued, stressed, or anxious, you may be more likely to reach for sweets or foods high in empty calories (1).
When Weight Gain Becomes a Problem
There may come a time during your pregnancy when your doctor tells you that you’re gaining too much or too little weight. This isn’t a cause for panic. You simply need to work with your provider on a plan for how you can eat healthfully to bring your weight gain in line with what’s best for you and baby.
Never try to lose weight while pregnant. If you’ve gained more than considered ideal for your stage in pregnancy, simply focus on gaining at a healthier rate going forward. Don’t try to restrict your calories to get back to that “ideal” number. Just be sure you’re focusing on consuming reasonable portions of foods from the five major food groups, and cut down on empty calories and sugars, large portions, and second helpings. (3) Remember that what you eat is what your baby eats, and choose the best foods to nourish your baby’s growing body.
To learn more about healthy eating during pregnancy, visit the American Pregnancy Association’s Diet During Pregnancy page.
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- Glade, B.C., Schuler, J. (2011). Your Pregnancy Week by Week, 7th edition. First Da Capo Press
- Simkin, P. (2010). Pregnancy, Childbirth and the Newborn, 4th edition. Meadowbrook Press
- The American College of Obstetricians and Gynecologists. (2010). Your Pregnancy and Childbirth Month to Month, 5th edition.