How Much Weight Should I Gain During Pregnancy?

A Primer on Pregnancy Pounds

It's easier to justify the "eating for two" thing before you know exactly how much weight you're supposed to gain during pregnancy. But while thinking about your weight is a bummer when you're craving a third bowl of chips, monitoring your gain is an important part of making sure you have a healthy pregnancy. Establishing a specific weight target is something you should talk to your doctor about because it depends on your current weight and medical history. Most women should aim to gain no more than 40 pounds, taking in about 300 additional calories per day.

If You're Pregnant with One Baby

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How Much Should I Weigh Before I Get Pregnant?

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Your pre-pregnancy weight is a significant factor in determining the appropriate amount of weight for you to gain. The heavier you are when you get pregnant, the less weight you should gain. Adding too much weight puts you at risk of having a very large baby, which may cause complications during delivery. If you gain too little weight, your baby may be born underweight and be prone to illness and developmental delays.

Medical experts have developed weight guidelines based on body mass index, or BMI. (Your doctor can tell you your BMI, or you can use an online calculator to determine it.) These are just rough guidelines, though. Many women gain significantly more weight than they "should" and still have perfectly healthy pregnancies and babies.

A woman who is underweight (BMI 18.5 or less) should gain about 28 to 40 pounds during a healthy pregnancy. A woman of normal weight (BMI 18.5-24.9) should aim to gain between 25 and 35 pounds. An overweight woman (BMI 25-29.9) should gain 15 to 25 pounds, and an obese woman (BMI 30 and above) should try to gain no more than 11 to 20 pounds during pregnancy.

If You're Pregnant with Multiples

More babies need more calories, so if you're pregnant with multiples, you should expect to gain more weight than moms of singles do. Again, your doctor can help you figure out exactly what your target weight should be. These estimates are especially hard to pinpoint because moms of multiples often give birth before 40 weeks, so their pregnancies tend to be shorter than moms of single babies.

An underweight woman should gain between 50 and 62 pounds during a pregnancy with multiples. A woman of normal weight should gain between 37 and 54 pounds, and an overweight woman should gain 31 to 50 pounds. An obese woman should expect to gain 25 to 42 pounds while pregnant with multiples.

Your Weight, Week by Week

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My Body Fat Percentage & Pregnancy

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Pregnancy weight gain generally starts slow and steady. You may not gain anything in the first trimester. Some women even lose a little weight during this time. If you do gain, it probably won't be more than a few pounds.

Once the second trimester begins, expect to gain about one pound per week on average, or a little more if you're carrying multiples. It may appear in fits and starts, with no gain one week and a sudden increase the next. As long as you continue to gain weight slowly and steadily, you should be fine. But your doctor should also be tracking your weight, so bring it up if you have any questions or concerns.

Where Does the Weight Go?

A normal baby weighs less than 10 pounds, so where does the rest of that added weight go? Everywhere, as it turns out. Your placenta, amniotic fluid, increased breast tissue and uterus account for a weight gain of a few pounds each. A lot of the remaining weight is attributed to extra stores of blood, fat, protein and nutrients that your body creates to nourish your baby, keep up with your body's increased activity and prepare for breastfeeding later.