Pregnancy Weight Gain: How Much Should You Gain? (Chart by BMI)

Healthy pregnancy weight gain depends on your pre-pregnancy BMI: CDC and Institute of Medicine ranges for one baby are 28 to 40 pounds if underweight, 25 to 35 pounds at a normal weight, 15 to 25 pounds if overweight and 11 to 20 pounds with obesity.

How much weight you should gain during pregnancy is one of the first questions people ask, and the answer is a range, not one number. Your starting BMI, whether you are carrying twins and your own health all shape your target, and your provider helps you set it.

Below you will find the BMI chart for singletons and twins, the usual pattern by trimester, where the weight actually goes, extra calorie needs, eating and movement that support you, and the signs that mean you should call.

How Much Weight Should You Gain During Pregnancy?

These numbers come from the 2009 report Weight Gain During Pregnancy: Reexamining the Guidelines, written by an Institute of Medicine (IOM) and National Research Council committee. The CDC and Mayo Clinic publish the same ranges, and Mayo Clinic stresses they are general guidelines.

Pregnancy Weight Gain Chart by BMI: One Baby and Twins

Find your pre-pregnancy BMI category (your weight before you were pregnant, compared with your height), then read across. If you do not know your BMI, your provider can calculate it at your first prenatal visit.

• The obese row: Mayo Clinic labels it BMI 30 or more. The CDC chart labels it 30.0 to 39.9, so if your BMI is 40 or higher, ask your provider what range fits you.
• Twins: the IOM committee called its twin ranges provisional and could not set one for underweight women.
• Triplets or more: the CDC says to talk with your health care provider about your weight gain goal.

The CDC also publishes free printable weight gain trackers for each BMI category, for one baby and for twins.

Pregnancy Weight Gain by Trimester and Week

Weight gain is not spread evenly across 40 weeks. Most of it comes after the first trimester.

Gaining little early on usually fits the pattern. Our first trimester guide covers what else is going on in those early weeks. For the steadier climb that follows, see our second trimester and third trimester guides.

Week to week, the number may not rise in a smooth line. What matters is the overall pattern against your range, which you and your provider review together. Pages like 20 weeks pregnant and pregnant belly by month show how bodies change along the way.

Where Does Pregnancy Weight Go?

Most of the gain is your baby and the tissue and fluid that support your baby.

Risks of Gaining Too Little or Too Much

Gaining well outside your range, in either direction, is linked with problems.

• Gaining too little: MedlinePlus says too little gain can cause problems for both mother and baby. Mayo Clinic says that if you started underweight, gaining weight is crucial, because without it your baby might be born early or smaller than expected. The IOM committee found that a baby being small for gestational age was linked with harm for the infant.
• Gaining too much: Mayo Clinic lists a baby born much larger than average, birth complications such as shoulder dystocia (the baby’s shoulder getting stuck after the head is delivered), and keeping extra weight long after pregnancy. MedlinePlus notes that a larger baby can sometimes complicate delivery. The IOM committee linked a baby being large for gestational age with consequences for both baby and mother, such as a cesarean delivery.

These are risks, not predictions, and you are not alone if your gain does not match the chart: the CDC reports that only about 1 in 3 women gained the recommended amount in a previous study, with about 1 in 5 gaining below and about 1 in 2 gaining above.

If your gain is moving faster or slower than expected, talk it through with your provider, who can look at your whole picture.

How Many Extra Calories Do You Need While Pregnant?

Sources differ slightly, but agree the first trimester needs little or nothing extra.

To put that in food terms, Mayo Clinic’s example of about 300 extra calories is a sandwich and a glass of skim milk. MedlinePlus gives rough daily totals of about 1,800, 2,200 and 2,400 calories by trimester. Treat any number as a starting point to discuss, not a rule to count against.

Healthy Eating While Pregnant

The CDC suggests a balanced plate built on whole grains, vegetables, fruits, low-fat dairy and lean protein, while limiting added sugars and solid fats. MedlinePlus adds a few practical swaps:

• Fill up on fresh fruits and vegetables, whole grains and low-fat dairy.
• Choose water more often than soda and fruit drinks.
• Bake, broil, grill or boil foods more often than frying.
• Keep sugary drinks, junk food and high-fat foods to a smaller share of what you eat.

The CDC also points pregnant people to food safety guidance.

A daily prenatal vitamin fills gaps that food alone may not cover; our prenatal vitamins guide explains what to look for. If you are still planning, how to prepare for pregnancy covers the steps that help before you conceive, including a preconception visit.

If you have had an eating disorder, or tracking food and weight feels stressful, tell your provider. You can ask not to see the number at weigh-ins, and MedlinePlus suggests asking your provider for help planning a healthy diet.

Staying Active During Pregnancy

Movement supports healthy pregnancy weight gain and much more. The CDC recommends at least 150 minutes per week of moderate-intensity aerobic activity during pregnancy and the postpartum period, such as 30 minutes on 5 days. Shorter sessions count, and the CDC adds that some activity is better than none.

The CDC lists benefits including a lower risk of excessive weight gain and gestational diabetes, and says activity does not increase the risk of low birth weight, early delivery or early pregnancy loss.

• Good options: brisk walking, some forms of yoga, water aerobics and bike riding (CDC). Mayo Clinic also names swimming.
• If you were already active: the CDC says women who already run can usually continue vigorous activity.
• After the first trimester: the CDC says to avoid activities that require lying flat on your back.
• Check in first: the CDC says moderate activity can begin or continue unless there is a medical reason to avoid it; ask your provider before starting something new.

Weight Gain With a Higher BMI

If you started pregnancy with a BMI of 25 or higher, the recommended range is smaller (15 to 25 pounds for overweight, 11 to 20 pounds for obese, per the CDC), and Mayo Clinic describes a slower pace of about half a pound per week after the first trimester. A smaller range is not a judgment; it is simply the range the guidelines set for that starting point.

What it does not mean is dieting. MedlinePlus is direct: do not diet or try to lose weight during pregnancy. Focus on nourishing food and staying active instead. Any plan to gain less than your range, or to lose weight, should come only from your own clinician.

Mayo Clinic also notes that a higher BMI before pregnancy raises the chance of conditions such as gestational diabetes, preeclampsia and cesarean birth. Your provider may watch for these more closely. Our preeclampsia guide explains the warning signs. You deserve respectful care at every size.

Weighing In at Prenatal Visits

Expect to step on a scale at most prenatal appointments. The CDC advises tracking pregnancy weight gain at the beginning of pregnancy and regularly throughout, working with your provider on your goal.

• Your first visit: sets the baseline. Your pre-pregnancy weight and height set your BMI category.
• Later visits: show the trend. A single high or low reading is less important than the direction over several weeks.
• Your options: you can ask to be weighed facing away from the number, or to discuss the trend instead of the reading.
• Home weighing: is optional. The CDC trackers let you plot your gain; if it adds stress, leave it to the office.

Mention anything that affects your weight, such as nausea that makes it hard to eat, appetite changes or swelling.

Postpartum Weight: What Happens After Birth

Your baby and the placenta are delivered at birth, so part of the gain is gone that day. MedlinePlus says the extra weight generally comes off after delivery, and Mayo Clinic says healthy habits during pregnancy can make it easier afterward.

There is no deadline. The IOM committee recommended diet and activity counseling for all postpartum women, aiming to return to pre-pregnancy weight within the first year, not six weeks.

The CDC’s 150 minutes per week target applies to the postpartum period too, and it says activity in the first year after delivery can ease postpartum depression symptoms. Get your provider’s go-ahead first; our postpartum workout plan and 4th trimester guide cover recovery in the early weeks.

Related Betteroo Guides

• First Trimester Guide
• Second Trimester Guide
• Third Trimester Guide
• Pregnant Belly by Month
• Prenatal Vitamins
• Preeclampsia

When to Call Your Doctor or Midwife

Some changes cannot wait for your next visit. MedlinePlus lists these as possible signs of preeclampsia, a serious blood pressure condition. Contact your provider right away if you notice:

• Sudden weight gain: a gain over 1 to 2 days, or more than 2 pounds in a week.
• Swelling of your face or hands: or around your eyes. Some swelling of the feet and ankles is normal in pregnancy.
• A headache: that does not go away or gets worse.
• Vision changes: blurry vision, flashing lights or spots, sensitivity to light, or temporary loss of vision.

MedlinePlus also lists severe symptoms: trouble breathing, belly pain on the right side below the ribs, urinating less than usual, nausea and vomiting, and feeling lightheaded or faint. If symptoms are severe or you cannot reach your provider quickly, go to labor and delivery or the nearest emergency room, or call 911.

MedlinePlus notes that preeclampsia can also start after delivery, with risk continuing for up to 6 weeks, so the same signs matter postpartum. Call during office hours if you are gaining much faster or slower than your range or cannot keep food down. This article is general education, not medical advice.

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