Weight gain can be a sensitive topic during pregnancy. Are you gaining enough? Too much? Some weight gain is necessary for a healthy pregnancy and baby, but your ideal weight varies depending on your pre-pregnancy weight.
Your weight gain is significant and a reason your provider will weigh you at every prenatal visit. It can give insight into potential health conditions and indicate how your body accommodates your baby and how well it grows. If you are pregnant, you may be curious about typical weight gain during pregnancy, how fast you should gain it, and where the weight goes.
When Do You Start Gaining Weight During Pregnancy?
Each woman’s weight gain trajectory during pregnancy is different. You may start gaining weight early in the first trimester, or it may not happen until you are further along. It depends on your baseline weight, your appetite, your activity level, hormones, how many fetuses, and more. In the first 12 weeks of pregnancy, you may gain no weight or somewhere between 1 and 5 pounds total.1
Proper nutrition and hydration during pregnancy are essential. However, this can be difficult to achieve, especially if you are experiencing morning sickness. Sometimes, the most important thing you can do in early pregnancy is eat whatever you can tolerate whenever you can. Focus on eating whole, nutrient-dense foods whenever possible, and be sure you are taking a quality prenatal vitamin to fill in any gaps in your diet.
The American College of Obstetricians and Gynecologists recommends consuming no extra calories above your baseline during the first 12 weeks of pregnancy.2 For a sedentary woman at a healthy pre-pregnancy weight, this means you should consume around 1,800 calories per day in the first trimester.3
As you progress through pregnancy, your caloric intake must increase to support healthy weight gain for pregnancy and baby. The American Pregnancy Association recommends consuming 2,200 calories daily during the second trimester. In the third trimester, this number increases to 2,400 calories per day.3 ACOG recommends an extra 340 calories daily in the second trimester and about 450 extra per day in the third trimester.1
How Much Weight Should You Gain During Pregnancy?
The total amount of weight you should gain and the rate at which you gain the weight during pregnancy varies highly among individuals.
The recommended total weight gain during pregnancy ranges from 11 pounds to 40 pounds or more, depending on your starting weight, body mass index, and number of babies you carry.3,4
While weight gain in the first trimester should be minimal, gaining weight weekly during the second and third trimesters is recommended. Weekly weight gain from weeks 12 to 40 of pregnancy should be between half a pound and a pound and a half, depending on the starting weight and how much you gained in the first trimester.1
Although weight gain can be averaged out over pounds per week, weight gain may not be perfectly linear. You may gain no weight one week and then multiple pounds the next. Just like children, babies in the womb have growth spurts.5
If your weight spikes drastically in one week, particularly in the third trimester, this can be a sign of preeclampsia. Look out for weight gain of 3 to 5 or more pounds in a week.6 While it can be normal to experience ebbs and flows, close monitoring and regular weight checks are essential.
Pregnancy Weight Gain Numbers
Suggested weight gain during pregnancy is based on your pre-pregnancy body mass index or BMI. Body mass index is taken by dividing your weight in kilograms by your height in meters squared (kg/m2).
Suggested pregnancy weight gain charts for rate of weight gain and total weight gain are included below. Keep in mind that these numbers assume a 1- to 5-pound total weight gain during the first trimester.1
Pregnancy Weight Gain by Week in Second and Third Trimesters
Pre-pregnancy BMI: Pounds per week
- Underweight (less than 18.5): 1-1.3
- Normal weight (18.5-24.9): 0.8-1
- Overweight (25-29.9): 0.5-0.7
- Obese (30+): 0.4-0.6
Total Healthy Weight Gain
Pre-pregnancy BMI: Singleton pregnancy weight gain/Twin pregnancy weight gain in pounds
- Underweight (less than 18.5): 28-40/unknown
- Normal weight (18.5-24.9): 25-35/37-54
- Overweight (25-29.9): 15-25/31-50
- Obese (30+): 11-20/25-42
Where Does the Weight Go?
The location of some weight gained during pregnancy is obvious — your baby has weight to it. However, there are also many other factors accounting for pregnancy weight gain.
The uterus grows into a huge muscle, and the placenta has a significant weight to it by the end of pregnancy. A mother also produces extra blood during pregnancy to supply nutrients and oxygen to the uterus and placenta, which adds weight. She also retains additional fluid due to hormones. Finally, she stores extra fat to aid milk production during breastfeeding postpartum.7
Here is an example breakdown of where pregnancy weight is distributed:3
- Baby: 7-8 pounds
- Placenta: 1-2 pounds
- Amniotic fluid: 2 pounds
- Larger uterus: 2 pounds
- Increased blood volume: 3-4 pounds
- Increased fluid volume: 2-3 pounds
- Fat storage: 6-8 pounds
- Larger breasts: 1-3 pounds
These are averages and ranges that account for women of normal pre-pregnancy BMI but can vary widely.
What If You Are Losing or Not Gaining?
Healthy and sufficient weight gain during pregnancy is essential. If you are not gaining weight during pregnancy, your baby may be at risk of being small for gestational age or preterm delivery.8
If you are still in your first trimester and have not gained or lost a few pounds, this is not usually cause for concern. Babies at this early stage of development do not rely as heavily on mom’s increased calories.8
If you are in your second or third trimester and are not gaining weight, ensure you consume enough calories to feed your body and your baby. For many pregnant women, their appetites increase to accommodate increased energy needs. Remember that pregnancy weight gain will be lower if your pre-pregnancy weight is higher. Pregnancy is not the time to lose weight, so ensure you are not restricting calories. At the same time, gaining too much weight can also increase health risks to you and your baby.8
If you feel confident that you are consuming enough calories and still not gaining appropriate weight, check in with your care provider. They can do an ultrasound to check on your baby’s growth and do any necessary tests if there are any concerns.
Pregnancy weight gain is just one data point indicating a healthy baby. Your weight is essential, but it is not the only important factor. How you feel physically and mentally affects your pregnancy, so try not to obsess over the numbers. As always, talk to your provider if you have concerns, and they can reassure you or assess your and your baby’s health status.