Berger DS, West EH. Nutrition during pregnancy. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe’s Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 6.
Bodnar LM, Himes KP. Maternal nutrition. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 12.
As your baby grows, you will gradually gain weight. Gaining less or more weight than is recommended can have health implications for you and your baby, such as too much weight gain increasing the risk of gestational diabetes. If you have concerns about how much weight you are gaining (or not) in your pregnancy, discuss this with your doctor or midwife.
What is normal weight gain in pregnancy?
How much weight you gain will depend on how much you weighed before your pregnancy.
To calculate how much you should gain, first work out your pre-pregnancy body mass index (BMI). The formula for calculating BMI is:
Your pre-pregnancy weight (in kilograms) divided by the square of your height (in metres).
So if you weighed 68kg and you’re 1.7m tall, your BMI calculation would be 68 / 1.7 x 1.7 = 23.5.
You can use the healthdirect BMI calculator to work out your pre-pregnancy BMI.
If your BMI was 18.5 to 24.9, you were in the healthy weight range before becoming pregnant, and ideally you should gain between 11.5kg and 16kg: 1 to 1.5kg in the first 3 months then 1.5 to 2kg each month until you give birth.
If you were above the healthy weight range, you should gain less. If you are below the healthy weight range, you should gain more.
Your weight gain can also be affected by:
- carrying twins
- having morning sickness
Talk to your doctor about what’s the best weight gain for you.
Why am I gaining weight?
Not only is your baby growing, but your body is also developing extra body tissue. You will put on weight because:
- your breasts grow larger
- your uterus grows bigger
- there is amniotic fluid around the baby
- the placenta grows larger
- your body creates extra blood and fluid
What are the problems with gaining too much weight?
Your weight gain will be monitored throughout your pregnancy. If you gain more than 16kg, you and your baby could be at greater risk of complications such as:
- gestational diabetes
- hypertension
- caesarean section
- having a large baby (macrosomia)
- stillbirth
Babies born to mothers who put on too much weight are more likely to develop overweight and obesity in later life, develop more health problems, and be born with heart disease (especially if you smoke as well).
Managing your weight gain
You can help put on the right amount of weight by:
Make sure you know which foods are safe to eat during your pregnancy.
How much more food should I eat?
It’s important to eat well when you’re pregnant to give your baby a healthy start. But you don’t have to ‘eat for 2’, as some well-meaning people may have suggested.
You’ll probably find you don’t need to consume too many extra kilojoules in the first 3 months. As your baby grows, an extra 1,400 to 1,900 kilojoules a day in the second and third trimesters is likely to provide a healthy weight gain. It’s best to add that extra kilojoules through healthy food. This includes fresh fruit and vegetables, wholegrain breads and cereals, legumes, lean meat, fish and low-fat dairy products.
You should check that your diet contains the nutrients that keep you healthy and that will give your baby a healthy start such as folic acid, iron, calcium, iodine and protein.
It’s important to avoid foods that are high in sugar and/or fat and that don’t provide any vitamins or minerals.
Keeping up your fluid intake is also important — it’s recommended you drink about 2L of water each day. Morning sickness can make you dehydrated, so talk to your doctor or health professional if you’re not retaining enough fluids.
How much should I exercise?
Unless your doctor advises otherwise, you can start or continue with regular exercise when you’re pregnant as long as you adjust your activity to suit your stage of pregnancy. About 30 minutes each day of walking, swimming or pregnancy exercise classes will help — but don’t do more than 20 minutes of fast physical activity at a time, to avoid overheating.
Walking, swimming, aqua aerobics and pregnancy exercise classes are good choices. They will help prevent you from putting on extra weight, reduce your risk of gestational diabetes, and make you fitter so you can cope with labour better.
Gaining enough weight to support your growing baby and have a healthy pregnancy is among the most important things you can do while you're expecting. But how do you know how much weight to gain during pregnancy?
Though it's by far an exact science, and every pregnancy is different, there are guidelines you can follow to track your pregnancy weight by week and by trimester so you know the general pace you can expect to follow.
But keep in mind that there's a wide range of normal when it comes to gaining weight during pregnancy. Rather than obsessing over pregnancy weight gain at home, your best bet is to go to all your prenatal doctor's appointments and make sure things are progressing as they should. Always check in with your health care provider if you have any questions or concerns about your weight gain.
Read on for more about how much weight to gain American College of Obstetricians and GynecologistsWeight Gain During PregnancySee All Sources [1] during each week and trimester of pregnancy.
How much weight should you gain when you're pregnant? Check our pregnancy weight gain chart
You may have heard that you should gain 25 to 35 pounds while you're pregnant. But that range is for people whose body mass index (BMI) falls into the "normal weight" category before pregnancy.
Your BMI can give you an idea of how much weight you'll need to gain Centers for Disease Control and PreventionWeight Gain During PregnancySee All Sources [2] while you're expecting. See the breakdown in this helpful pregnancy weight gain chart:
If you're carrying multiples, the recommended weight gain for twins is as follows:
Using BMI to measure pregnancy weight gain, general weight gain and body type has become controversial, and some believe it's a flawed method of tracking a person's health. However, the American College of Obstetricians and Gynecologists (ACOG), the Centers for Disease Control and Prevention (CDC) and other major medical organizations continue to to use it, so we also rely on it in our pregnancy weight gain chart.
Just remember that there are a host of factors aside from your pre-pregnancy BMI that contribute to how much weight you may gain during pregnancy, as well as to your overall health. Always talk to your health care provider if you have any questions or concerns.
Pregnancy weight breakdown
Ever wonder where the pregnancy weight goes? It may feel like it’s all in your belly, but that’s not actually the case. For a 30-pound pregnancy weight gain, here’s the approximate breakdown:
Baby: 7.5 pounds
Placenta: 1.5 pounds
Amniotic fluid: 2 pounds
Uterine enlargement: 2 pounds
Maternal breast tissue: 2 pounds
Maternal blood volume: 4 pounds
Fluids in maternal tissue: 4 pounds
Maternal fat stores: 7 pounds
You need to gain weight in all these areas to have a healthy baby and pregnancy, and to prepare your body for breastfeeding if you’re planning on doing so.
Average weight gain during pregnancy by trimester
The process of putting on pounds throughout your pregnancy is not an exact science. But gradual weight gain is important, since your baby needs a steady supply of nutrients and calories to grow during her stay in the womb.
Your pregnancy weight gain timeline will depend on a variety of factors, such as your metabolism, activity level and genetics. It’s just one more reason why it’s important to keep up your doctor appointments throughout your pregnancy.
Here's what ACOG recommends for each trimester for those with a pre-pregnancy BMI of between 18.5 to 24.9:
First trimester weight gain
Your baby is still tiny, which means you may not need to gain more than a total of 2 to 4 pounds. If you're suffering from morning sickness, you might gain less than that or even lose a little. That’s okay, and you can make up for those pounds over the following six months.
On the other hand, if you have strong pregnancy cravings, you may gain a little more during the first trimester. In any case, your practitioner will help you come up with a plan for the next two.
Second trimester weight gain
Morning sickness usually fades between weeks 12 and 16 of pregnancy — just as your baby starts to grow in earnest. During the second trimester, your pregnancy weight gain should ideally increase so that you add a total of about 12 to 14 pounds.
Third trimester weight gain
Baby’s weight will pick up steam in the last few months of your pregnancy, but yours may start to taper off for a net gain of about 8 to 10 pounds. Some women find their weight holds steady or even goes down during the ninth month, when ever-tighter abdominal quarters can make finding room for food a struggle. It’s perfectly normal if you lose a few pounds at the end of pregnancy.
Keep in mind that these are averages, not a hard-and-fast formula. There will be some weeks when you feel hungry all the time and others when eating much of anything will make your stomach turn. As long as your overall pregnancy weight gain is on target and you're gaining at roughly the rate you should be, you’re right on track.
How to maintain healthy pregnancy weight gain
Eating a well-balanced, pregnancy-friendly diet can help you maintain healthy pregnancy weight gain. Focus on nutritious, satisfying foods that are rich in healthy fats or protein, such as nuts, beans, legumes, fatty fish, lean meat and dairy.
Also choose plenty of filling sources of fiber, like fresh veggies, fruits and whole grains. Try to limit your intake of overly processed, fried or sugary foods, which contain less nutrients for you and your baby.
In addition to giving you energy, a nutrient-rich diet fuels the incredible growth your baby is doing, including the development of her bones, brain, skin, eyes and digestive system.
You may want a rough daily estimate of your calorie needs during pregnancy. Base your pregnancy calorie goals on approximately how many calories you were eating before you got pregnant, with the daily amount increasing each trimester:
First trimester: You likely won't need extra calories yet, unless you started your pregnancy underweight.
Second trimester: Add about an additional 300 to 350 calories per day to your pre-pregnancy diet.
Third trimester: You'll need about 500 calories more per day than you were eating before you conceived.
If you’re carrying multiples, you can add about 300 calories per baby to these counts.
If you were underweight, overweight or obese before you got pregnant, talk to your doctor. You may need to consume more or fewer calories.
All that said, you don’t need to maintain a detailed log of your food intake. And while you can weigh yourself at home if you'd like to keep track of your weight gain, it’s also okay to wait until your regular prenatal checkups if you prefer.
Has your weight crept up faster than expected? Never diet during pregnancy, which can deprive your baby of essential nutrients she needs to grow, or take appetite-suppressing pills, which can be dangerous.
Instead, check in with your doctor. No matter what your situation is, your practitioner can provide personalized recommendations for your weight gain and daily caloric intake.
When to call the doctor
It’s always a good idea to check with your doctor if you’re concerned about weight gain. This is a conversation OB/GYNs and midwives are used to having, and they can help you find ways to hit your goals — or refer you to someone else (like a registered dietitian) for additional support.
Also check with your practitioner if you gain:
More than three pounds in any one week in the second trimester (sudden pregnancy weight gain can be a sign of preeclampsia)
More than two pounds in any week in the third trimester
No weight for more than two weeks in a row during the fourth to eighth months
It’s common to worry about losing weight after pregnancy, but try your best not to stress about it. You'll lose a lot of the baby weight naturally early on, and there are plenty of healthy ways to drop the rest gradually, including eating a nutrient-dense postpartum or breastfeeding diet, taking your baby out for regular stroller walks, and incorporating fitness (such as signing up for a baby-and-me yoga class or joining a gym) once you’re cleared to exercise.
Try not to focus too much on the ups and downs of pregnancy weight gain as long as you’re generally on track. And if pounds suddenly appear out of nowhere (or don’t appear at all), reach out to your doctor for guidance.