How Much Weight Should You Gain in Pregnancy?

Gaining weight is a normal, healthy part of pregnancy. How much depends mainly on your weight before pregnancy. Tracking your weight helps you and your provider spot changes early and stay within the range that is right for you, which is exactly why the Prego app has a weight tracker that shows your recommended range.

How much weight should I gain?

These are the ranges recommended by the US National Academies (IOM) and ACOG for a single baby, based on your pre-pregnancy BMI.

Pre-pregnancy BMI	Total weight gain	Weekly gain in 2nd and 3rd trimesters
Under 18.5 (underweight)	28 to 40 lb (12.5 to 18 kg)	About 1 lb (0.5 kg)
18.5 to 24.9 (healthy)	25 to 35 lb (11.5 to 16 kg)	About 1 lb (0.4 kg)
25 to 29.9 (overweight)	15 to 25 lb (7 to 11.5 kg)	About 0.6 lb (0.3 kg)
30 or more (obese)	11 to 20 lb (5 to 9 kg)	About 0.5 lb (0.2 kg)

If you are expecting twins, the ranges are higher, for example 37 to 54 lb (17 to 25 kg) for a healthy pre-pregnancy BMI.

To see your own range for this week, use our pregnancy weight gain calculator.

When does pregnancy weight gain happen?

Most people gain only 1 to 4.5 lb (0.5 to 2 kg) in the first trimester, and some lose a little because of nausea. Most of the gain happens in the second and third trimesters, at a fairly steady weekly rate.

Where does the weight go?

For a total gain of around 30 lb (13.5 kg), it breaks down roughly like this:

	Approximate weight
Baby	7.5 lb (3.4 kg)
Placenta	1.5 lb (0.7 kg)
Amniotic fluid	2 lb (0.9 kg)
Larger uterus	2 lb (0.9 kg)
Breast tissue	2 lb (0.9 kg)
Extra blood	4 lb (1.8 kg)
Extra fluid	4 lb (1.8 kg)
Fat stores for breastfeeding	7 lb (3.2 kg)

Why it matters

Gaining within your range lowers the risk of complications. Gaining too much is linked to gestational diabetes, high blood pressure, a larger baby and a harder birth. Gaining too little is linked to preterm birth and a smaller baby. But the ranges are guides, not pass-or-fail targets. Your provider looks at the overall pattern.

Tips for healthy weight gain

Eat for one and a bit. You need no extra calories in the first trimester, about 340 more a day in the second and about 450 more in the third.
Fill up on nutrient-dense food. Vegetables, fruit, whole grains, lean protein and dairy. See our pregnancy diet guide.
Cut back on sugary drinks, which add calories without filling you up.
Keep moving. Try our safe pregnancy exercises.
Weigh yourself regularly at the same time of day, such as once a week in the morning.

When to call your provider about your weight

Sudden weight gain, such as more than 2 lb (1 kg) in a week in the third trimester, especially with swelling of your face or hands, a headache or vision changes, can be a sign of preeclampsia. Call your provider straight away.

Frequently asked questions

Is it normal to lose weight in the first trimester?

A small loss from morning sickness is common and usually not a concern. If you can't keep food or fluids down, or are losing a lot of weight, contact your provider.

Should I diet if I'm overweight during pregnancy?

No. Pregnancy isn't the time to try to lose weight. Instead, aim for the lower gain range for your BMI with healthy food and gentle exercise, guided by your provider.

When will I lose the baby weight?

You lose about 10 to 13 lb (4.5 to 6 kg) at birth, and more in the following weeks as fluid leaves your body. Most people return close to their pre-pregnancy weight over 6 to 12 months. Breastfeeding can help.

Sources

General information only, not medical advice. Always follow the guidance of your doctor or midwife.

History of updates

October 21, 2026: Published.