Pregnancy weight gain

Weight gain is a normal part of pregnancy. The UK sets no target ranges, so this uses the US National Academy of Medicine (IOM) ranges that NICE points to.

Your details

A typical gain by week 24

10 lb to 1 st 3 lb

US range for a pre pregnancy BMI of 24.5; the UK sets no target

UK guidanceNICE NG247 sets no target ranges and suggests no routine weighing
Typical total by birth (US range)1 st 11 lb to 2 st 7 lb
From week 13, a typical week0.4 to 0.5 kg

These are American ranges (IOM 2009, now the National Academy of Medicine). The UK does not set official targets, and the NHS says pregnancy is not the time to diet. Gain is rarely steady, and much of it is your baby, placenta, fluid and blood. Your midwife will weigh you if there is a reason to and will say if anything needs a closer look.

If worries about eating or weight are getting on top of you in pregnancy, tell your midwife. Beat (0808 801 0677) also supports people in pregnancy.

The working

BMI first, then the week

10 st 7 lb at 5 ft 5 in is a BMI of 24.5. The American IOM ranges suggest 0.5 to 2 kg in the first trimester, then 0.35 to 0.5 kg a week. At 24 weeks that is about 4.4 to 7.5 kg (9 lb 8 oz to 1 st 2 lb), on the way to 11.5 to 16 kg by birth.

Your gain so far

Where you are now, and twins

Add your weight now and we compare the gain with the typical range for your week. From 10 st 7 lb, 11 st 9 lb at 24 weeks is a gain of 1 st 2 lb (7.3 kg), within the 4.4 to 7.5 kg range. Gain comes in bursts, so being outside the range at one check is common.

For twins the same US report gives provisional totals by birth: 16.8 to 24.5 kg for a BMI of 18.5 to 24.9, 14.1 to 22.7 kg for 25 to 29.9 and 11.3 to 19.1 kg for 30 or more. There is no range below 18.5, and your care team will guide you.

Where the weight goes

Mostly not fat

Part	Roughly
Baby	3.5 kg
Placenta and fluid	1.5 kg
Extra blood and fluid	3 kg
Womb and breasts	1.5 kg
Stores for feeding	2 to 3 kg

The UK approach

No targets

NICE guideline NG247 (January 2025, which replaced PH27) says there is uncertainty about the best weight change in pregnancy, so it sets no UK ranges and asks midwives not to weigh routinely unless there is a clinical reason. If you are interested in monitoring, NICE points to the US National Academy of Medicine totals by pre pregnancy BMI, which is what this page shows. The NHS says most women gain 10 to 12.5 kg, mostly after week 20, and that pregnancy is not the time to diet. Eating well and staying active as you can is what matters; extra calories are only needed in the last trimester (about 200 a day).

Read with care

What this cannot tell you

Your pregnancySwelling, sickness and twins all change the picture.
Health targetsThese are ranges, not goals.
Eating worriesIf food or weight is troubling you, tell your midwife.

Questions

Common questions

How much weight should I gain in pregnancy?

Typical totals are 11.5 to 16 kg for a healthy BMI, but the UK sets no target.

Is it OK to diet while pregnant?

No. The NHS says pregnancy is not the time to go on a diet. Eating healthily and staying active is the focus.

Does the NHS have pregnancy weight gain targets?

No. NICE NG247 sets no UK ranges. If you want to monitor, it points to the US National Academy of Medicine ranges used here.

Do I need to eat for two?

No. About 200 extra calories a day in the last trimester only.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.