NHS website - How much weight will I put on during my pregnancy?

How much weight will I put on during my pregnancy?

It depends on your weight before you become pregnant.

Weight gain in pregnancy varies greatly. Most pregnant women gain between 10kg and 12.5kg (22lb to 26lb), putting on most of the weight after week 20.

Much of the extra weight is due to your baby growing, but your body will also be storing fat, ready to make breast milk after your baby is born.

Putting on too much or too little weight can lead to health problems for you or your unborn baby.

Gaining too much weight

Putting on too much weight can affect your health and increase your blood pressure. However, pregnancy is not the time to go on a diet, as it may harm the health of the unborn child.

It’s important that you eat healthily.

Gaining too much weight can increase your risk of complications. These include:

  • gestational diabetes: too much glucose (sugar) in your blood during pregnancy can cause gestational diabetes, which increases your risk of having a large baby
  • pre-eclampsia: a rise in blood pressure can be the first sign of pre-eclampsia; although most cases are mild and cause no trouble, pre-eclampsia can be serious 

Gaining too little weight

Gaining too little weight can cause problems such as premature birth and a baby with a low birth weight (less than 2.5kg or 5.5lb at birth). It can also mean your body is not storing enough fat.

Lack of weight gain can be related to your diet and weight before you become pregnant.

However, some naturally slim women stay slim while they’re pregnant and have healthy babies.

Staying active

Staying active is important while you’re pregnant, as it will prepare your body for labour and birth.

Keep up your normal daily activity or exercise (unless you’ve been advised by your midwife or GP not to exercise).

Advice about your weight

Your midwife or GP may have special advice for you if you weigh:

  • more than 100kg (about 15.5st)
  • less than 50kg (about 8st)

If you’re concerned about your weight or any other aspect of your health while pregnant, ask your midwife or GP for advice.

Read the answers to more questions about pregnancy.

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