It's natural and healthy to put on weight during pregnancy. Your body needs to change to help you grow your baby and to give him the best start in life.
Your midwife will weigh you the first time you see her, which will be at your booking appointment. She will then work out your BMI. You will also be weighed during your third trimester, particularly if you have gained a lot of weight. Putting on more weight than you expected may affect your plan for labour.
To check how well your baby is growing, your midwife will measure the size of your bump. If the measurement is smaller or greater than average your midwife may suggest you have an ultrasound scan. A scan will give a better idea of how your baby is growing.
Your body mass index (BMI) measures your weight in relation to your height. It's an accurate way of telling whether or not your weight is in the healthy range. The amount of weight that you should put on in pregnancy depends on what your BMI was before you were pregnant.
There are no official UK guidelines for how much weight you should gain over your pregnancy. There is only general advice that most women put on somewhere between 10kg and 12.5kg (22lb to 28lb). You'll gain most of the weight after 20 weeks.
See below for average weight gain:
Weight in Pregnancy - optiMUM
| Pre-pregnancy BMI | BMI | Total Weight Gain | Rates of weight gain 2nd and 3rd trimester (average range/week) |
|---|---|---|---|
| Underweight | less than 18.5 | 13kg to 18kg (28lbs to 40lbs) | 0.5kg to 0.6kg (1lb to 1.3lb) |
| Normal weight | 18.5 to 24.9 | 11.5kg to 16kg (25lbs to 35lbs) | 0.4kg to 0.5kg (0.8lb to 1lb) |
| Overweight | 25 to 29.9 | 7kg to 11.5kg (15lbs to 25lbs) | 0.2kg to 0.3kg (0.5lb to 0.7lb) |
| Obese | 30 or more | 5kg to 9kg (11lbs to 20lbs) | 0.2kg to 0.3kg (0.4lb to 0.6lb) |
optiMUM Programme
It is estimated that over 50% of women of child bearing age are overweight or obese and almost 20% are obese when they conceive. The maternal and infant complications associated with excess body fat include increased risk of miscarriage, pre-eclampsia, gestational diabetes in mothers; and stillbirths, pre-term births and congenital abnormalities in the baby.
In addition, excess weight gain in pregnancy and poor weight management in the postpartum period are associated with chronic obesity related problems (e.g. diabetes) as well as increased risk of significant problems in subsequent pregnancies.
optiMUM is a healthy lifestyle intervention and is based on national recommendations for pregnant women with a BMI >30kg/m2. All women are advised of their BMI and of the maternal and fetal risks associated with obesity. Midwives will encourage you to be physically active and will provide information and support on dietary intake (eat well plate, portion frequency and size).
Pregnancy is not a time to diet but is a time to avoid excessive weight gain. It is not necessary to eat for two. Only 200 calories extra per day are required in the last three months of pregnancy.
In addition, excess weight gain in pregnancy and poor weight management in the postpartum period are associated with chronic obesity related problems (e.g. diabetes) as well as increased risk of significant problems in subsequent pregnancies.
optiMUM is a healthy lifestyle intervention and is based on national recommendations for pregnant women with a BMI >30kg/m2. All women are advised of their BMI and of the maternal and fetal risks associated with obesity. Midwives will encourage you to be physically active and will provide information and support on dietary intake (eat well plate, portion frequency and size).
Pregnancy is not a time to diet but is a time to avoid excessive weight gain. It is not necessary to eat for two. Only 200 calories extra per day are required in the last three months of pregnancy.
