HOW MUCH WEIGHT WILL I GAIN DURING PREGNANCY?

It’s important to remember that a healthy weight gain is good for you and your baby. Your healthcare team will keep an eye on your weight, because gaining too much or too little can affect your health and the health of your baby.

Why you gain weight during pregnancy

While you would expect to gain the weight of your growing baby during pregnancy, it’s worth noting that not all the extra weight is from the baby itself. During pregnancy your body undergoes many changes, both to support the growth of your baby and to prepare you for breastfeeding afterwards.

Here’s an example of the breakdown of weight gain a typical pregnancy might bring.

• Baby (3kg)
• Larger breasts (1kg)
• Placenta (0.7kg)
• Amniotic fluid (0.9kg)
• Larger uterus (0.9kg)
• Increased volume of blood (1.5kg)
• Increased volume of other body fluids (1kg)
• Fat stores (3kg)

These figures will vary between individual women.

Average and recommended weight gain during pregnancy

The average weight gain during pregnancy is between 10 and 12.5 kg (22 to 28 lbs) but it can be more or less than this. Most of the extra weight is put on after the 20^th week and you may even lose weight in early pregnancy due to morning sickness.

Understandably, many women ask how much weight they should put on during pregnancy. However, there isn’t a clear cut answer for this, simply because women vary so much. How much weight gain is best for you may depend on your weight before getting pregnant, with smaller weight gains being better for women who were overweight or obese. Of course, if you’re having twins, or more than two babies, then greater weight gains are expected.

Your BMI will be looked at by your midwife or GP; your BMI or Body Max Index is a medical indication of whether you have a healthy weight at your booking appointment, and it’s based on a calculation that takes your weight and height into account.

Here’s what your BMI score means:

• Less than 18.5 – underweight
• 18.5 to 24.9 – healthy weight
• 25 to 29.9 – overweight
• 30 and above – obese

If you have a normal BMI at booking you will not be weighed regularly, unless there is a concern that you have lost weight or gained excessive weight. If your BMI is above 30, this can increase your chance of complications in pregnancy and birth, so you may be referred to a specialist midwife, dietician or consultant.

If your BMI is less than 18.5, this can also affect your baby and if you have an eating disorder, you may worry about the idea of gaining weight in pregnancy, so talk to your midwife because they will understand and offer you support.

Your midwife will be able to talk to you about the weight gain that is healthiest for you in your particular circumstances.

Gaining too much weight

Gaining too much weight can affect the health of both you and your baby. It can increase your risk of gestational diabetes and pre-eclampsia. It also increases the likelihood of problems during labour, with an increased chance of caesarean delivery and bleeding after delivery (postpartum haemorrhage). Babies born to mothers who have gained too much weight may be very large and are more likely to need admission to the neonatal unit.

Gaining a lot of weight during pregnancy can also make it harder for you to shift the extra weight after your baby is born.

Gaining too little weight

Gaining too little weight can cause health problems for your baby too. If you don’t gain enough weight during pregnancy your baby is more likely to have a low birth weight (less than 2.5kg or 5.5lbs at birth) or to be born prematurely (before 37 weeks).

Managing your weight gain

There’s a lot you can do to help yourself gain a healthy amount of weight during pregnancy. Don’t be tempted to ‘eat for two’; you may be surprised to hear that you don’t actually need to eat much more during pregnancy. In the first six months you don’t need to increase your calories at all, and in the last three months you only need an extra 200 calories a day. That’s about the same as a banana and a piece of toast!

It’s always important to eat a healthy diet, but it’s especially true while you’re pregnant to provide your growing baby with all the nutrients they need. It’s important to keep physically active with activities such as walking and swimming throughout your pregnancy.

Being overweight before pregnancy

If you’re overweight before you get pregnant, don’t try and lose weight by dieting during pregnancy because this may not be safe. However, if you make a few healthy changes to your diet, you may find that you don’t put on any weight and you may even lose a small amount. This isn’t harmful. After you’ve had your baby and finished breastfeeding is the time to think about losing the excess weight, especially if you plan to have another baby in the future.

Getting advice about weight gain

You’ll be weighed at your antenatal booking appointment so if you’re very overweight (more than 100kg), or very underweight (less than 50kg) at the start of your pregnancy you will be given special advice.

If your BMI is normal at your booking appointment you won’t usually be weighed again. If you’re concerned that you’re gaining too much or too little weight, talk to your midwife. They’ll be able to check that all is well, and give you advice and support on how to keep to a healthy weight gain.

We answer your key questions about gaining weight in pregnancy