Maintaining a healthy weight, diet and exercise during pregnancy

Eating a healthy diet and being physically active are especially important in pregnancy as your unborn baby has to get everything it needs to grow and develop from its mother.

If your weight is higher or lower than the healthy range when you become pregnant, it can affect your pregnancy as well as your general health.

What is a healthy weight?

We use your height and weight to work out your body mass index (BMI).

• BMI Healthy range 18.5 to 25
• Underweight less than 18.5
• Overweight 25 to 30
• Obese 30 and above

During pregnancy there is a greater chance of certain problems if a woman’s BMI is less than 18 or more than 30.

Weight gain in pregnancy

It is important to accept that you are going to become bigger during pregnancy.

The normal changes in the body during pregnancy and the growing baby can add up to an average weight gain of around 11 kg (24 lb). Some of this is fluid, breast tissue and a small store of fat for breastfeeding.

The following table shows the recommended weight gain for the whole pregnancy based on your BMI at the start. You should expect most of the weight gain to happen after the 20th week of pregnancy

BMI at beginning of pregnancy Recommended total weight gain.

• 18 or less 12.5 – 18 kg (28 – 40 lbs)
• 19 – 25 11.5 – 16 kg (26 – 36 lbs)
• 26 – 29 7.0 – 11.5 kg (15 – 25 lbs)
• 30 or more 7.0 kg (15 lbs)

The more weight you put on above the recommended amount in pregnancy, the more weight you will be left carrying after the birth of the baby.

There is no need to ‘eat for two’ during pregnancy. In fact, your body becomes more efficient and you only need an extra 200 calories per day in the last three months (equivalent to a small sandwich or a pot of yoghurt and a banana).

Do not try to diet to lose weight during pregnancy, but try to eat healthily and be as active as you can.

It is important to take Folic acid (400 micrograms per day) until the 13th week of pregnancy, in order to reduce the risk of some birth defects. If you have a BMI above 30, you will need a higher dose of 5 mg. Your midwife will arrange for your GP to prescribe this.

It is also important to take Vitamin D (10 micrograms daily) during pregnancy and whilst you are breastfeeding to maintain healthy bones.

Your midwife can give you more information about how to have a healthy diet and exercise safely in pregnancy. There is a helpful section on the NHS Choices website (www.nhs.uk) on eating well for pregnancy.

What are the problems with being underweight in pregnancy?

If you have a low BMI in pregnancy you have an increased chance of the following problems:

• Having a low birth weight (small) baby
• Premature birth
• Anaemia (low amount of iron in the blood)

What are the problems with being very overweight in pregnancy?

If you have a high BMI in pregnancy (especially if it is higher than 30), you have an increased chance of the following problems:

• Increased risk of miscarriage and stillbirth
• Difficulties for us seeing your baby at ultrasound, therefore making it more difficult to screen your baby for birth defects and measuring its growth
• High blood pressure
• Pre-eclampsia
• Diabetes (some women can become diabetic just during pregnancy)
• Having a big baby, which increases the risk of being overweight as a child and an adult
• Blood clots in the legs or lungs (especially in the few weeks after the birth)
• Having a baby that has a birth defect
• Going into labour before 37 weeks gestation

What are the problems with being overweight in labour and after having your baby?

If you have a high BMI in pregnancy (especially if it is higher than 30), you have an increased chance of the following problems.

• A long labour
• Caesarean Section
• Anaesthetic complications
• Bleeding heavily following the birth of your baby
• Blood clots in the lungs and legs
• Wound infection
• Difficulties with breastfeeding

When you see a midwife or doctor during the pregnancy, they will be checking you and the baby to try to detect whether any of these complication are developing. If you are worried, speak to the midwife or doctor and they will be able to explain things in more detail.

Our plan for your care

If your BMI is 18 or less, or your BMI is 35 or more, or less if you have pre- existing medical conditions:

• You will be booked for your care with a doctor at the hospital because of the increased chance of certain complications.
• You will not need to come to the hospital every time but may have many of your appointments locally with your community midwife.

Your midwife will monitor your weight during your pregnancy. She can help you to manage your weight safely. If you would like to discuss your diet in more detail, please ask to have an appointment to see a dietician.

Exercise in pregnancy

It is important to be as active as possible during pregnancy. You can exercise safely without risk to you or your baby. Gentle regular exercise, such as swimming, yoga and walking, can improve muscle tone and strength and can also relieve tiredness, lower back pain and reduce varicose veins, swollen ankles and constipation.

Aim for around 30 minutes a day. The idea is to maintain your fitness levels, rather than become super-fit.

During pregnancy you should avoid contact sports where there is a risk of being hit in the abdomen, such as kick-boxing, martial arts or squash. If you are uncertain about what exercise is safe for you and your baby, please discuss this with your doctor or midwife.

There is a helpful information leaflet about exercise in pregnancy on the ‘Information for patients’ section on the Royal College of Obstetricians and Gynecologists’ website (www.rcog.org.uk).

After the baby is born

It is important to try to breastfeed for your own and your baby’s health.  If you are having difficulties, please speak to your midwife for advice.

After the pregnancy it is important to return to a healthy weight. Losing weight gradually will not affect the quality or amount of breast milk you produce.

You can get help and advice about losing weight and healthy eating from your Health Visitor, GP or practice nurse.

You can reduce the chance of problems in future pregnancies by trying to get your weight into the healthy range before you try for another baby.

Being a healthy weight will also help your chances of conceiving in the future.

Pregnancy is a great time for learning about healthy eating and physical activity. One of the most important things we can do for our children is to give them a Healthy Start in life.

Healthy eating, drinking and exercise

Make sure that you eat a variety of different foods to get the right balance of nutrients for your growing baby and for your body to deal with the changes taking place.  It is important to prepare and cook your food carefully to prevent food poisoning. Drinking plenty of fluids is also important to avoid dehydration, your body is working harder than usual and will need extra fluid intake. It is normal to gain weight in pregnancy due to the normal changes in your body and the growing baby.  The more weight you put on above the recommended amount of 11kg, the more weight you will be left carrying after the birth of your baby. 

To be avoided in Pregnancy
Foods such as ready meals, meat, poultry, shellfish and eggs need to be thoroughly cooked.  Avoid pate and mould-ripened soft cheeses: liver and liver products and unpasteurised milk.  Have no more than two portions of oily fish a week and avoid marlin, swordfish and shark.

Caffeine – is a stimulant that is contained in tea, coffee and cola drinks and too much caffeine should be avoided as it is passed through the placenta and may affect your baby.

Alcohol – increases the risk of miscarriage or may lead to Fetal Alcohol Spectrum which results in behavioral problems to severe abnormalities.  Pregnant women are advised not to have any alcohol, at any stage of their pregnancy.

Drugs – taking any “street” drugs should be avoided at all times during pregnancy as it may seriously harm you and your baby.  Avoid, unless prescribed by a Doctor, any analgesic (pain killers) containing Aspirin.

Smoking – If you smoke tobacco, carbon monoxide, nicotine and other toxic chemicals cross the placenta directly into the baby’s bloodstream, so the baby smokes with you.  This will reduce its oxygen and nourishment, and put it at risk of miscarriage, stillbirth, low birth weight, premature birth and other problems.  The sooner you stop smoking the better.  Passive smoking is also damaging to you and your baby.  Ask at your GP surgery if there is a smoking cessation coordinator to help you and family members to stop smoking or contact the NHS Pregnancy Smoking Helpline 0800 1699169.

Supplements
It is advised that you take supplements of Folic Acid which helps to prevent abnormalities in the baby (spina bifida).  The recommended dose is 0.4mg per day for at least eight weeks before becoming pregnant and then for 12 weeks into the pregnancy.  If you have diabetes or are taking anti-epileptic drugs or have a family history of fetal anomalies the recommended dose is 5mg per day.  The NHS website provides information on vitamins and supplements.

Vitamin D is needed for healthy bone development.  To protect your baby and yourself from the problems caused by low levels, a 10mcgs Vitamin D supplement is recommended as found in the Healthy Start Vitamins.

Vitamin A supplements should NOT be taken in pregnancy and any other supplements should only be taken after checking with your midwife. 

Peanuts
If you would like to eat peanuts or food containing peanuts (such as peanut butter) during pregnancy, you can choose to do so as part of a healthy balanced diet, unless you are allergic to them or your health professional advises you not to.

You may have heard that some women have, in the past, chosen not to eat peanuts when they were pregnant.  This is because the government previously advised women that they may wish to avoid eating peanuts if there was a history of allergy (such as asthma, eczema, hay fever, food allergy or other types of allergy) in their child's immediate family.

This advice has now been changed because the latest research has shown that there is no clear evidence to say if eating or not eating peanuts during pregnancy affects the chances of your baby developing a peanut allergy.

Nausea
It is not unusual to experience loss of appetite and sickness in the early stages of pregnancy.  If you suffer from sickness, it may helpful if you:
• Keep your meals small, light and regular;
• Avoid fried, rich and highly spiced food:
• Have a hot drink and biscuit before going to sleep.

Constipation
This is often a side effect of pregnancy.  If you have a tendency to become constipated, increase the amount of fibre in your diet and drink plenty of fluid.  Choose wholemeal bread and eat a high fibre breakfast cereal.  Eat plenty of fruit and vegetables (beans and peas are rich in fibre).  Try brown rice and wholemeal pasta and use wholemeal flour in cooking.

Heartburn
Small frequent meals and avoidance of fried, fatty and spicy foods may help.

Exercise
Regular exercise during pregnancy is extremely important.  Contact sports and scuba diving should be avoided.  If you do not currently exercise then you need to commence by going swimming; going to aqua natal classes, cycling or attending recognised exercise classes but do inform the instructor that you are pregnant.

Your midwife will monitor your weight during your pregnancy.  She can help you to manage your weight safely.  If you would like to discuss your diet in more detail, please ask to have an appointment to see a dietician.