The amount of weight you put on is related to your weight and health before you become pregnant. Even if you know you're already overweight, pregnancy is not the time to go on a diet or try to prevent weight gain. It's best to eat a healthy, balanced diet and take some reasonable exercise.
What's the average weight gain?
Weight gain in pregnancy varies greatly. On average, women at the recommended weight for their height put on between 10-12.5 kg (22-28 lb). If you gain weight within this range, you have a lower risk of complications during labor and birth, and a lower risk of having a baby with a low birth weight (less than 2500 g or 5½ lbs). However, many women who put on weight outside this range go on to have healthy babies.
Putting on too much or too little weight is linked to health problems, which can affect you or your unborn baby.
Gaining too much weight
Gaining too much weight can increase your
blood pressure. It can also increase your risk of complications such as gestational diabetes and pre-eclampsia. These conditions make it more likely that your baby would be delivered by
caesarean section. You are also at increased risk of infections, for example, urinary tract infections.
Gestational diabetes only occurs during pregnancy, and then only if you have too much
glucose (sugar) in your
blood. It usually disappears after your baby is born.
Pre-eclampsia occurs during pregnancy or immediately after your baby is born. Pre-eclampsia is usually mild and does not always need treatment. However, it should always be taken seriously because, in a few cases, it can cause complications, such as growth problems in the baby.
Throughout your pregnancy, you will have regular check-ups to try to identify any 'hidden' health problems. The conditions and infections that health professionals look for include urinary tract infections, anemia, diabetes,
high blood pressure, Hepatitis B, syphilis and HIV.
Gaining too little weight
Gaining too little weight can cause problems such as premature birth and a baby with a low birth weight. It can also mean that your body is not storing enough fat.
However, women who are naturally very slim with a high metabolic rate can go on to have babies with a healthy birth weight. (Your metabolic rate is the amount of energy your body uses when you're resting.)
Lack of weight gain can be related to your diet and weight over previous years. It can also be caused by your body not absorbing food properly, which increases your risk of anemia.
Your ability to absorb food effectively may be affected if you have an eating disorder, such as anorexia nervosa or bulimia.
Your doctor will try to identify any complications through your regular check-ups. Your doctor can also give you advice about healthy eating and exercise during pregnancy.
When will I put most weight on?
Usually, you put most weight on after week 20 of your pregnancy, although this too depends on your weight before you're pregnant. Much of the extra weight is due to the growth of your baby, but your body will also be storing fat ready to make breast milk after the birth. Breast milk is 98% fatty acids, which play a key part in the newborn baby's early development.
Regardless of how you're planning to feed your baby, putting on weight is a very important part of your pregnancy.
Eating healthily is important both for you and your unborn baby. Try to focus on the quality of what you eat rather than how much - you don't need to 'eat for two'. You need around 300 more calories a day.
You should eat from these food groups each day:
- 4 to 6 portions daily of carbohydrates such as rice, pasta, cereals, bread and potatoes,
- at least 5 portions of fruit and vegetables each day,
- 3 daily portions of protein - choose from meat, poultry, fish, legumes or eggs, and
- at least one portion a day of dairy products like milk, cheese and yogurt.
Foods rich in iron and folate are recommended, such as green leafy vegetables and meat.
It's also important to keep fit and healthy. Staying active through exercise can help, unless you've been advised by your midwife or doctor not to exercise. It also means your body may be more prepared for the physical demands of labor, birth and the early days with your newborn baby.
If you weigh less than 50 kg (8 stone) or more than 100 kg (15½ stone), your midwife or doctor may have special advice for you.
If you're concerned about your weight or any other aspect of your health, always ask your midwife or doctor for advice.