to three per cent of pregnancies. It causes damage to the blood vessels and can affect not only the mother, but also the baby through damage to the placenta and there are some similarities to the underlying disturbance in blood vessels seen in heart disease.
Other studies suggest that women who have had pre-eclampsia and low-birth weight babies (less than 2.5 kg (5 lb 8 oz)) are more likely to develop heart disease in later life than women who do not develop this complication. If these associations are confirmed, then women who experience these pregnancy complications could benefit from screening after pregnancy for risk factors for heart disease and should seek preventive treatment, including lifestyle modifications, such as better diet and increased exercise. Indeed, there is some evidence to suggest that exercise during early pregnancy or before pregnancy can also reduce the likelihood of pregnancy complications like pre-eclampsia. So getting your waistline into shape before pregnancy, with a good diet and regular exercise, might not only be good for your figure but also for the health of you and your baby.
must know
Pregnancy complications that can arise in overweight mothers
• miscarriage
• increased risk of abnormalities in the baby, including neural tube defects like spina bifida and heart abnormalities
• high blood pressure and pre-eclampsia
• thrombosis
• pregnancy-associated diabetes
• slow progress in labour
• increased likelihood of Caesarean delivery
• urinary tract infections
• a large-for-dates baby
• difficulty with delivery because the shoulders are too big
Pregnancy risks for the overweight mother
Your pre-pregnancy weight has the biggest effect on your baby’s birth weight and is a more important factor than weight gain in pregnancy. Women who are very overweight, particularly those with a BMI over 30 when they embark on pregnancy, have an increased risk of problems.
Additional tests for overweight pregnant women
• Your doctor may offer you an additional ultrasound scan at around 18-20 weeks to check for fetal abnormality.
• You may also be checked for pregnancy-induced diabetes. This requires a test in which you take a glucose drink after an overnight fast. Your blood sugar is checked before and after the glucose drink.
• You are also checked regularly for the complications that are more common in overweight mothers, such as pre-eclampsia. Sometimes you will require treatment to prevent a thrombosis from occurring – your doctor will advise you about this.
• Your weight is checked at regular intervals throughout the pregnancy.
Labour and delivery risks
Slow progress in labour is more common if you are very overweight, so you will have a higher chance of having a Caesarean delivery. Emergency Caesarean carries a higher risk of complications than a planned one performed before labour, especially if you are very overweight. Sometimes a planned Caesarean section is considered the least hazardous mode of delivery. The plan for your delivery must be suited to your own
must know
Weight
considerations for assisted conception treatment If a woman is overweight the success of assisted conception is reduced so she should take her BMI into account. This is a very sensible measure for a number of reasons:
• women who are very overweight have reduced fertility
• losing weight can increase fertility
• carrying out assisted conception treatment is technically difficult for women who are very overweight
• the success rate is substantially lower. Women with a BMI greater than 30 have a 30 per cent lower success rate with IVF
particular situation and needs, however, and you should discuss this with your doctor, who is able to give you the specific advice required. If you are having a normal vaginal delivery and the baby is large, the doctors and midwives watch for shoulder dystocia, in which the size of the baby’s shoulders can cause difficulty in delivery.
After delivery, an overweight mother is also likely to need treatment to prevent blood clots, often with injections of heparin under the skin, especially if the baby was delivered by Caesarean section. Women who are overweight are more likely to get infections, such as an infection in their caesarean section wound or a urinary tract infection, which is usually associated with pain on passing urine.
While breastfeeding is being established, it is best to avoid dieting as this can affect your milk production. However, once feeding is established, you can lose up to 2 kg (4½ lb) each month.
Losing weight before pregnancy
Strict dieting to lose a lot of weight is not advisable either when trying to get pregnant or during pregnancy. This is because you may disturb your nutritional balance at crucial stages of your baby’s development. But for women in the overweight and obese BMI ranges, substantial health benefits can be obtained by even modest reductions in weight.
Outside of pregnancy it has been estimated that losing 10 kg (around 22 lb) results in a ten per cent fall in cholesterol, and a significant reduction in blood pressure. In pregnancy, a woman with a BMI in the overweight range above 25 doubles her risk of pre-eclampsia, while if she has a BMI in the obese category (greater than 30), she has at least a three-fold increase in
must know
Take exercise
Exercise plays an important part when trying to lose weight. Your weight depends on the balance between the food you take in and the energy you burn up. If you take in more energy from your food than you burn up with exercise, you will gain weight. If you do not take much regular exercise, build up the amount gradually before you get pregnant.
risk. But perhaps the greatest effect can be seen with the risk of getting gestational diabetes. Compared with a woman with a BMI of 20-25, a woman with a BMI of 26-29 has just over a three-fold increase in the risk of having diabetes in pregnancy, but if her BMI is over 30, the risk is more than 15 times higher. So the risks of many of these complications, including birth defects, is related directly to BMI. The higher the BMI, the higher the risk, so if you have an increased BMI any reduction in weight you can make pre-pregnancy is valuable.
Ideally, specialist advice is required to provide you with an individualized assessment and management plan. Specific help from dietitian and support groups is invaluable in losing weight and maintaining it. It is also valuable to consult your doctor for a full health assessment to help identify any additional or associated problems, like high blood pressure or high blood lipids (fats), which might need specific treatment.
When losing weight, set a realistic target over a period of around three months. Then, in the longer term, to maintain a steady weight and avoid further increases, aim to establish a change in your diet and exercise patterns.
As you correct your weight, you may start to ovulate and so fall pregnant when you were not expecting it. This might be before you and your body are ready for it. Because of this, you might want to consider using contraception until you have reached your target weight.
Weight gain during pregnancy
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Limiting weight gain
Keeping the amount of weight gain in pregnancy low is important