Overweight or obese women wanting to start a family are advised to consider their weight before becoming pregnant.
Research focusing on the risks to health of obese mother and their babies has found that overweight women with a body mass index (BMI 25-29.9) and obese women (BMI>30) are a greater risk of developing complications endangering their own health and are also more likely to bear children who are overweight themselves. (Patterson & Jeffs 2012)
Some complications associated with excess maternal body weight
Early nutritional education can help to prevent and manage some of the following complications:
This is characterized by a high blood sugar that starts or is diagnosed during pregnancy. It occurs when the hormones of pregnancy interfere with the normal (blood sugar lowering) action of insulin. Symptoms include blurred vision, fatigue, sugar in the urine and increased thirst. Older women over 25 years are more at risk of gestational diabetes as well as those who have a family history of diabetes or have given birth to infants in the past who have weighed more than 9 kgs.
Toxemia or preeclampsia occurs in pregnancy when the maternal blood pressure is raised and protein is found in the urine after 20 weeks and is detrimental to both mother and child. Symptoms affecting mothers include persistent headaches, swelling of hands, face, feet and ankles, right-sided pain, nausea and vomiting.
Complications with delivery
The provision of epidurals and spinal anaesthetics during labour can be more difficult for overweight and obese women and they are more likely to require caecarians and induced labours than mothers of normal BMI. Obese and overweight woman also experience more wound infections and postpartum haemorrhage and spend up to 1.7 days longer in hospital, than women of normal BMI. Their infants can also be more difficult to deliver with a greater incidence of shoulder dystocia (where the infants shoulder fails to deliver shortly after the head) and macrosomia (“big baby syndrome”).
Stillbirths and Structural abnormalities
The incidence of still birth and structural anomalities increases with maternal weight. However irrespective of weight, women contemplating pregnancy are advised to stop smoking, avoid alcohol and to take folic acid supplements in order to reduce the risk of developing babies that are small for date or affected by fetal alcohol syndrome or neural tube defects.
Diag 1: A comparison of the complications experienced by women of normal and excess body mass index during pregnancy.
|Prevalence in women with a normal BMI (%)||Prevalence in overweight and obese women (%)|
|Stillbirth||0.5 – 0.6||0.6 – 1.9|
|Macrosomia||6.5 – 9.03||12.3 – 13.41|
|Structural anomaly||1.2 – 4.5||2.2 – 5.5|
|Caesarean Section||7.7 – 22.3||10.4 – 32.6|
|Hypertensive disorders (including preeclampsia)||0.7 – 4.8||1.4 – 13.5|
|Gestational diabetes||1.2 – 4.1||3.5 – 9.5|
Recommended weight gains
In 2009 the US Institute of Medicine reviewed the guidelines for weight gain during pregnancy and came up with new recommendations offering a range of weight gains according to maternal BMI.(see diag 2) These guidelines aim to improve the health of both women and children
Diag 2: IOM (2009) recommendations for weight gain during pregnancy
|Total weight gain
Range in kg
|Underweight (<18.5)||12.5 – 18|
|Normal weight (18.5 – 24.9)||11.5 – 16|
|Overweight (25 – 29.9)||7 – 11.5|
|Obese (> 30)||5 – 9|
Nutritional recommendations for a healthy pregnancy
- Try to achieve a healthy body weight before conception. For more information read Lea’s article on nutrition for healthy conception
- Pregnancy is not a time to “eat for two” but rather to concentrate on the quality of foods.
- Use low-fat milk, calcium enriched and milk products
- Avoid foods that are highly processed or contain excessive amounts of saturated fat and salt such as fried foods, crisps, processed meats (sausage and luncheon), cakes and pastries.
- For good bowel health eat plenty of fresh fruit and vegetables, breads and cereals.
- Including fatty fish such as salmon, tuna and sardines in the diet at least three times per week increases the intake of omega 3 fatty acids important for fetal brain and nerve development.
- Exercise regularly for at least 30minutes per day to a level that encourages normal conversation without panting. Learn more by reading Lea’s article on exercise and pregnancy.
- Abstain from smoking and drinking alcohol. For more information read Lea’s article on the effects of early alcohol exposure on children
- Drink plenty of fluids including milk and water
- Vitamin D is available from sunlight as well as foods such as fatty fish (salmon, sardines and tuna) margarine, eggs and red meats. Pregnant women who are Vitamin D deficient require around 1.25mg per month as Cholecalciferol
- Folic acid (or folate) can be found in green leafy vegetables, potatoes, bananas and berries. Pregnant women require around 5mgs of folic acid per day prior to pregnancy and up until the end of their first trimester to assist in the prevention of neural tube defects such as spina bifida.
- Supplemental iron is only prescribed at 28weeks if the maternal iron stores are low. Iron is also available in red meat, egg yolk, dark dried fruit and leafy green vegetables
- Iodine (150mcg/day) is recommended for all pregnant and breast-feeding women.
- Pregnant women require 1200mgs calcium each day which can be achieved by consuming 3 servings of calcium rich foods each day. One serving = 250mls of calcium enriched milk each day, or 2 cheese slices or 150ml pottle of yoghurt.
If you require assistance with weight management prior to conception or during pregnancy then do discuss your concerns with your doctor and contact us for a nutritional assessment.