Does Obesity impact my Pregnancy?

Obesity affects an increasing number of men, women and children in western countries, and Australia is no exception. Recent studies suggest over 60% of men, and 50% of women are classified as overweight based on body mass index (BMI). Obesity, often defined as a BMI over 30 has significant implications for pregnancy. A sensible, pro-active and guilt-free approach to addressing the problem can lead to significant short and long term health gains for the individual woman and her unborn baby. 

Why is obesity so common in Australia? 

There are many reasons but genetics, the rise of sedentary lifestyles and occupations, the wide availability of cheap processed high carbohydrate foods, our love of inventing machines to perform manual tasks, and lack of regular exercise are the main factors. 

How is obesity defined? 

The commonest method is based on body mass index (BMI). This formula multiplies your weight in kg divided by the square of your height in meters. Normal BMI range is 20-25. A BMI in excess of 30 is regarded as mild obesity, over 35 as moderate and over 40 as severe. A BMI less than 20 is considered underweight and is associated with its own set of health problems. 

For example: a woman of 1.6m height and weighing 60kg has a BMI of : 60 divided by 2.56 (1.6 x 1.6). This equals approx 23.  

A woman of the same height weighing 80kg will have a BMI of around 31. You can check your BMI on the Heart Foundation BMI Calculator.

Why is it important to manage my obesity in pregnancy? 

There is an increased risk of high blood pressure, gestational diabetes, miscarriage and some abnormalities. Labor sometimes is more difficult leading to a higher emergency Caesarean section rate in line with the severity of obesity. Monitoring the health of the baby can be more challenging for health professionals also: for example Ultrasound imaging is less clear and accuracy can be reduced. 

Recovery from a difficult birth may be more complicated as infection, excessive blood loss and deep vein thrombosis (DVT) rates are higher as BMI increases. 

Recently, research is showing that rates of depression and anxiety are higher also in people battling excessive weight gain. In pregnancy this may increase the chance of the troubling condition of postnatal depression. 

What is a healthy weight gain in pregnancy? 

The general consensus is a weight gain of between 10 and 15kg for the entire pregnancy is reasonable and achievable. Twin pregnancies have an allowance of approximately 20kg. While a high starting weight is one thing, rapid weight gain in pregnancy stresses the body’s metabolism significantly and should be avoided. Know your starting weight before pregnancy and weigh yourself every regularly to keep an eye on weight gain. 

For some people weighing themselves is psychologically challenging and may not be in their best interests. In particular weighing yourself daily is probably a bad idea. 

What can I do about my obesity? 

The first thing is to acknowledge the problem and not run away from it. You are not alone in this, (remember over half of the Australian population is affected by excess weight). There should be no feelings of guilt and your Obstetrician and midwives are there to advise, in a caring, supportive and non-judgmental manner, the ways you may improve your health. 

General dietary assessment is primary with a view to reducing intake of simple carbohydrates critical. A dietitian can be an enormous help and source of encouragement and practical advice. 

Regular meal times and regular sleep times are associated with healthier weight gain. Sleeping in, skipping breakfast and eating a muffin mid-morning (more calories than a Big Mac) is an example of an unhealthy habit. 

Regular exercise helps not only burn calories, but improves mental health and emotional wellbeing, for mums with obesity and pregnancy and also all other patients. This in turn feeds back to healthier eating patterns. Walking as much as possible is simple, requires no skill and is highly effective. Please discuss exercise options with me at any time to see if they are appropriate for you during your pregnancy. 

Most importantly: if you are feeling down and experiencing negative thoughts related to weight, please speak up. It’s always ok to let us know how you feel. Often the answer to improved physical health lies in getting help for anxiety and or depression. Remember, we are here to listen and to help in whatever way we can.   

If you would like to discuss your pregnancy please call for an appointment:

Author: Dr Peter England, Obstetrician and Gynaecologist.
Read more about Dr Peter England

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