Obesity and Fertility

Obesity and Fertility

• Introduction to obesity
• Introduction to fertility
• How is obesity related to fertility?
  • Male obesity and fertility
  • Female obesity and fertility
  • Leptin – a link between obesity and fertility
• Psychological factors
• How does treating obesity affect fertility?

Obesity may be defined as a body mass index (BMI) of 30 or higher. It is a medical condition in which excess body fat builds up to the extent that the health of the individual becomes negatively affected. It is becoming increasingly common in both men and women in Western developed nations, including Australia and the US, and exerts significant financial pressure on health care systems.

Obesity is usually not caused by a single factor, although the genetic make-up of a person can influence the probability of developing the condition. The most significant contribution to the rise in obesity is thought to be the changes in behaviour and environment seen in modern society as a result of technological advances. In particular, the reduction in physical activity levels has been put forward as a major contributing factor in the development of the disease.

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The formula for calculating your body mass index is:
BMI = weight (kilograms) / (height (metres) * height (metres))

For example:
A man who weighs 85 kilograms and is 1.8 metres tall would have a BMI of
BMI = 85 / (1.8 * 1.8)
BMI = 85 / 3.24
BMI = 26.2

This information will be collected for educational purposes, however it will remain anonymous.

Many health conditions are associated with obesity. Well-known conditions include type 2 diabetes, coronary heart disease and sleep apnoea. However, obesity can also affect the fertility of both men and women by contributing to problems with ovulation and general sexual dysfunction. These are discussed later in this article.  

smoking can adversely affect fertility in males and females. Health issues such as weight and fat distribution of an individual can also impact on fertility.    

oestrogen levels, with increased fat deposits corresponding to higher oestrogen and lower testosterone levels. These elevated oestrogen levels in men tend to suppress fertility because they prevent the synthesis of androgens (hormones required for the development and maintenance of normal male reproductive function). In addition, metabolic syndrome, a condition that can arise from obesity, is also associated with symptoms of erectile dysfunction, hence compounding the adverse effects obesity has on fertility.

amenorrhoea.

Obesity is also often associated with increased insulin production and insulin resistance. These two factors are believed to contribute to hyperandrogenism in obesity because insulin is important for the regulation of sex hormone production. This can be seen in obese women with PCOS, where excess weight gain leads to excessive insulin production, promoting increased androgen secretion and abnormal follicles in the ovary. This results in an overall disruption in ovarian and menstrual activity, causing fertility problems.

Obese women who turn to assisted reproductive technologies (ART) also face additional obstacles compared to non-obese patients. Obesity is linked to decreased success of fertility treatments such as in vitro fertilisation (IVF).

central nervous system (CNS). When fat stores and hence leptin levels are high, the brain acts to decrease food intake and to increase energy expenditure. Studies have found that laboratory mice without circulating leptin develop both obesity and infertility, and that administration of leptin later on leads to the restoration of normal body weight and fertility. Leptin therefore plays an important role in the relationship between obesity and fertility.

Although leptin is present in large amounts in obesity, excessive fatty tissue is maintained, along with a decrease in fertility. It is believed that obese individuals have some sort of resistance to leptin that cannot be overcome by high leptin levels, making it difficult for obese individuals to lose weight.

sexuality, which impacts on their overall fertility.

How does treating obesity affect fertility?

Virtual Medical Centre Video

Click here to watch a video on possible treatments for obesity.

Weight loss can dramatically improve fertility in obese people. It is often the first step in fertility treatment when an obese patient seeks help from assisted reproductive technology (ART). Even a loss of 5-10% can significantly improve ovulation and pregnancy rates.

Weight loss improves fertility in obese people both physiologically and psychologically. Psychological state and mood has been found to increase significantly after weight loss, and a reduction in insulin and androgen levels has been found in women. This may lead to an 80% improvement in menstrual function and pregnancy rates of 29%.

More information 

For more information on obesity, health and social issues, and methods of weight loss, as well as some useful tools, see Obesity and Weight Loss.

For more information on living with obesity, including discussing obesity with friends or loved ones, bullying and obesity in children, obesity and its cost on the workplace and links between obesity and pain, sexuality and depression, see Living with Obesity.

 

Reference

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Article Dates:

Modified: 27/1/2011

Created: 10/6/2008


Obesity and Fertility