Research to Reader: fertility science
Body Mass Index or BMI can be used to provide a general indication of whether you are underweight, normal weight or overweight. Your height and weight are used to calculate your BMI. Determine your own BMI - click here for a link to an online BMI calculator.
Your body mass is made up of fat, lean mass which includes muscle, and bone. In most cases the component contributing to a high BMI comes from fat rather than muscle. A healthy BMI range for fertility is 20-25. Fertility studies have investigated BMI and outcomes for spontaneous conception and assisted reproductive treatments.
Studies have shown a raised BMI is associated with a high risk of reproductive complications in women such as menstrual dysfunction, lack of ovulation, infertility and lower conception rates. In males there is also a relationship between BMI and sperm quality, with increases in BMI (above 25+) associated with reduced sperm count, sperm concentration and semen volume.
Low levels of body fat, indicated by a low BMI (under 20) can also affect fertility and these can be addressed through the right exercise and energy balance.
The good news is that physical activity and diet can improve male factor fertility and the chance of conception in females. Women with a high BMI (30+) that undertake regular exercise and eat healthy before IVF and ICSI have a 3 fold higher chance of getting pregnant and having a baby than those who do not. A 300% increase- that is absolutely HUGE! This increase in chance of pregnancy is realised even without a significant reduction in body weight. That means that no matter what your BMI is - combined exercise and diet will improve your chances!
Your exercise program and nutrition guidance are tailored to your BMI (calculated from your height and body weight). If your BMI is 25 or greater our resource on improving body composition can be found here. If you have a BMI of less than 20 you will find relevant information here.