Our natural fertility is influenced by many factors, some of which are genetically determined, while others may be environmental or related to lifestyle, and thus able to be modified. You will find information below on some of the lifestyle guidelines that can be helpful in optimizing your chances of natural conception or conception during infertility treatment.
Female reproductive function starts to decline many years prior to menopause despite regular menstrual cycles. We are born with a finite number of oocytes (eggs) in our ovaries, and these are depleted with age. Infertility becomes more common after the age of 35. If you are over 35 years old, we recommend seeking help if pregnancy is not achieved after 6 months. Those under 35 years of age may want to speak with a reproductive endocrinologist if they have been trying to become pregnant for one year with no success. There are a number of factors that may increase the risk of losing ovarian function earlier than expected. These include smoking, family history of premature ovarian failure and previous ovarian surgery. The effect of age is not as pronounced in men, but there is an increased risk of certain genetic diseases and possibly autism for children conceived by men over 50 years of age.
Weight can be an important factor in determining one’s fertility. Both extremes, underweight and overweight, may contribute to ovulatory dysfunction and infertility. A body mass index (BMI = weight in kilograms / height in meters squared) of 25-29.9 is considered overweight, while a BMI of 30 and greater is consistent with obesity. A weight loss of only 5-10% body weight may significantly improve ovulation and pregnancy rates. Obesity has been implicated in increased risk of miscarriage and reduced success with fertility treatments.1 Pregnancy risks associated with obesity include an increased risk of high blood pressure, diabetes, birth defects and Cesarean section.2 Obese men have also been shown to have poorer semen quality.3
Excessive coffee consumption has been linked to an increased risk of miscarriage in some studies. As a result, some recommend limiting coffee to 1-2 cups per day.
Smoking has been shown to nearly double the risk of infertility in some studies. The literature is consistent in showing that the prevalence of infertility is higher, pregnancy rates are lower, and that time to conception is increased in smokers compared to nonsmokers. Women who smoke experience menopause 1-4 years earlier than those who don’t. This is thought to be due to the harmful effects cigarette smoke chemicals have on the oocytes, it accelerates their depletion. Smoking is also associated with an increased risk of miscarriage and ectopic pregnancy. Smokers undergoing IVF are approximately 50% less likely than non-smokers to become pregnant. They require higher doses of medication, produce fewer eggs and have more cancelled cycles. Pregnant smokers have a higher risk of low birth weight babies and premature delivery. Smoking has been associated with reductions in sperm concentration (on average 22%), motility and potentially morphology (sperm shape) and function, though evidence linking this to infertility is inconclusive. Smoking may also induce DNA damage in sperm. Due to the risks of second hand smoking to women, men are also advised to abstain.
Alcohol has been linked to hormonal and ovulatory abnormalities. The evidence is inconsistent with respect to the amount of alcohol consumed and its link to infertility. There are other ill health effects of alcohol and hence the recommendation is for <1-2 drinks/day or < 9 drinks/week for women. Male drinking appears to be associated with a reduced chance of pregnancy if consumption exceeds 20 drinks/week. Despite these findings, overall recommendations include limiting drinking to no more than 2 drinks per week for women and 4 for men.
Drugs such as marijuana and cocaine can reduce a man’s fertility. In addition, chemotherapy, metabolic steroids and certain prescription medications can negatively affect fertility for both male & female partners.
Anything that increases the temperature around the testicles or scrotum is thought to affect proper production of sperm. Examples include prolonged saunas or hot baths, cycling, long distance driving, obesity.
It is important to ensure that regular intercourse (2 to 4 times/week on average) is taking place, as prolonged abstinence (less than once per month) may reduce the likelihood of pregnancy by reducing sperm count. In addition, certain vaginal lubricants (those that contain petroleum jelly or Vaseline) should be avoided, as they may be toxic to sperm. A small amount of mineral oil can be used if a lubricant is needed.
A recent study from the Motherisk program at the Hospital for Sick Children has shown that taking a prenatal vitamin significantly reduced the risk of a number of birth defects, and suggests taking a multivitamin containing folic acid for all women of childbearing age. For men, Vitamin C (500mg-1g/day), Vitamin E (400 IU/day) and selenium (200mcg/day) may help improve motility and a multi-vitamin containing zinc (20mg) may help in sperm production. Folic acid (1mg/day) is also recommended. L-Carnitine (1-2 g/day) may be beneficial in some men with sperm motility issues.
Some prescribed medications may be linked to infertility. It is important to discuss all medications, prescription or over the counter, with your physician.
A healthy lifestyle, including regular exercise, stress reduction and a well-balanced diet, along with avoiding smoking and excessive alcohol, will help put you in the best position possible to achieve a healthy and successful pregnancy.
1Oxford Journals, Human Reproduction, Obesity is associated with increased risk of first trimester and recurrent miscarriage: matched case-control study, March 2004
2Mayo Clinic, March 2015
3Spermatogenesis, Impact of obesity on male fertility, sperm function and molecular composition, October 2012
4The Fertility Society of Australia, Pre-conception Health Special Interest Group, Effects of caffeine, alcohol and smoking on fertility