Approximately 15% of couples experience fertility difficulties. There are numerous factors impacting a person’s fertility. Some of these are out of our control, such as diseases like endometriosis and blocked fallopian tubes, and some we can influence, like lifestyle factors. Lifestyle factors are the modifiable habits and ways of life that can greatly influence overall health and well-being, including fertility.
A woman is born with all the eggs she is going to have in her lifetime. Her eggs age with her, decreasing in quality and quantity. Age is the single most important factor affecting a woman’s fertility.
A woman in her early to mid-20s has a 25–30% chance of getting pregnant every month. Fertility generally starts to reduce when a woman is in her early 30s, and more so after the age of 35. By age 40, the chance of getting pregnant in any monthly cycle is around 5%.
% Chance of pregnancy with age (women)
Though not as marked a decrease as females, male infertility generally starts to reduce around age 40-45 when sperm quality decreases.
In women, the following vitamins and nutrients are linked to positive effects on fertility in women and in semen quality in males:
Conversely, trans fat and “unhealthy diets” (those “rich in red and processed meats, potatoes, sweets, and sweetened beverages”) have negative effects.
Obesity in men has been seen to reduce semen quality, concentration and motility, and, can also be associated with erectile dysfunction.
In women, obesity can cause anovulation (failure to release an egg on any given month). Obese women have also been found to have higher miscarriage rates compared to non-obese women. The good news is that the negative effects of obesity on infertility in women can be reversible with weight loss.
On the flipside, being underweight can also impact fertility in both men and women. Underweight in men can result in lower sperm concentrations, and in women, underweight can cause menstrual irregularities and anovulatory cycles.
For more information, view ‘Weight and reproductive outcomes’ (Your Fertility).
A healthy amount of exercise in men can be beneficial, particularly when combined with a nutritious diet. Studies suggest it can improve both sperm activity and structure.
Similarly, a moderate amount of exercise by women can assist with weight management and subsequent fertility status.
However, there can be too much of a good thing, as excessive exercise, such as with elite athletes, can decrease fertility due to menstrual irregularities. Furthermore, it can impact the success of fertility treatment such as IVF.
These lifestyle habits can have an adverse effect on fertility and pregnancy outcomes.
Caffeine can cause an increased risk of miscarriage. In males, alcohol can cause impotence, and reduced libido and sperm quality. Smoking has been proven to damage eggs and sperm, and cause women to experience early menopause. The good news is that the effects of smoking on eggs and sperm and fertility are reversible. For more information, view ‘Effects of caffeine, alcohol and smoking on reproductive outcomes’ (Your Fertility).
Illicit drugs affect a woman’s fertility in numerous ways.
Cannabis disrupts the menstrual cycle and decreases ovulation.
Stimulants, such as cocaine and crystal meth, cause adverse effects at most levels of the reproductive system and cause a high rate of miscarriages.
Opioids disrupt pituitary and hypothalamus hormone production, causing menstrual irregularities and halting ovulation.
Drug use can also lead to weight loss, poor nutrition, sleep disruption and general physical deconditioning. Each of these side effects can interrupt menstrual cycles and ovulation.
Substance use in males can also impact their fertility as it lowers production of testosterone, which negatively effects sex drive, healthy sperm production and erectile function.