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Written by Vicky Liu, 4th year Health Sciences co-op student from the University of Waterloo. 

Infertility can be a challenging journey for many individuals and couples hoping to conceive. While the causes of infertility can be complex and multifaceted, understanding the various risk factors is essential for those navigating this challenging path. Although some types of infertility can’t be prevented, addressing the modifiable risk factors can help increase your chances of conceiving and enhance your overall well-being.

1. Diet

Can the food and nutrition choices that women make impact their ability to conceive? A study in 2007 found that following a specific diet, called the "fertility diet," was linked to a lower risk of having trouble getting pregnant due to issues with ovulation. This diet focused on eating less unhealthy fats and animal proteins, and more healthy fats, plant-based proteins, high-fiber carbs, and certain vitamins. Women who followed this diet had a significantly lower risk of fertility problems compared to those who didn't.

The study also looked at factors like weight and exercise, but found that diet seemed to have a bigger impact on fertility.

Some women try taking antioxidant vitamins to improve fertility, but a recent study found that these didn't increase the chances of having a baby compared to not taking them. However, because of differences in how these studies were done, it's hard to draw a definite conclusion, and more research is needed.

When it comes to men's fertility and diet, there's not as much research. Some studies suggest that eating a lot of soy products, which contain compounds called isoflavones, might lower sperm concentration. Antioxidants, which help fight off harmful molecules in the body, have also been studied in men with fertility issues. One big study found that men who took antioxidants had higher rates of live births and pregnancies compared to those who didn't.

2. Caffeine

Many couples attempting to conceive consume caffeine regularly. But it's not clear exactly how caffeine affects fertility. In one study of 104 women trying to get pregnant, those who drank less than one cup of coffee a day were twice as likely to conceive compared to those who drank more. Another study in Europe found that consuming a lot of caffeine, like more than five cups of coffee a day or more than 500 milligrams, was linked to having trouble getting pregnant.

However, a big study in Denmark with over 3,600 women didn't find a strong connection between caffeine and how quickly women got pregnant. Even drinking a fair amount of caffeine didn't seem to make much of a difference. In another study that followed women for 8 years, caffeine intake didn't increase the risk of having trouble ovulating.

For women going through fertility treatments like IVF, caffeine didn't seem to change the overall chances of getting pregnant, but it did affect some aspects of the treatment. More caffeine was linked to fewer eggs being collected during IVF.

It's not clear exactly why caffeine might affect fertility. Some researchers think it might have something to do with how the body handles insulin or glucose, which could impact ovulation. But overall, moderate caffeine intake, like one to two cups of coffee a day, doesn't seem to cause any problems for fertility or pregnancy, according to the American Society for Reproductive Medicine.

3. Alcohol

The link between alcohol and infertility isn't entirely clear yet. While it's well-known that alcohol should be avoided during pregnancy because it can harm the baby, its impact on getting pregnant is still uncertain. Drinking alcohol can temporarily increase estrogen levels, which might interfere with the hormones involved in ovulation, potentially making it harder to conceive. Animal studies also suggest that alcohol could affect the early stages of egg or embryo development, further affecting fertility.

When studying alcohol's effects on fertility, researchers have to consider various factors. For instance, they need to think about who they're comparing drinkers to—are they comparing them to people who used to drink, people who never drank, or people who currently don't drink? Additionally, people's drinking habits can change over time, which might not be captured accurately in studies that only ask about alcohol consumption at one point. Also, studies that rely on people's memories of how much they drank may not always be reliable.

In a study of Danish couples trying to conceive for the first time, the chances of getting pregnant decreased as women's alcohol consumption increased. Similar findings were seen in a Swedish study, where high alcohol consumption was linked to a higher risk of infertility. However, some studies have shown contradictory results. For example, a Danish study suggested that drinking wine might actually shorten the time it takes to conceive.

The effects of alcohol on male fertility are also inconsistent. While heavy drinking has been linked to longer times to pregnancy, other studies haven't found any relationship between alcohol intake and men's ability to conceive. However, when alcohol is combined with tobacco use, it can negatively affect semen quality.

In couples undergoing IVF, the impact of alcohol on pregnancy outcomes varies. One study found that women who drank more alcohol tended to have fewer eggs retrieved during IVF and a slightly lower chance of pregnancy, while another study found that women who drank at least 4 drinks a week had a decreased chance of having a live birth. Couples where both partners drank at least 4 drinks per week also had lower chances of having a baby compared to those who drank less.

4. Tobacco

Frequent cigarette smoking can have a negative impact on fertility and reproductive health. Studies have shown that women who smoke tend to reach menopause 1 to 4 years earlier than non-smokers, which means they stop being able to have children sooner. Additionally, research following women who stopped using birth control found that smokers generally took longer to get pregnant compared to non-smokers. Even after considering other factors like age and alcohol consumption, smokers still experienced significant delays in conceiving. However, quitting smoking can improve fertility rates to levels similar to those who never smoked.

Smoking also affects men's fertility by reducing sperm quality and production. Chemicals from cigarettes have been found in the fluid around women's eggs, which may cause damage and increase oxidative stress. Studies have shown that smoking lowers the success rates of assisted reproductive techniques like IVF, with smokers needing more cycles to conceive and having lower pregnancy and live birth rates.

Additionally, smoking increases the risk of miscarriage in both natural and assisted conception cycles. Although earlier studies suggested that exposure to secondhand smoke didn't affect IVF outcomes, larger studies have shown that it can lead to implantation failure and lower chances of having a baby.

5. Body Mass Index

Both being underweight and overweight can affect fertility and pregnancy outcomes. A study by Rich-Edwards and colleagues found that there's a sweet spot for body weight when it comes to ovulatory infertility—having a body mass index (BMI) below 20 or above 24 kg/m2 increases the risk. They estimated that about 12% of ovulatory infertility in the US is due to being underweight, while 25% is due to being overweight. High or low body weight can lead to issues like irregular periods, not ovulating, and difficulty getting pregnant.

When it comes to men, being overweight can also affect fertility. Studies have shown that men with a higher BMI tend to have lower sperm counts and more abnormal sperm. The hormonal changes that happen with obesity, like higher estrogen and lower testosterone levels, might play a role in this.

Obesity can also make it harder for couples to conceive through techniques like in vitro fertilization (IVF). Women with higher BMIs might need higher doses of fertility drugs during IVF, and they're less likely to have successful pregnancies. Overweight women are also more likely to experience pregnancy complications like preeclampsia and gestational diabetes.

The impact of male obesity on IVF success is still being studied, but some research suggests that it might lower the chances of having a baby, especially with techniques like intracytoplasmic sperm injection (ICSI).

For women with morbid obesity, bariatric surgery—weight loss surgery—could improve fertility by restoring regular ovulation cycles. Some studies have found that women who undergo this surgery are more likely to conceive and have a live birth afterward, especially if they lose a significant amount of weight.

Interestingly, there have been reports of bariatric surgery negatively affecting sperm quality in men, possibly due to nutritional deficiencies or the release of toxins after surgery. However, some men were still able to conceive with the help of IVF despite these issues.

6. Stress and Psychological State

Women who experience high levels of stress might find it harder to get pregnant. Studies have shown that women with higher stress levels have a lower chance of conceiving compared to those with lower stress levels. Additionally, women dealing with infertility often experience higher rates of depression. They tend to have higher depression scores and are more likely to be depressed compared to fertile women.

Researchers have looked into whether stress or psychological factors could be linked to higher infertility rates compared to women who do not have increased stress levels. They've found that certain psychological treatments, like cognitive behavioral therapy or receiving support, can improve the chances of pregnancy for women undergoing infertility treatment.

Some studies have suggested that stress, anxiety, and optimism could affect the success of in vitro fertilization (IVF) treatments. For instance, women who are more optimistic might have a higher chance of having a successful IVF cycle. But other studies haven't found any link between anxiety or stress and IVF outcomes.

Scientists are still trying to understand how stress affects fertility. They've looked at biomarkers like cortisol and α-amylase, which are related to stress responses in the body. Some studies have found that women with higher levels of α-amylase are less likely to conceive, but the evidence isn't conclusive.

7. Exercise

Many women exercise regularly, either to stay healthy, reduce stress from infertility, or manage their weight. But research on how exercise affects fertility is mixed.

A study in Norway found that women who exercised every day were more likely to have fertility problems compared to those who didn't exercise at all. However, those who exercised moderately for 16 to 60 minutes had a lower risk of infertility than those who exercised for less than 15 minutes. Interestingly, women who reported the highest intensity of exercise were more likely to have children over time, suggesting that either they reduced their activity, which improved fertility chances, or that exercise's effects were reversible.

Another study focused on vigorous exercise like running or swimming and found that women with primary infertility (difficulty conceiving their first child) who exercised vigorously for over 60 minutes a day had a higher risk of ovulatory infertility. But a different study suggested that adding just 30 minutes of vigorous physical activity per day might reduce the risk of ovulatory infertility.

When it comes to men, one study didn't find a link between exercise and semen quality. But men who spent a lot of time cycling had lower levels of motile sperm.

For women undergoing in vitro fertilization (IVF), the relationship with exercise is complex. Some research suggests that women who exercise heavily might have a lower chance of a successful live birth after their first IVF cycle, especially if their exercise is cardiovascular.

Overall, while exercise is generally good for health, its impact on fertility and assisted reproductive technologies like IVF is still not fully understood. More research is needed to clarify how different types and amounts of exercise might affect the chances of getting pregnant.

8. Environment

Healthcare providers and the public are becoming more aware of how exposure to harmful environmental substances can affect reproductive health. In 2013, leading medical organizations issued a joint statement highlighting the risks associated with certain environmental toxins and offering suggestions for prevention. These toxins, known as endocrine disrupting chemicals (EDCs), can disrupt hormone production, metabolism, and reproduction. They're present in our environment, food, and everyday products, and exposure to them has been linked to various reproductive disorders. For instance, women with higher levels of perfluorinated chemicals, found in things like animal products, plastics, and carpets, have been reported to have reduced fertility.

Phthalates, commonly found in items like deodorants and food containers, may increase the risk of conditions like endometriosis. Bisphenol A (BPA), often used in plastics, including food containers, has been associated with a higher risk of polycystic ovary syndrome and recurrent pregnancy loss. Even though polychlorinated biphenyls (PCBs) have been banned for decades, they persist in the environment and can be found in the bodies of most Americans, mainly through contaminated foods like fish and dairy products. Studies have shown that higher levels of PCBs in women undergoing IVF are associated with lower odds of having a live birth. However, there are many challenges in studying the link between environmental factors and reproductive health, including accurately measuring exposure, finding suitable comparison groups, and isolating specific factors that might contribute to reproductive issues.

Concluding Thoughts

Although there are several factors that determine treatment success that are beyond a person’s control, it's important to concentrate on improving lifestyle factors that increase fertility or the effectiveness of infertility treatment. Our experienced naturopath, Dr. Wendy, is uniquely equipped to assist in reducing modifiable risk factors and optimizing individuals' chances of conceiving. With her expertise in naturopathic medicine, Dr. Wendy takes a holistic approach to reproductive health, addressing not only the symptoms but also the underlying factors that may affect fertility. She understands the intricate interplay between lifestyle, environmental factors, and reproductive function, allowing her to tailor personalized treatment plans for each individual. Whether it's through dietary adjustments, targeted supplementation, or lifestyle changes, Dr. Wendy empowers her patients to take control of their reproductive health and enhance their fertility potential. To learn more about how you can improve your reproductive health and optimize your chances of conceiving, book a consultation with Dr. Wendy today.


  1. Rossi, B. V., Abusief, M., & Missmer, S. A. (2016). Modifiable Risk Factors and Infertility: What Are the Connections? American Journal of Lifestyle Medicine, 10(4), 220–231.


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