14 Unexpected Factors Leading to Infertility

Besides aging, there are manageable factors affecting the fertility of men and women

Around 10-15% of couples impacted by infertility.

The unstoppable biological clock, aging, provides a timeline on the fertility of men and women.  Click here to find out how aging affects female reproductivity.  In addition, other factors can play a significant role in rendering infertility to men and women.  A piece of rather promising news is that these factors can be managed to improve fertility during the fertile stage in life.


The main factors affects fertility in men and women, including the lifestyle factors that can be modified and controlled, are summarized as below to encourage reader’s awareness and early invention if applicable [1]:




Psychological Effect (Stress, Depression)

Cigarette Smoking



Air Pollution, Heavy Metals

Pesticides, Endocrine Disruptors, and other Chemicals



Radiation (Cell Phone)

Tight-fitting Underwear






1. Nutrition

Men’s sperm quality and women’s ovulatory function can be improved by focusing on consuming certain nutrition while avoiding some others. Here are few suggestions;

For men

Following a diet that contains an abundant amount of carbohydrates, fiber, and folate has proven beneficial for semen health. Avoid high amounts of protein and fats, accompany more fruits into your meals. Adding vitamin C supplements to your daily food intake had been proven beneficial. 

For women

Focus on the food that contains more plant proteins than Carbohydrates. Usage of transfats is considered to be harmful so better opt for monounsaturated fats. Other food suggestions include food rich in antioxidants, omega 3 fatty acids, Avocado, fish, and high fats dairy. Eat a bigger breakfast, and cut down your evening meals.

2. Weight

For men – overweight

  • Obese men are 3 times more likely to exhibit a reduction in semen quality than normal-weight men.
  • An increase in BMI is correlated with a decrease in sperm concentration, a decrease in motility, and erectile dysfunction (96.5%), causing infertility.
  • Overweight men have also been found to have increased DNA damage in sperm.
  • A study done in china concluded as, being overweight was significantly associated with lower semen volume, total sperm number, and total motile sperm count.

For women – overweight

  • Women with BMI above 30 take-ups longer time pregnancy than women with BMI between 20 and 25.
  • The miscarriage rate is 13.6% of obese women comparing to 10.7% of a normal BMI.
  • Higher rate of recurrent, early miscarriage that may not be due to the chromosome abnormalities/karyotype of the developing fetus.
  • After losing an average of 10.2 kg, 90% of obese and previously anovulatory women began ovulating.

For men – underweight

  • Lower sperm concentrations. It had already been considered controversial but in a recent study in 2019, lower sperm concentrations, the total number of sperm, and total motility of sperm were affected by being underweight. while overweight was significantly associated with lower semen volume, total sperm number, and total motile sperm count.

For women – underweight

  • Ovarian dysfunction and infertility; the risk increases for women of BMI below 17.
  • Underweight women have an increased risk of pre-term birth.
  • Women with eating disorders can have menstrual irregularities and are at a higher risk of infertility.

Click to find out how you can control your weight and be fit.

3. Exercise

For men

Be moderately active – between 180 minutes and 300 minutes per week.

For women

Be moderately active – less than 240 minutes of cardiovascular exercise per week.

  • Women who engaged in cardiovascular exercise for 4 hours or more per week had a 40% decrease in live birth rate, higher risks of cycle cancellation and implantation failure in a study of women undergoing in vitro fertilization (IVF).
  • Women who engage in rigorous physical exercise may be at risk of infertility due to anovulation and implantation defect.

Click here to find out what exercises to do for your stage in life.

4. Psychological Effect / Stress

For men

Positive and happier men with stress-free and depression-free increase sperm quality.

For women

Work less than 32 hours a week and keep a positive and stress-free, and depression-free mood to improve reproductivity.

  • Women who had a job and worked over 32 hours a week experienced a longer time to conceive than women who worked 16 to 32 hours a week.
  • 30% of women who seek infertility treatments are due to psychological stress, including anxiety and depression.
  • Women who receive support and counseling may reduce their anxiety and depression levels increasing the chance of pregnancy (54-55%)
  • Fertilization of oocytes also decreased when stress increased.

5. Cigarette Smoking

For men

Smoking affects all sperm parameters.

For women

Smokers are less fertile and take a longer time to conceive.

Click here to find out why smoking makes women single.

6. Drugs

For men

Drugs reduce sperm parameters and sexual functions.

  • Marijuana negatively affects sperm parameters in motility, capacitation, acrosome reaction.
  • Cocaine can decrease sexual stimulation – men found it harder to erect and ejaculate. It also affects spermatogenesis.
  • Opiates, methadone, and heroin can render sexual dysfunction and decrease sperm parameters, especially in motility.

In a study, 93% of males who stopped or switched the medication improved 93% on semen quality, and 85% conceived within 64 months. The control group improved by 12% in semen quality, and only 10% conceived within the same period.

Most studies showed that prescription drugs caused impaired spermatogenesis, sperm motility, and erectile function for men.  The study also showed that non-steroidal anti-inflammatory drugs, Cox-2 inhibitors, impaired follicle rupture, ovulation, and tubal function and that antihypertensives caused fertilization failure for women.

For women

Women are more prone to be affected by drug abuse than men, according to (Center for Behavioral Health Statistics and Quality 2017. Illicit drugs can cause render irregularity of hormones and stillbirth.

  • Marijuana adversely affects hormonal regulation and can cause oviducts, placental and fetal development, and stillbirth.
  • Heroin and methadone are known to cause amenorrhea.
  • Cocaine, opiates can cause placental abruption.

7. Prescription Drugs

  • Antibiotics,
  • antidepressants,
  • antiepileptics,
  • b stimulators,
  • H1 and H2 receptor antagonists,
  • mast cell blockers and
  • sulfonylurea compounds etc.

8. Alcohol

For men

  • Alcohol consumption has been linked with negative side effects such as testicular atrophy, decreased libido, decreased sperm count, semen volume, sperm morphology.

For women

  • Women who experienced hangovers were more likely to be infertile than women who did not experience hangovers.
  • Women who drink large amounts of alcohol have a higher chance of experiencing an infertility examination than moderate drinkers.
  • An evidence-based study had shown negative effects on IVF treatment on women who wanted to conceive. 13% decrease in the numbers of oocytes retrieved, a 2.86 times likelihood of not achieving pregnancy, and 2.21 times higher risk of abortion among women who consume alcohol than controls.

9. Caffeine

Caffeine has more than 100 elements in it and a few of them do affect fertility. Caffeine has been reported to have negative effects on female fertility during pregnancy.

For men

Caffeine-containing energy drinks had been proven to be bad for the human body. They readily pass through the biological membranes of the body and may also disturb male gonadal development.

For women

  • Women who drink over 500mg of caffeine per day are linked to increasing time to pregnancy of over 9.5 months.
  • Women who consumed more than 100mg of caffeine per day were likely to experience a miscarriage or spontaneous abortion even of normal karyotypes.
    • Consumption of 145mg of caffeine per day has a higher chance of having stillbirth or miscarriage in the first trimester.
  • Regarding chance of stillbirth:
    • 4 to 7 cups of coffee per day had a nearly 80% increase
    • more than 8 cups per day had almost a 300% increase in chance along with the risk of fetal death.
    • Mothers to be are advised to avoid caffeine intake, according to research carried in 2020.

Here below is a table that gives an idea about the level of caffeine; in addition, a guideline of 80 mg of caffeine for each 10 g of dry coffee is given on this website. https://coffee.stackexchange.com/questions/79/how-can-i-figure-out-how-much-caffeine-is-in-my-cup

Description Serving Size Caffeine (mg)
Starbucks Coffee, Blonde Roast venti, 20 oz. 475
Starbucks Caffè Americano grande, 16 oz. 225
Starbucks—Caffè Latte or Cappuccino grande, 16 oz. 150
Starbucks Espresso doppio, 2 oz. 150
Nespresso capsule—except Kazaar 1 capsule, makes 1 oz. 50-80
Starbucks Chai Latte—iced or regular grande, 16 oz. 95
Black tea, brewed 8 oz. 47
Snapple Lemon Tea 16 oz. 37
Green tea, brewed 8 oz. 29
Lipton Lemon Iced Tea 20 oz. 25
Herbal tea, brewed 8 oz. 0
Soft Drinks    
Red Bull 8 oz. 80
Diet Coke 20 oz. 76
Coca-Cola, Coke Zero, or Diet Pepsi 12 oz. 34
7-Up, Fanta, Fresca, ginger ale, or Sprite 12 oz. 0
Dr. Pepper or Sunkist—diet or regular 12 oz. 41
Ice Creams & Chocolate    
Häagen-Dazs Coffee Ice Cream 4 oz. 29
Dannon Coffee Yogurt 1 container, 6 oz. 30
Starbucks Hot Chocolate grande, 16 oz. 25
Hershey’s Milk Chocolate Kisses 9 pieces, 1.4 oz. 9

Click here to find out how you can choose your food to optimize your health.

10. Air Pollution

Air pollution has received much attention in the past few decades for fertility-based causes. It releases pollutants including sulfur dioxides, carbon monoxide, nitrogen dioxide, particulate matter, and ozone into the atmosphere from motor vehicle exhaust, industrial emissions, the burning of coal and wood, and other sources. 

For men

  • Several studies have been conducted in the Czech Republic regarding this and it resulted as, Men exposed to higher levels of air pollution were more likely to experience abnormal sperm morphology, decreased motility, and an increased chance of DNA fragmentation.
  • A negative correlation is found between sperm concentration and the amount of ozone to which a man was exposed.

For women

11. Heavy Metals

Heavy metals include lead, mercury, boron, aluminum, cadmium, arsenic, antimony, cobalt, and lithium.  Few studies have been conducted on heavy metals and reproductive functions; nonetheless, the below effects have been identified.

  • Lead is commonly found in batteries, metal products, paints, ceramics, and pipes.
  • Mercury is often found in thermometers, batteries, and industrial emissions, and tainted seafood.
  • Boron is used in the manufacturing of glass, cement, soap, carpet, and leather.
  • Cadmium can cause testicular necrosis, lower libido, and infertility. 

For men

  • Lead and boron alter sperm quality
  • Mercury affects spermatogenesis.
  • Cadmium can cause testicular necrosis, lower libido, and infertility.

For women

  • Lead can cause irregular menstruation, preterm delivery, miscarriage, stillbirth, and spontaneous abortion.
  • Mercury can disrupt fetal development.

12. Pesticides, Endocrine Disruptors, and Other Chemicals

Infertility can be the result of overexposure to certain chemicals and endocrine disruptors, which have proven adverse effects on the reproductive health of men and women:

Chemical Possible Reproductive Effects
  For Men For Women
BPA Inhibits binding to the androgen receptor,

decreased semen quality,

erectile dysfunction,

chromosomal abnormalities in the oocyte,

recurrent miscarriage,

Disinfection by-Products
Organochemicals and Pesticides

e.g., DDT, DDE, Methoxychlor

decreased semen quality,

chromosomal abnormalities in sperm,

altered histology of testes,

decreased libido,

Change in hormone levels,

irregular menstruation,

decreased fertility,

fetal loss,


Dioxins Changes in hormone levels,

altered puberty,

altered start of menarche,

endometriosis, decreased fertility,

fetal loss

Phthalates Decreased semen quality,


earlier menarche,

altered menstrual cycle,


Solvents Change in hormone levels,

decreased semen quality,

irregular menstruation,

decreased fertility, miscarriage,

fetal loss

Alt tag: Chemicals and their respective effects on both male and female reproductive function

The powerful negative effects of these chemicals make people who are often exposed to them vulnerable to an increased risk of reproductive health.  This includes gardeners, jewelry-making, painters, manipulators of ceramics, and stained glass.

For men

  • Men who work in agricultural regions and greenhouses that use pesticides have higher concentrations of common pesticides in their urine, reducing semen parameters, oligozoospermia, lower sperm counts, and decreased sperm concentrations by 60%.
  • Workers of factories that produce batteries rendering a high exposure to lead may have reproductive incapabilities, including asthenospermia and teratozoospermia.

For women

  • The female partner of men who work around pesticides would have decreased implantation rates.

13. Radiation

Radiation in the form of x-rays and gamma rays can be devastating to the sensitive cells of the human body, depending on the age of the person and dose, and it can ultimately result in permanent sterility.

The radiofrequency electromagnetic waves (RFEMW) of cellular phones have negative effects on fertility amongst men.

For men

  • Cell phone usage has been linked with decreased sperm motility, sperm counts, sperm viability, increase in reactive oxidating species, and abnormal sperm morphology.
  • Men who carry their cell phones around the beltline or hip region were more likely to have decreased sperm motility.

14. Others

For men

  • Medical treatments such as chemotherapy and radiotherapy can impact the ovarian reserve and resulting infertility for women and men.
  • Tight-fitting underwear worn by men can temporarily decrease sperm parameters by 50% and the risk of impaired semen quality by 2.5 versus loose-fitting underwear.
  • Certain lubricants can render a negative impact on sperm motility and sperm chromatin damage.


Through a better understanding of various factors leading to infertility, one can learn to modify the habits and lifestyle as early as possible to optimize fertility potential, avoiding the frustrations and psychological pains due to the preventable reproductive challenges.

Age: The peak of fertility for men is reported as 35, and for women is 30 years. Younger couples are encouraged to seek medical care if not able to conceive in one year.

Smoking:  It should be avoided at all costs either passive or active smoking. If you wish to have babies. It will help to delay menopause for 4 years and miscarriage can be avoided.

Stay Healthy: Maintaining a good weight and BMI is beneficial for fertility and helps to avoid miscarriages.

Alcohol and Caffeine: It is advisable to abstain from alcohol if would wish to become a parent in the future. Also, intake of caffeine must be limited as per the guidelines given above.

Manage Stress: Infertile couples are recommended to avoid stressful and anxiety-filled situations. A couple of relaxation exercises can prove beneficial.

Nutrition and Exercise: As already told above, a moderate diet for women and men is suggested by professionals. Infertile women should consume foods low in saturated fat, red meat, and high in vegetables, legumes, and antioxidants.

IVF: Meanwhile, there is an increasing trend of delaying motherhood – has the female body evolved accordingly along with this trend?  To deal with this phenomenon, women resort to preserving the quality of oocytes using oocyte cryopreservation / egg-freezing.

Click here to find out the egg-freezing process and see if you or your nulliparous friends should consider it as a way of preserving fertility.


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[2]   National Research Council (US) Panel on Understanding Divergent Trends in Longevity in High-Income Countries, «Explaining Divergent Levels of Longevity in High-Income Countries,» 2011. [Online]. Available: https://www.ncbi.nlm.nih.gov/books/NBK62373/.

[3]   «World Health Statistics 2016: Monitoring health for the SDGs,» 2016. [Online]. Available: http://www.who.int/gho/publications/world_health_statistics/2016/Annex_B/en/.

[4]   T. Mathews e B. Hamilton, «Mean Age of Mothers is on the Rise: the United States, 2000–2014,» Centers for Disease Control and Prevention, January 2016. [Online]. Available: https://www.cdc.gov/nchs/data/databriefs/db232.pdf.

[5]   H. J. Jung e M. W. Byung, «Theoretical estimation of maximum human lifespan,» 17 June 2008. [Online]. Available: https://link.springer.com/article/10.1007%2Fs10522-008-9156-4.

[6]   J. Daniluk e E. Koert, «Between a rock and a hard place: The reasons why women delay childbearing,» 2017. [Online]. Available: http://sciedu.ca/journal/index.php/ijh/article/view/10914.

[7]   R. Pollycove, F. Naftolin e J. Simon, «The evolutionary origin and significance of Menopause,» March 2011. [Online]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433273/.

[8]   E. Velde e P. Pearson, «The variability of female reproductive aging,» [Online]. Available: https://watermark.silverchair.com/080141.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAbkwggG1BgkqhkiG9w0BBwagggGmMIIBogIBADCCAZsGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMRyVFcMHuS_8VlPIXAgEQgIIBbCBvvKNUUdfeYM8BfpsET4KmYTMXb6exhpADABlQvczEtZBG.

[9]   J. Hurt, M. Guile, J. Bienstock, H. Fox e E. Wallach, «The Johns Hopkins Manual of Gynecology and Obstetrics,» 2011. [Online].

[10] M. Bishop, «Paternal Contribution To Embryonic Death,» 1964. [Online]. Available: http://www.reproduction-online.org/content/7/3/383.short.

[11] A. Kersting e B. Wagner, «Complicated grief after perinatal loss,» June 2012. [Online]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3384447/.

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Lois Chan

Lois has worked in the health and skincare industry since 2004. Highly optimistic about aging, she is still pragmatic enough to prepare thoroughly for the future. PrimeWithTime.com is Lois' brainchild; a website offering scientifically researched solutions to challenges that people face in every stage of their lives. Join her on her journey for wisdom through the ages.

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