April 12, 2021

FACTS Infertility Awareness Series

Lifestyle Factors and their Impact on Fertility: A Review

By Heidi Bau

Editor’s Note: Our series to raise awareness and share the FACTS about infertility continues by examining the impact of lifestyle factors on fertility in both men and women. Heidi Bau summarized the 2013 article[i]published in the International Journal of Gynecology & Obstetrics by Petraglia et al titled, “The changing prevalence of infertility.” Her review ends by discussing the use of fertility awareness-based methods (FABMs) in the workup and management of infertility.

Introduction

Infertility is a prominent problem throughout the world that impacts people from all walks of life, regardless of income or race. With 9-30% of the population in low-income countries affected and 15% in high-income countries, infertility is not to be ignored. Medically defined as the inability to conceive after twelve months of unprotected intercourse, infertility can be caused by many factors. The article by Petraglia et al summarized below addresses the impact on fertility of various lifestyle factors, including smoking, diet, exercise, substance use, chemical exposures, stress, and delayed childbearing. Medical conditions contributing to infertility in men and women are discussed as well. 

Smoking

Smoking can negatively impact both male and female fertility. In men, oxidative stress can impair sperm production, motility, and morphology, and increase the risk of DNA damage. Smoking can also affect luteal hormone levels, fallopian tube contractility, sperm-egg interaction, and oocyte transport. Metabolites of cigarette smoke can be found in women whose partners smoke. These metabolites affect ovarian follicle development as well as the fallopian tubes, contributing to ectopic pregnancy. 

Weight, Diet, and Exercise

Being underweight or overweight can have a negative impact on fertility. Obese women have lower levels of sex hormone binding globulin (SHBG), which normally binds hormones like testosterone. Obesity also places women at higher risk for gestational diabetes and hypertension.

In men, a body mass index (BMI) outside of the normal weight range may be associated with poor sperm quality. Adipose tissue secretions result in impaired spermatogenesis and increased reactive oxygen species. A healthy diet, weight loss, and exercise can all improve fertility in both men and women. However, moderation in exercise is important; over-exercising can strain the body and impair fertility. 

Caffeine and Alcohol

Consumption of both caffeine and alcohol has been shown to increase the time it takes to conceive. Although controversial, studies have found that heavy coffee consumption alters the level of hormones in the body, increases the risk of miscarriage, and is associated with low birth weight. The association of alcohol with birth defects is well known. While the exact amount of alcohol necessary to cause these detrimental effects is debated, both men and women experience impaired fertility with chronic alcohol consumption. 

Environmental Pollutants and Oncofertility

Environmental toxins such as radiation, pesticides, and phthalates can all lead to infertility. Cancer and its associated treatments can also negatively impact fertility. In people diagnosed with cancer at a young age, it is important to address their fertility early on and follow this closely over time. 

Psychological stress

As seen with amenorrhea, stress can have a significant impact on fertility. A stressful career may decrease a woman’s likelihood of conception, and a high workload decreases the odds of successfully completing a pregnancy. A decrease in both sperm count and motility are associated with stress in men.

Delayed Childbearing

In an increasingly career-focused world, many women now choose to pursue a career before they start a family. This has led to a delay in the age at which women consider childbearing. Since fertility declines with age beginning at age 32, by the time a woman has established her career, she may find it more difficult to conceive. This finding can be distressing, as she now has a limited time before she will become infertile due to age. Delaying conception may also increase the risk of spontaneous abortion or miscarriage as well as congenital defects.

This age-related decline in fertility is not limited to females. Men also experience a decline in fertility as they grow older, although not as extreme as in women. Increasing age increases men’s risk of trauma, cancer, and inflammation in the reproductive organs. They may also experience decreased levels of testosterone. Also, as many as 40% of men with infertility may have a varicocele, an abnormal distention of the testicular venous plexus. These factors may all contribute to male infertility.

Medical Conditions Affecting Fertility

A variety of medical conditions are known to contribute to infertility. In secondary hypothalamic amenorrhea, the communication between the hypothalamus and the pituitary gland is ineffective, impairing fertility. Chronic stress can be the root of the problem if the body cannot appropriately adapt to stressors. Without adaptation, gonadotropins are reduced and cannot stimulate a menstrual cycle effectively.

Another medical condition impacting fertility is polycystic ovarian syndrome (PCOS). One in four women with PCOS will experience infertility, and they may also experience irregular periods, anovulation, hyperandrogenism, increased weight, and insulin resistance. Asymptomatic uterine myomas (fibroids) may also impair fertility. These benign tumors of the uterus may lead to future problems due to their accumulation and growth. This may cause abnormal bleeding and impaired uterine contractility. The presence of myomas has also been associated with increased risk of miscarriage, preterm delivery, and other complications of pregnancy.

Endometriosis is another culprit impairing fertility which can also lead to dysmenorrhea, pelvic pain, and gastrointestinal pain. The association of endometriosis and infertility is strong. In some studies, as many as 30-50% of women with infertility have endometriosis, and infertile women are 6-8 times more likely to have endometriosis. Several proposed mechanisms explore the impact of endometriosis on fertility. One mechanism may involve an inflammatory environment that impairs the interaction between sperm and egg, while others point to adhesions affecting oocyte descent, depletion of the ovarian reserve, and decreased endometrial receptivity. 

Discussion

The article by Petraglia et al provides a broad overview of numerous factors contributing to infertility. This information is important for both clinician and patient when pursuing an evaluation for infertility. By altering modifiable factors in a patient’s life, the couple may optimize their fertility and successfully conceive.

For the physician, this information emphasizes the importance of thorough history-taking to identify factors that may contribute to a couple’s infertility. For the patient, this helps to promote understanding that many factors impact fertility, and some of them are potentially modifiable. It also helps patients understand they are not alone, as infertility is a worldwide problem.

The rising prevalence of infertility warrants a more in-depth investigation of each of these factors. Furthermore, several of them require more research before quantitative statements can be made about their impact on fertility. For example, there is need to quantify the amounts of caffeine and alcohol that adversely impact fertility.

FABMs in the Management of Infertility

In future research, it would be beneficial to examine the impact of fertility awareness-based methods (FABMs) to assess and manage infertility. These methods promote charting a woman’s natural signs and symptoms to monitor her health and fertility. Many of the underlying problems causing infertility can be diagnosed by FABM chart analysis and subsequently treated in ways that work with a woman’s natural cycle.[ii]

Furthermore, by incorporating FABMs into their practice, physicians have more tools to identify and treat problems leading to infertility much earlier. In fact, Natural Procreative Technology, a natural approach to women’s health based on the Creighton Model, has been shown to be as effective as more invasive infertility treatments.[iii][iv] Educating physicians about the practical applications of FABMs in the management of infertility will magnify the impact of studies like this one, and will equip physicians and patients with more ways to diagnose and monitor their fertility.

References

[i] Petraglia F, Serour GI, Chapron C. The changing prevalence of infertility. International Journal of Gynecology & Obstetrics. 2013;123:S4-S8. doi:10.1016/j.ijgo.2013.09.005.

[ii] Infertility. Accessed July 3, 2020. https://www.naprotechnology.com/infertility.htm.

[iii] Stanford_Outcomes-from-Treatment.pdf. Accessed July 3, 2020. https://www.factsaboutfertility.org/wp-content/uploads/2018/08/Stanford_Outcomes-from-Treatment.pdf.

[iv] Tham-Schliep-Stanford-Natural-Procreative-Technology-for-Infertiliy-and-Recurrent-Miscarriage-1.pdf. Accessed July 3, 2020. https://www.factsaboutfertility.org/wp-content/uploads/2018/08/Tham-Schliep-Stanford-Natural-Procreative-Technology-for-Infertiliy-and-Recurrent-Miscarriage-1.pdf.

About the Author

Heidi Bau

Author Bio: Heidi Bau wrote this review as a second-year medical student at the University of North Dakota while on the FACTS elective in fertility awareness. She plans to specialize in family and community medicine. She is a FACTS ambassador and has enjoyed improving her knowledge of natural fertility by participating in FACTS webinars and the elective. She recently invited a FACTS speaker to her medical school to enhance knowledge of women’s health.