Root Causes of Fertility Issues

Infertility affects 7% of married women in the United States. Optimizing fertility is not just about female health. 35% of infertility cases had a male factor with or without a female factor making preconception health important for both men and women (1).

Many factors can impact fertility including diet, lifestyle, and imbalances. Here we take a quick look at some of the root causes of fertility issues and the role of a dietitian in using nutrition to support fertility.

Vitamin & Mineral Deficiencies

While the role of vitamins and minerals has been well recognized during pregnancy, research is beginning to show the vital roles that micronutrients play in fertility. Below are a few key micronutrients and their role in the stages of fertility (2,3):

Folate—plays a role in egg quality, maturation, fertilization, and implantation.

Vitamin A—plays a role in egg quality and embryo development

Selenium—low selenium has been linked with infertility in men and women. In women, low selenium may play a role in making the endometrium less receptive to implantation.

Zinc—important in ovulation and menstrual cycle, spermatogenesis, and regulation of sperm motility

Antioxidants—including vitamin E, C, and A combat oxidative stress. Oxidative stress has been shown to interfere with fertility.

Low levels of vitamin D, B6, and B12 have been found in women who struggle to conceive indicating these vitamins may play an essential role in fertility as well. Screening for deficiencies and restoring micronutrient levels may improve fertility (3).

Poor Diet

Diet plays an essential role in fertility for both men and women. Overly restrictive diets can lead to inadequate body fat resulting in irregular menstruation and ovulation while also potentially eliminating key nutrients necessary for fertility (4).

Diets high in saturated and trans fats are linked with lower fertility. In contrast, a preconception diet rich in fruits, vegetables, whole grains, plant proteins, and unsaturated fats has been shown to lower the risk of infertility (5).

Diet can be an important factor in improving fertility. A dietitian can work with you to help make incremental, manageable, and impactful changes to optimize your diet.

Excessive Exercise

Physical activity can be beneficial for overall health as well as fertility. However, like many things, more doesn’t always mean better. One study showed that men who participated in moderate exercise had better sperm morphology than those with low activity and those with high levels like competitive sports players or athletes. In women, vigorous exercise can lead to increased risk for anovulation and implantation failure resulting in difficulty conceiving (5).

The relationship between exercise and fertility is complex. It’s important to consult with a doctor on what level of exercise is best for you. Additionally, remember that exercise requires proper nutrition to nourish, protect, and fuel your body as well as support your fertility.

Unmanaged Stress

Stress is common in today’s world. Prolonged and unmanaged stress can lead to changes in hormone levels, contribute to inflammation and negatively impact fertility. Stress may reduce sperm density, total sperm count, motility and morphology (5). In women, stress can interfere with egg quality and development (6).

While there are many stressors in life it is important to acknowledge the stress that can occur during preconception particularly in couples struggling with infertility. From waiting for results to the many doctor’s appointments, and especially during fertility treatments this process can be stressful. It is important to be open about the stress you may be feeling, seek help from a professional, and actively work to manage your stress (7).

Gut Imbalance

Gut health in relation to disease is becoming an increasingly popular topic. Your gut is filled with bacteria and microbes that when in balance can help improve digestion and immune function (8). A recent study suggested a gut-hormone axis in which the gut microbiota influences hormone levels, specifically estrogen. When there is less diversity in the gut there may be less circulating estrogen which could play a role in several diseases as well as have implications for infertility (9).

While more research is needed, it is clear that a healthy gut is beneficial. Consult with a dietitian to learn more about how to keep your gut microbiome diverse.

Hormonal Imbalance

Hormonal imbalances are a major cause of infertility. Hormonal disorders can lead to the production of hormones at levels that are too high or too low. This can lead to irregular menstrual cycles, lack of ovulation, pelvic cramps, and weight fluctuation which can all contribute to fertility issues (10).

Some causes of hormone imbalances include problems with the thyroid gland, hypothalamus, and pituitary gland. Stress, birth control pills, some diseases, and some medications can also interfere with normal hormone production (10).

A plan including things like medication, dietary changes, and lifestyle changes can be developed to manage hormonal imbalances and improve fertility. However, many hormonal imbalances go undiagnosed. Work with a healthcare professional to screen and identify any imbalances that may be interfering with fertility.


PCOS is a common hormonal disorder affecting approximately 10% of women. Insulin resistance and increased production of androgens are common in PCOS. Some symptoms of PCOS can include infrequent menstrual periods, infertility, acne, and increased hair growth on the face, chest, and stomach. Medication, surgery, and lifestyle changes can help manage PCOS. Research has shown that physical activity and diet can improve PCOS symptoms (11). Some research shows specific diets like the Mediterranean Diet and Ketogenic Diet may be helpful (12,13).

Undetected Thyroid Disease

Undetected thyroid disease is a high cause of subfertility. The thyroid produces hormones that are important in several processes including reproduction. Hypothyroidism is when not enough thyroid hormone is being produced. It can be caused by immune disorders, iodine deficiency, radiation or certain medications. Subclinical hypothyroidism is not always indicated on typical lab tests resulting in undetected thyroid disease. In men, low thyroid function can lead to low sperm production. In women, hypothyroidism can result in a lack of ovulation and issues with egg development. When properly diagnosed lifestyle changes, medication, and nutrition can be utilized to manage the condition. (14,15).

The Dietitian’s Role

Nutrition intervention plays a key role in supporting fertility by targeting the root cause of the issue. At FRESH we take an individualized approach tailoring nutrition intervention to support each patient’s unique needs. Ready to take the next step and develop a customized plan to improve your fertility? Schedule an appointment to learn more about the role of nutrition in fertility.


1. Features – Infertility | CDC

2. An impact of selected micronutrients on fertility | Żak | Journal of Education, Health and Sport (umk.pl)

3. The Impact of Preconceptional Multiple-Micronutrient Supplementation on Female Fertility (nih.gov)

4. The effect of underweight on female and male reproduction – ScienceDirect (uh.edu)

5. Gale OneFile: Health and Medicine – Document – Lifestyle factors and reproductive health: taking control of your fertility (uh.edu)

6. IJMS | Free Full-Text | Stress and the HPA Axis: Balancing Homeostasis and Fertility | HTML (mdpi.com)

7. The relationship between stress and infertility (nih.gov)

8. The Human Gut Microbiome: From Association to Modulation: Cell

9. Estrogen–gut microbiome axis: Physiological and clinical implications – Maturitas

10. Infertility-Related Risk Factors: A Systematic Review (ijwhr.net)

11. Polycystic Ovarian Syndrome (eatright.org)

12. Nutrients | Free Full-Text | Adherence to the Mediterranean Diet, Dietary Patterns and Body Composition in Women with Polycystic Ovary Syndrome (PCOS) | HTML (mdpi.com)

13. Gale OneFile: Health and Medicine – Document – Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. (uh.edu)

14. Biochemistry of infertility – ScienceDirect

15. Thyroid dysfunction and subfertility – PubMed (nih.gov)

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