Clinical research has demonstrated the following facts concerning stress and fertility:

Stress has an immediate, chemical effect on endocrine function through its major motivator the hormone cortisol. Stress is an adaptive response to perceived or real danger, referred to as the fight or flight response.

This stress response is an evolutionary function that supported survival during life-threatening situations in primitive times. In the face of danger, an enormous physical effort is asserted to mobilize the body including increased blood flow to the muscles from the heart and increased oxygen flow for breathing, both functions are required to meet the metabolic demands of fight. This is the job of the hormone cortisol. In moments of danger, the hypothalamus signals the adrenal glands to release the hormone cortisol. The result is immediate:

Increased blood flow to muscles.
Decreased blood flow to internal organs.
Increased heart and respiratory rate.

Once the real or perceived danger is resolved cortisol levels return to normal. This is a very different situation from the stress response of the modern day. Stress has a profoundly negative impact on other areas of our life that are important to reproductive function such as sleep, eating habits, sex, drive, mental health. Stress brought on by anxiety and/or depression can alter immune function. We have all heard about how the effects of depression can lower our immunity, making us more vulnerable to colds and other viruses during emotionally stressful periods. Sometimes its outcome is the use of chemical substances such as alcohol and cigarettes.

The result is that cortisol levels in the body remain elevated and this can have severe consequences for fertility. Cortisol down-regulates bodily functions associated with rest and digestion, including reproductive function. The increased blood flow to the musculature associated with the stress response comes at the expense of the uterus and ovaries. Some of the physical symptoms of stress are: tight muscles, shallow and quick breathing, poor digestion and poor sleep are some of these symptoms, which can be monitored and managed with mind/body skills.