Stress plays a prominent role in our modern day world and is increasingly being cited as a contributing factor in a wide array of diseases and disorders. In addition to the more well known associations with heart disease and certain auto immune disorders, stress has now been shown to interfere with the fertility process.
Stress is one factor among many that can impede fertility, but it is also one factor that is under the individual’s control. Couples in pursuit of optimum fertility should make it a primary goal to seek methods that will induce the "relaxation response" as opposed to the "stress response". There are a number of things that occur when the body is subjected to stress. The hypothalamus responds to stress by releasing a hormone called corticotrophin. Other stress hormones that the body produces are catecholamines and cortisol. These stress hormones, once released, can have a very significant effect on the fertility process including:

• Complete suppression of the menstrual cycle in women
• Reduction of sperm counts in men

The female reproductive tract contains catecholamine receptors. Under stress, the release of catecholamines causes interference with the transportation of gametes through the fallopian tube and can impede the fertility process.
The brain is the primary regulator of stress in the body and it has been shown that thoughts, emotions and moods can play a causative role in stress management. Using a complex system of neuronal chemicals called neuropeptides, the brain is able to communicate with every system in the body. These “molecules of emotion” are capable of either triggering or curbing the body’s stress-response depending on how the sympathetic nervous system in the brain perceives its environment.
Stress will cause physiological changes and the release of certain hormones that can make the fertility process more difficult. We must “stack the deck” in favor of fertility by making stress reduction an integral part of a couple’s journey towards conception.

Wilson, John F, PhD - Kopitsky, Elizabeth, PhD (2002)
Stress & Infertility - Dept of Behavioral Sciences, Univ of Kentucky College of Medicine
Fukui, Hajime - Yamashita, Masako (2003)
The effects of music and visual stress on testosterone and cortisol in men and women:
Neuroendocrinology Letters
Sex Hormones Plunge With Depression (2004)
The Journal of Biological Psychology
Mechanick-Braverman, Andrea, PhD
Stress and Infertility