Assault Rape Pregnancies Are Rare

http://www.physiciansforlife.org/content/view/492/26/
excerpt:
Finally, factor in what is certainly one of the most important reasons why a rape victim rarely gets pregnant, and that's psychic trauma. Every woman is aware that stress and emotional factors can alter her menstrual cycle. To get and stay pregnant a woman's body must produce a very sophisticated mix of hormones. Hormone production is controlled by a part of the brain that is easily influenced by emotions. There's no greater emotional trauma that can be experienced by a woman than an assault rape. This can radically upset her possibility of ovulation, fertilization, and implantation.