"From a scientific standpoint, what's legitimate and fair to say is that a woman who is raped has the same chances of getting pregnant as a woman who engaged in consensual intercourse during the same time in her menstrual cycle," said Dr. Barbara Levy, vice president for health policy at the American Congress of Obstetricians and Gynecologists.
One widely accepted study suggests a 5 percent pregnancy rate following rape, resulting in 32,000 pregnancies each year.
The report was from the Medical University of South Carolina and was published in the American Journal of Obstetrics and Gynecology and cited by the U.S. Centers for Disease Control and Prevention.
But placing an exact figure on post-rape pregnancy is problematic, primarily because rape is thought to be underreported. Another factor is the availability of over-the-counter emergency contraception, which can prevent fertilization when taken after intercourse.
One study from the journal Human Nature in 2003 suggests pregnancy rates are higher after a rape when compared with consensual sex because of the inconsistency of birth control use.