I found this at
http://ezinearticles.com/?Can-You-Get-Preg
nant-on-Your-Period?&id=449291
Although your menstruation is commonly believed to be a “safe” period of time in your monthly cycle, you can still get pregnant while you are on your period. This truth is basically due to the fact that some women have extremely short cycles, which cause their ovulation to come shortly after their periods. For these women, ovulation follows fairly closely after they are on their period, which increases their risk of pregnancy. You can only get pregnant on your period if the egg that your body released is present, or if the sperm manage to stay until the egg is there.
Sperm have the amazing ability to live for a couple of days inside of the female body, which is why you can get pregnant on your period. Semen comes equipped with a food supply for the sperm, so they have the energy to make it for a while. This amazing biological fact means that you can actually get pregnant on a different day than when you had sexual intercourse. That sounds strange, but it is true!
If you have sexual intercourse while you are on your period, and the sperm stays alive for a few days inside of you, and then you ovulate while the sperm is still there, you can and will get pregnant on your period.
It is important to remember that this is not the usual order of events in your body, so that is why it isn’t common to get pregnant on your period. Some women can not actually get pregnant on their period, but others, due to the timing of their periods or the erratic nature of their ovulation, can get pregnant on their period. There is not a good way to tell whether you can get pregnant on your period, unless you have already gotten pregnant in the past while on your period. In this case, you would know that the answer is “YES!”
The moral of the story is that you can get pregnant on your period. This is why it is important to continue to use your birth control method during this time if you are not trying to become pregnant. If you are on the birth control pill or a vaginal hormone ring that is removed during menstruation, you are still covered while on your period. The hormones do not leave your body in that period of time, as long as you use your method as directed. And birth control pills cannot protect you from sexually transmitted infections or HIV, so using condoms at all times is a smart idea. Even though you are unlikely to get pregnant on your period, you still have the same risk of contracting a sexually transmitted infection, including HIV.
