My gf and i had sex 1 day after her menstruation ended. in the middle of it we had unprotected sex for a couple of seconds. i didn't finish. that was a week ago and she is concerned that she might be pregnant. what are the chances for that?

In the middle of menstruation or middle of cycle? If middle of mens very low if middle of cycle time will tell.

Pregnancy has been documented from exposure at any point in a womans' cycle, including during menses. Those pregnancies are more often if a woman is not regular, but they do happen. If this exposure doesn't get her pregnant consider taking precautions in the future. There are no absolutely safe days except for when you don't have sex.

Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.