If the lady is having periods after intercourse it means that she is unlikely to conceive.A pregnancy
test, no matter if it's blood or urine, only becomes
positive after implantation
when the fetus has attached to the uterine
wall and connects with the mother's blood system. Implantation, when the fertilized egg implants into the endometrium, happens about 9 days after ovulation and fertilization (range: 6-12 days).If you are pregnant, then the blood pregnancy test is usually positive within 3-4 days after implantation or about 10-11 days after fertilization and ovulation. The urine pregnancy test is positive several days after the blood test
becomes positive.Hope this helps you.