Tri-Sprintec, the contraception said to work in one of 3 ways: 1) prevents ovulation (primary), 2) dyhydrating cervical muscous keeping egg and sperm away from each other, and 3) possibly making the fertilized egg unable to attach to the uterine wall. The third of course could be condered abortive, even if unintentional...Is there credence to the possibility of #3...? If so, is there a pill that can be recommended that only works by methods 1 and 2...?? Thanks!