Most people probably aren't aware that many artificial contraceptives are actually abortifacient --
they can cause abortions. This fact is usually not something birth control advocates want to talk about because of its very grave moral implications, not only for Catholics but for many non-Catholics and even agnostics and atheists as well. The Catholic Church has always been against abortion and artificial contraception, but many other groups allow artificial contraception while prohibiting abortion. Such groups would of course be very concerned if they were to realize that contraceptives are also abortifacient.
Basically, most contraceptives work by preventing ovulation and/or preventing the sperm from entering the fallopian tubes.
The problem, however, is that this doesn't always work. In fact, it doesn't work a significant portion of the time. Sometimes a woman ovulates -- known as "breakthrough ovulation" -- even when a women never fails to take a pill at the right time. It is estimated that breakthrough ovulation occurs from 2% - 10% of the time. The progestin-only pill, also known as the mini-pill, may allow ovulation 40%-60% of the time. A woman on the pill can -- and often does -- conceive a child.
When ovulation occurs and a woman conceives, there is still another back-up, abortifacient function performed by contraceptives such as the pill. The progestin contained in the pill, for example, irritates the lining of the uterus, causing it to thicken and prevent implantation of the newly conceived child. With nowhere to implant, the child is eventually flushed out of the woman's body and destroyed.
This is an early chemical abortion.The IUD, on the other hand, does not prevent ovulation. Rather, it works by causing changes to the inner lining of the uterus. This also prevents the newly-conceived child from implanting in the womb.
It is also abortifacient.All oral, injectable, and implantable contraceptives widely distributed in the Philippines are abortifacient and work in ways similar to those described earlier.
Incidentally, the Philippine Constitution recognizes that an unborn child has rights and must be protected from the moment of conception. Article II, section 12 states:
The State recognizes the sanctity of family life and shall protect and strengthen the family as a basic autonomous social institution. It shall equally protect the life of the mother and the life of the unborn from conception. The natural and primary right and duty of parents in the rearing of the youth for civic efficiency and the development of moral character shall receive the support of the Government.
That means that abortifacient contraceptives (which are most of contraceptives distributed in the Philippines) are violating the Constitution. They should therefore be made illegal.
For more information, check out the links below (these will be regularly updated as more information becomes available):
The exception is often found in Catholic hospitals, whose physicians may not give the "post-rape pill." 