Following my column, “June 7: The Pill Kills Day,” I received emails expressing similar thoughts from good pro-life friends like this:

[B]efore going along with American Life League’s campaign against birth control pills, your blog (and column) should do more than merely read off the FDA’s label regarding birth control pills and leave it as if the FDA’s label is gospel truth.

ec uh oh.jpg

The FDA label says the same thing about emergency contraception and recent study after recent study is showing how unlikely it is that EC has a post-conception effect.
There are numerous scientific studies on this issue and not one of them (at least that I’ve read) has conclusively proven that birth control pills prevent the implantation of conceived embryos….

[T]here’s a difference in saying there is a possibility (and no one is sure how strong a possibility) that the pill might in the case of breakthrough ovulation prevent a human embryo from implanting and saying with certainty that the “pill kills.”
From what I’ve read, there is also a possibility that breast feeding might have similar effects to the effects the pill has on a woman’s body. But I’m not seeing ALL claim “Breastfeeding kills.”

As I understand it, to this day no one can unequivocably state how the birth control pill works. But almost all pill packaging lists 3 possibilities, 1 of which is it can make the uterus impermeable to the 5- to 9-day-old embryo attaching.
Why argue against this possibility, particularly when knowing the information is published by those wishing it weren’t so? If they could not say it, they would not say it. And if there is a possibility, should one play contraceptive Russian Roulette? Don’t we always err on the side of life?
Emegency contraceptives are just mega-doses of artificial hormones found in birth control pills. I have read the opposite than my friend about EC and killing preborns. Since there is greater likelihood the egg has been fertilized by the time a woman takes an EC (within 72 hours after unprotected sex), there is greater likelihood an EC aborts. CWA lists all the scientific arguments.
The argument that breastfeeding may have the same mode of action as contraceptives so why oppose contraception is the equivalent in my mind to arguing that since miscarriages may have the same mode of action as abortions why oppose abortion.
Further, here is how breastfeeding appears to inhibit pregnancy, from my Human Anatomy and Physiology textbook:

Although it is possible for a woman to become pregnant during the period that she breast-feeds her child, menstrual cycles seem to be inhibited, at least for a time, while the mammary glands are active.

breastfeeding.jpgAlthough the mechanism responsible for this effect is not well understood, it is thought that prolactin may suppress the release of gonadoptropins [Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)] from the anterior pituitary gland.

In any event, menstrual cycles may not resume for some time following the birth of an infant that is breast-fed. On the other hand, after several months of breast-feeding, FSH is usually released, and the monthly reproductive cycles are reestablished.

If breastfeeding inhibits the menstrual cycle altogether, then it inhibits egg maturation and release, since the gonadotropins trigger that. This is what I would expect anyway. God would not purposefully cause abortions. He does allow miscarriages, but that is a different topic.
The menstrual cycle is a beautiful, extremely complex hormonal dance. Every time I study it I marvel anew and give glory to God. From my textbook (click to enlarge):
menstrual cycle 001.jpg
My NFP friends can jump in here with more information how breastfeeding causes natural family spacing.