I have a crazy question that requires a (crazy?) medical professional's attention.

[Motown_Johnny]

I am curious what the chances are of a fertilized egg failing to attach itself to the uterine wall.


As I understand it (and I could easily be wrong) much of the fight over contraception is that medications are being used which prevents a fertilized egg from attaching itself to the uterine wall.


Because this sometimes happens naturally, and because no form of birth control is 100% effective, I would like to try and work out some numbers and try to present an argument that women are simply trying to increase the odds of this happening.


I know it sounds crazy, I admitted that up front, but because of the "life begins at conception" point of view from religious fundamentalists I think that can be countered with a "God does this to women all the time" argument.

Thanks for any help. When something like this pops into my head I just need to work it out, even if it ends up not making any sense.

[sharp_stick]

1. Not a really well understood

number but most estimates are that more than half, quite a few more according to some, either don't implant or spontaneously abort. In most cases this happens very very early and isn't even known to the woman.

Here's a link to a 2004 Discover article that does a pretty good job with the question.

http://discovermagazine.com/2004/may/cover/article_view?b_start:int=2&-C

[The Wielding Truth]

2. I found this. It might help.

http://www.unc.edu/news/archives/jun99/wilcox2.htm

[TheWraith]

3. Not a medical professional, however...

If I recall the stats correctly, about 30 to 50% of fertilized eggs fail to attach.

[Arkansas Granny]

4. I found some information, but I don't think it answers your specific question.

A miscarriage is a pregnancy loss that occurs before 20 weeks, well before the fetus is able to survive outside the womb. About 10 to 15 percent of recognized pregnancies end this way (1, 2). As many as 40 percent of all pregnancies may end in miscarriage, because many losses occur before a woman realizes she is pregnant (3).

http://www.marchofdimes.com/baby/loss_miscarriage.html

These stats are for miscarriages due to any cause, not just failure to implant. I've always wondered how people could claim that each fertilized egg is so precious to god when so many of them are shed so early in pregnancy, sometimes before a woman even knows she is pregnant.

[sinkingfeeling]

5. Less than 66% of all fertilized ovum result in the full-term birth of a baby.

"Actually, the statistics are more grim than Pence admits. Only about 50% of all zygotes successfully implant in the uterine wall and become embryos. And only about 65% of all embryos lead to live births; the rest (about 35%) are lost to natural miscarriage. Therefore, slightly less than one third of all zygotes lead to live births. These statistics come from Gregg Easterbrook in "Abortion and Brain Waves" (2000) and from Morowitz and Trefil, The Facts of Life. Science and the Abortion Controversy (New York: Oxford University Press, 1992). Easterbrook: only about 32.5% (65% of 50%) of all fertilized ovum are carried to term. Morowitz and Trefil: "slightly fewer than a third of all conceptions (72 percent of 45 percent) [or 32.4%] lead to a fetus that has a chance of developing." Morowitz and Trefil point out that not all fertilizations result in successful cell division -- some fertilized eggs don't even become blastocysts. "

[mike_c]

6. it's likely that MOST fertilizations result in aborted embryos....

eom

[notadmblnd]

7. Spontainous abortions occur all the time and many women don't even know theyre pregnant

I'm not medical expert, but I have given birth and I have had a miscarriage.