How Many Zygotes Are You Killing?

Libby Anne crunches and re-crunches some numbers:

A few weeks ago I came upon a blog post by Sarah of Who I Am Without You comparing the number of zygotes—i.e. fertilized eggs—flushed out of a woman’s body when she is on the pill with the number flushed out when she is not on the pill. Sarah’s numbers were as follows:

Without Birth Control:

  • Out of 100 fertile women without birth control, 100 of them will ovulate in any given month.
  • Out of those 100 released eggs, 33 will become fertilized.
  • Out of those 33, 18% will be rejected by the uterus.
  • In a group of 100 women not on birth control: 6 zygotes will “die”

With Birth Control:

  • Out of 100 fertile women on birth control, around 6 of them will ovulate in any given month.
  • Out of those 6 released eggs, only 2 will become fertilized.
  • Out of those 2, 100% will be rejected by the uterus.
  • In a group of 100 women on birth control: 2 zygotes will “die”

I wondered about the numbers Sarah used, so I went looking for verification. I decided to use pro-life websites as I did this, not because I think they necessarily have the numbers correct but rather because if I use their own numbers in my analysis I can’t be accused of using biased liberal numbers.

Great data.