Most abortions, about 88%, occur in the first trimester of pregnancy, or the first 12 weeks. Dr. George Tiller, who was slain over the weekend, performed abortions well into the second trimester, sometimes past the 22nd week.
Most doctors don't perform late-stage abortions. Nationally, only 1.3% of all reported legal abortions occurred at 21 weeks or more gestation. A slightly higher percentage, 3.7%, occurred at 16 to 20 weeks gestation. For a by-the-numbers look at abortion in the United States, as much as it's possible, here's the full report from the CDC.
Included is a state-by-state look at those abortions. Of legal abortions occurring at 21 weeks or more gestation, most appear to be in New York. That state reported 2,956, followed by Georgia with 1,094 and New Jersey at 950. California doesn't tell.
In a 1987 survey of abortion patients, women explained their reasons for seeking later-than-normal procedures. Of those who had an abortion at 16 or more weeks gestation, 71% said they either didn't know they were pregnant or hadn't known how far along they were in the pregnancy.
Here's the abstract, via Pubmed, of that survey, published in Family Planning Perspectives the following year. And here's a broader study of women's reasons for getting abortions, published in Perspectives on Sexual and Reproductive Health in 2005.
Now for the how. It varies by stage of pregnancy, by the needs of a woman and by the recommendations of her doctor. For a second-trimester abortion, the primary method is dilation and evacuation, more commonly called a D & E. Here's one explainer, from WebMD.
But to understand, more fully, the types of abortion and how they vary by stage of fetal development, there's this from Brown University: Abortion: Methods of Terminating a Pregnancy at Different Stages of Pregnancy and Fetal Development.
This is not an enjoyable read, but it may be a needed one. As the introduction states:
"While the political and moral debates about abortion generally have no root in the medical science of the procedure itself, a correct understanding of the biology of the procedure is necessary for developing educated opinions about the issue of abortion."
-- Tami Dennis
Photo: A plant was left Sunday outside Dr. George Tiller's clinic, Women's Health Care Services.
Credit: Kelly Glasscock / Getty Images