The types of abortion available to women today are almost as varied as women's reasons for having them.

Perhaps the best known method is the dilation and curettage (D and C). Usually performed during the first 12 weeks of pregnancy, it involves cervical dilation on forcing open the neck of the womb - and scraping out the contents with a spoon or scoop-shaped surgical knife called a curette.

This method is being used less frequently, as more clinics and physicians switch to the far safer vacuum method for performing first trimester abortions.

The vacuum aspiration method involves dilating the cervix and using a machine called a vacuum aspirator to suck out the fetus and any other tissue. The method generally involves little pain for the woman and is aesthetically one of the least upsetting methods of abortion. To the untrained eye the vacuum only appears to be removing a heavy menstrual flow.

While other methods are used during the first 12 week - when about 90 per cent of all legal abortions are performed - the D and C and vacuum aspiration are considered the safest.

Three methods are predominant for performing abortions during the second trimester - 12 to 24 weeks - although in the District of Columbia abortions are only available up to 20 weeks. The method thought to be safest is vacuum aspiration.

This type of abortion, which can be performed up to about 17 gestational weeks - weeks of fetal development, as opposed to weeks since the onset of the last menstrual period - combines use of the vacuum aspirator and D and C.

Some physicians first use the vacuum aspirator to remove the placenta and fluids, then cut the fetus with a curette and remove it with forceps. Others use the forceps to remove all the material, then finish with the vacuum aspirator to remove any remaining tissue or fluids.

The second safest method of second trimester abortion is the saline abortion that involves using a large hypodermic needle to withdraw the fluid surrounding the fetus, then replacing the fluid with a saline, or salt, solution.

The saline solution is supposed to kill the fetus and cause the woman to go into labor. The disadvantage of the method is that the woman goes through a normal period of labor, with all the inherent risks, and then delivers a dead fetus.

The least safe of the three methods is the so-called prostaglandin abortion. This involves injecting the woman with large doses of prostaglandin, a natural substance found, among other places, in menstrual fluid.The substance causes quick, and intense labor and delivery.

Again, the risks to the woman's health and life increase because, among other things, she has to go through the childbirth process. According to the federal Center for Disease Control, the overall death rate for women who abort during the second trimester is 13 per 100,000 as opposed to 1.7 per 100,000 in the first trimester.

The risk of death from abortion is not constant within each trimester. It is riskier, for example, to abort in the 11th week than it is in the 9th. And it is riskier to have an abortion at 16 weeks than it is at 14. The mortality figures commonly used are averages for each of the trimesters.