MEDICAL
ABORTION
The
idea of using drugs to induce abortion is centuries old.
Medically proven therapies, however, have come about only
in the last 50 years. Essentially, drug induced abortions
mimic a miscarriage. The pregnancy ends and the uterus
empties. Thus, an important issue in medical abortion is
how to manage pain, bleeding, and potential complications.
Medical
abortions should always be performed under the care and
supervision of trained and skilled medical personnel. Until
recently, medical abortion was restricted to later gestational
age. Today in the U.S., medical abortion provides an alternative
to surgical abortion early in gestation. This is especially
important for women who lack access to the full array of
reproductive care services.
Different medicines may be used to induce an abortion,
depending on the stage of the pregnancy. “Early”
abortions take place in the first trimester; nearly 90%
of all legal abortions in the U.S. are early, occurring
within the first three months of gestation. In these cases,
a one of two combinations of medicines is utilized: methotrexate/misoprostol
or mifepristone (also known as RU-486).
Each
treatment has a different effect on the body (see below)
and both treatments can be taken up to 49 days after the
last menstrual period begins. These regimens require several
clinic or doctor’s office visits. Both are about 95%
effective. In other words, approximately 1 in 20 women
who undergo medical abortion will need to have a surgical
abortion because the medication was not effective.
Methotrexate
Since
1953, methotrexate has been used in the US as an FDA approved
treatment for certain types of cancer. Among other important
medical uses, low-dose methotrexate has also been used for
treating ectopic (outside the uterus) pregnancies. It works
by interfering with tissue growth, uterine implantation,
and fetal development. Currently, clinicians prescribe
methotrexate for early abortion. It is usually given in
the form of an injection or shot. A few days later, a second
drug misoprostol is given either orally or as a vaginal
suppository. Misoprostol is a prostaglandin, a naturally
occurring substance. It causes the uterus to contract,
emptying it of the lining and fertilized egg, and thereby
ending the pregnancy. With methotrexate, 80-85% of women
will abort within 2 weeks. Some may take longer and require
more misoprostol.
Mifepristone
Also
known as RU-486, mifepristone was first licensed as an abortifacient
in France in 1988. Since then, it has been used by millions
of women in Europe and China. It has been legally available
in the U.S. since 2000. Mifepristone works by blocking
the hormone progesterone. Without this essential hormone,
the lining of the uterus breaks down, the cervix softens,
and bleeding occurs. As with methotrexate, enough prostaglandin
is given to help the uterus contract and expel its contents.
With mifepristone, 95-97% of women will abort within two
weeks.
