Abortion and medical problems
Do abortions cause miscarriages later in life?
What causes miscarriages?
Anthony R. Scialli of the Department of Obstetrics and Gynecology at Georgetown
University Medical Center states that "Most doctors consider a miscarriage
as a protective mechanism that prevents the continued pregnancy of a nonviable or abnormal
embryo or fetus." 1 The apparent incidence of miscarriage has
increased over the past 2 decades with the development of more sensitive pregnancy tests.
In the past, women may not have noticed many miscarriages. Currently, with home tests capable of
detecting pregnancy as soon as 2 days before a missed period, more women have become aware
of being pregnant and subsequently having a miscarriage. Dr. Scialli quotes recent studies which indicate that about 31%
of pregnancies end in miscarriage. This rises to over 50% for women over 40 years of age.
Causes of miscarriage include:
||Genetic defects: Most embryos or fetuses that miscarry have been
conceived with an abnormal number of chromosomes. Others have the correct number of
chromosomes but involve an abnormal gene.
Immune system: Since the embryo contains foreign genetic material, it
can trigger the woman's immune system, which treats it a foreign substance. A blocking
mechanism normally acts to inhibit the immune system during pregnancy. However, it can
In some cases, a woman's immune system will attack the placenta, even though it is made up
of the woman's cells.
Hormones: Too low a level of the hormone progesterone can cause a
State of the uterus: A miscarriage may be caused by the uterus having
an abnormal shape, or adhesions due to previous surgeries.
Infections: Some bacteria (listeria, chlamydia) and some viruses
(herpes simplex, cytomegalovirus) can cause a miscarriage.
Radiation exposure: High levels of radiation (as used in treating
uterine cancer) usually induces a miscarriage in early pregnancies.
According to a number of Internet sources, lower levels, as in
diagnostic x-rays do, "...not increase the risk of miscarriage."
Lifestyle factors: The consumption of alcohol and smoking have been
associated with higher chances of miscarriage. In 1980, the U.S. Food and
Drug Administration issued a warning against the use of caffeine by pregnant women. Animal
studies had "linked caffeine to increased rates of birth defects, low birth
weight, stillbirths and miscarriage" in animals. A more recent study found that
even decaffeinated coffee influenced the miscarriage rate. It "found that women who
drank three or more cups of decaffeinated coffee a day in the first trimester had 2.4
times the risk of miscarriage as those who did not drink decaf." 2
||Medication: Specific drugs have been linked to increased chance of
Can abortions cause miscarriages?
It would seem that having a surgical abortion could scar a
small section of the wall of
the uterus and thus increase the chance of a subsequent miscarriage. The remaining potential
causes of miscarriages listed above appear to be unrelated to any prior abortion.
Eventually, almost all surgical abortions will probably be phased out, and replaced with:
These do not cause significant uterine wall damage. The chance of
any increased miscarriage rates should be eliminated.
How great is the increased risk of miscarriage after an abortion?
A series of 5 studies have been quoted by pro-life groups and published in numerous web
sites, scattered throughout the Internet. 3,4
||Levine et al.: This study was confined to "aggressively done
abortions," and is thus not representative of typical surgical abortions. They
found no increase in late abortions as a result of a single abortion. However, they found
a 2 to 3 times increase risk of first trimester miscarriages after two or more abortions. 5
Hilgers et al.: This describes a long term study on 52 women who had
had an abortion. Their their subsequent pregnancies were followed. Unfortunately, the
study is of little value because they did not include a control group of women who had not
had abortion. They did report a 27% miscarriage rate which is lower than average. 6
Kodasek: This is a 1971 Czechoslovakian study. It
refers to "cervical incompetence" causing the incidence of miscarriages
to reach 30 to 40%. This would represent an increase of miscarriage rate by about 4 percentage
points. This study was collected on women who had had late term abortions in which a
material called laminaria is used to dilate the cervix. Such abortions are rare in North
America; 90% of abortions are done during the first trimester and do not involve
laminaria. These data is not particularly useful. 7
Richardson & Dickson: This is a British study published in 1976
which showed that the miscarriage rate after an abortion was 17.5% when compared to 7.5%
for women who have not had an abortion. Unfortunately, these numbers appear quite
inaccurate. They do not agree with the average miscarriage rate, reported by
other researchers, of about 31%. Also, the study
was made only a few years after abortion was legalized in Britain. The
increase in miscarriage rates may well have been due to
back alley abortions. The results do not appear to have been
replicated by other studies. 8
||Koller & Eiklam: They reported that women who had had an abortion
on their first pregnancy had the "the highest frequency of late spontaneous
abortion and premature delivery." Unfortunately, the study is over 20 years old.
Results do not seem to have been replicated elsewhere.
Planned Parenthood® answers the question "Does an early abortion
make miscarriage more likely in future pregnancies?" with a simple "No."
There do not appear to be any convincing studies that would indicate that
have any significant link to increased miscarriage rate -- at least for the first
One study may point to an increased rate after multiple abortions.
There seems to be no evidence at all that emergency contraception or non-surgical
abortions increase the chances of later miscarriages.
Anthony R. Scialli, "Miscarriage: Executive Summary," at: http://c3.org/
The summary is based upon a report "Miscarriage" by the same author.
Article copies can be obtained from: Chlorine Chemistry Council, 1300 Wilson Boulevard,
Arlington, VA 22209. (703) 741-5829
Andy Evangelista, "Study of Caffeine and Miscarriage Yields Surprise Finding About
Decaf," 1997-AUG-25, at: http://www.ucsf.edu/
"Abortion: Questions & Answers," Ohio Right to Life, at: http://www.ohiolife.org/
"Maternal Complications," Catholic Information Center on Internet
™, at: http://www.catholic.net/
Levin et al., "Association of Induced Abortion with Subsequent Pregnancy Loss,"
JAMA, vol. 243, no. 24, June 27, 1980, pp. 2495-2499
Hilgers et al., "Fertility Problems Following an Aborted First Pregnancy."
In New Perspectives on Human Abortion, edited by S. Lembrych. University
Publications of America, 1981, pp. 128-134
A. Kodasek, "Artificial Termination of Pregnancy in Czechoslovakia," Internat'l
Jour. of GYN & OB, vol. 9, no. 3, 1971
Richardson & Dickson, "Effects of Legal Termination on Subsequent
Pregnancy," British Med. Jour., vol. 1, 1976, pp. 1303-4
Koller & Eikham, "Late Sequelae of Induced Abortion in Primagravida"
Acta OB-GYN Scand, 56 (1977) p. 311.
"Abortion: Commonly asked questions," Planned Parenthood®,
Copyright © 1998 to 2010, by Ontario
Consultants on Religious Tolerance
Latest update: 2010-JUN-23
Author: B.A. Robinson