Health Effects

Early-term surgical abortion is a simple procedure, and when performed by competent doctors (and in some states, nurse practitioners, nurse midwives and physician assistants) in first-world nations (before the 16th week), is safer than carrying the pregnancy to term.

As with most surgical procedures, the most common surgical abortion methods carry the risk of potentially serious complications. These risks include: a perforated uterus, perforated bowel or bladder, septic shock, sterility, and death. The risk of complications occurring can increase depending on how far the pregnancy has progressed, but may be counterbalanced by complications that would occur from carrying the pregnancy to term.

It is difficult to accurately assess the risks of induced abortion due to a number of factors. Firstly, there are relative health risk of induced abortion and pregnancy, which are both affected by wide variation in the quality of health services in different societies and among different socio-economic groups, a lack of uniform definitions of terms, and difficulties in patient follow-up and after-care. The degree of risk is also dependent upon the skill and experience of the practitioner; maternal age, health, and parity; gestational age; pre-existing conditions; methods and instruments used; medications used; the skill and experience of those assisting the practitioner; and the quality of recovery and follow-up care. A highly-skilled practitioner of birth and abortion, operating under ideal conditions, will tend to have a low rate of complications; an inexperienced practitioner in an ill-equipped and ill-staffed facility, on the other hand, will often have a higher incidence of complications and could prove fatal in both case of pregnancy and abortion.

In the United Kingdom, the number of deaths due to legal abortion between the years of 1991 and 1993 was 5, as compared to the 9 deaths caused by ectopic pregnancy during the same time frame. In the United States, during the year 1999, there were a total of 4 deaths due to legal abortion.

Some practitioners advocate using minimal anesthesia so that the patient can alert them to possible complications. Others recommend general anesthesia, in order to prevent patient movement, which might cause a perforation. General anesthesia carries its own risks, including death, which is why public health officials recommend against its routine use.

Dilation of the cervix carries the risk of cervical tears or perforations, including small tears that might not be apparent and might cause cervical incompetence in future pregnancies. Most practitioners recommend using the smallest possible dilators, and using osmotic rather than mechanical dilators after the first trimester of pregnancy.

Instruments are placed within the uterus to remove the fetus. These can, on rare occasions, cause perforation or laceration of the uterus, and damage to structures surrounding the uterus. Laceration or perforation of the uterus or cervix can, again on rare occasions, lead to even more serious complications.

Incomplete emptying of the uterus can cause hemorrhage and infection. Use of ultrasound verification of the location and duration of the pregnancy prior to abortion, with immediate follow-up of patients reporting continuing pregnancy symptoms after the procedure, will virtually eliminate this risk. The sooner a complication is noted and properly treated, the lower the risk of permanent injury or death.

In rare cases, the abortion will be unsuccessful and the pregnancy will continue. An unsuccessful abortion can also result in the delivery of a live neonate, or infant. This, termed a failed abortion, is more likely to occur if the procedure is carried out later in the pregnancy. Some doctors faced with this situation have voiced concerns about the ethical and legal ramifications of then letting the neonate die. As a result, recent investigations have been launched in the United Kingdom by the Confidential Enquiry into Maternal and Child Health (CEMACH) and the Royal College of Obstetricians and Gynecologists, in order to determine how widespread the problem is and what an ethical response in the treatment of the infant might be.

Use of other methods (e.g., overdose of various drugs, insertion of various objects into uterus) for abortion is potentially dangerous, carrying a significantly elevated risk for permanent injury or death compared to abortions done by physicians.

Suggested effects

There is controversy over a number of proposed risks and effects of abortion. Evidence, whether in support of or against such claims, might in part be influenced by the political and religious beliefs of the parties behind it.

Breast cancer

The abortion breast cancer (ABC) hypothesis posits a causal relationship between having an induced abortion and a higher risk of developing breast cancer in the future. An increased level of estrogen in early pregnancy helps to initiate cellular differentiation and growth in the breast in preparation for lactation. If this process is terminated, through abortion, before full differentiation in the third trimester, then more "vulnerable" undifferentiated cells will be left than there were prior to the pregnancy. It is proposed that this might result in an elevated risk of breast cancer. The majority of interview-based studies have indicated a link, and some have been demonstrated to be statistically significant, but there remains debate as to their reliability because of possible response bias.

Larger and more recent record-based studies, such as one in 1997 which used data from two national registries in Denmark, found the correlation to be negligible to non-existent after statistical adjustment. The National Cancer Institute conducted an official workshop with dozens of experts on the issue in February 2003, which concluded from its examination of various evidence that it is "well established" that "induced abortion is not associated with an increase in breast cancer risk." These findings and how the Denmark study statistically adjusted their overall results have been disputed by Dr. Joel Brind, an invitee to the workshop and the leading scientific advocate of the abortion-breast cancer hypothesis. Nevertheless, gaps and inconsistencies remain in the research, and the subject continues to be one of political and scientific contention.

Fetal pain

The existence or absence of fetal sensation during abortion is a matter of medical, ethical and public policy interest. Evidence is conflicting, with some authorities holding that the fetus is capable of feeling pain from the first trimester, and others maintaining that the neuro-anatomical requirements for such experience do not exist until the second or third trimester.

Pain receptors begin to appear in the seventh week of pregnancy. The thalamus, the part of the brain which receives signals from the nervous system and then relays them to the cerebral cortex, starts to form in the fifth week. However, other anatomical structures involved in the nociceptic process are not present until much later in gestation. Links between the thalamus and cerebral cortex aren't forged until around the 23rd week.

Researchers have observed changes in the heart rates and hormonal levels of newborn infants after circumcision, blood tests, and surgery — effects which were alleviated with the administration of anesthesia. Others suggest that the human experience of pain, being more than just physiological, cannot be measured in such reflexive responses.

Mental health

Some women will experience negative feelings as a result of elective abortion. However, whether this phenomenon is significant enough to warrant a general diagnosis, or even classification as an independent syndrome (see post-abortion syndrome), is a subject that is debated among members of the medical community.

Data on the incidence of clinical depression, mental illness, post-traumatic stress disorder, and suicide in association with abortion remain inconclusive. A comparative analysis of the suicide rates among postpartum and post-abortive women in Finland found a statistical correlation between abortion and suicide.

Other studies have suggested a link between the elective termination of an unwanted pregnancy and an improvement in reported mental well-being. Elective abortion may reduce the occurrence of depression in cases of unwanted pregnancy, as compared to cases in which the pregnancy has been carried to completion, but it is also sometimes reported as an additional stressor (ibid.). The majority of evidence would seem to indicate that adverse emotional reactions to the procedure are most strongly influenced by pre-existing psychological conditions and other negative factors (ibid.).

Spontaneous abortion, or miscarriage, is known to present an increased risk of depression in women.