September 14, 2012 (Mercatornet.com) - In a study published last week in the European Journal of Public Health, Priscilla Coleman and colleagues report that mothers who have experienced natural pregnancy loss or induced abortion are more likely to die over a 25-year period than those who have experienced only giving birth. Dr Coleman, a Professor of Human Development and Family Studies at Bowling Green State University, responds here to MercatorNet’s questions about the study.

What was your aim in this study?

The study was undertaken to provide reliable data pertaining to the relative risk of death associated with distinct reproductive history patterns over many years. Acquiring and disseminating accurate data pertaining to maternal mortality have been longstanding global concerns. Inconsistent definitions regarding what constitutes a maternal death and incomplete data confined to very brief time periods have left society largely in the dark regarding true mortality risks associated with pregnancy generally and with particular outcomes, both immediately after pregnancy resolution and across the years that follow.

Regarding the data problem, the World Health Organization has noted: “Maternal deaths are hard to identify because this requires information about deaths among women of reproductive age, pregnancy status at or near the time of death, and the medical cause of death. All three components can be difficult to measure accurately.”

Most existing statistics rely upon death certificates to estimate maternal mortality and as noted by Gissler and colleagues in 2004, without data linkage to complete pregnancy and abortion records, 73% of all pregnancy associated deaths could not be identified from death certificates alone. Large population-based record-linkage studies, containing complete reproductive history data and data related to deaths, provide a unique opportunity to bypass many of the limitations of the currently available maternal mortality data in most countries. Our study was this type of study.

In a nutshell, what did it show about pregnancy loss compared with giving birth?

Pregnancy loss, whether due to induced abortion or natural loss (miscarriage or stillbirth), was associated with a higher probability of dying over the 25 year study period when compared to giving birth. However, the results related to natural loss should be interpreted cautiously, because only the most serious cases requiring hospitalization are captured in the data.

Are the results robust compared with other studies on this subject?

The results are comparable to other record-based studies. In a record-based study by Reardon and colleagues, U.S. women who aborted, when compared to women who delivered, were 62% more likely to die over an 8 year period from any cause after adjustments were made for age. Further, consistent findings were reported in large Finnish population-based studies by Gissler and colleagues published in 1997 and in 2004.

In the first study, post-pregnancy death rates within 1 year were reported to be nearly 4 times greater among women who had an induced abortion (100.5 per 100,000) compared to women who carried to term (26.7 per 100,000). Spontaneous abortion had a pregnancy associated mortality rate of 47.8 per 100,000. In the later study, Gissler and colleagues again found that mortality was significantly lower after a birth (28.2 per 100,000) than after a spontaneous abortion (51.9 per 100,000) and following an induced abortion (83.1 per 100,000).

Our results then are consistent with prior work and extend what is known by examining combinations of different reproductive outcomes and by examining the associations between repeated experiences of the same outcome in association with mortality risk.

What, specifically, did your study show about the risk or benefit of a) induced abortion, b) miscarriages and stillbirths, c) births only?

With controls for the number of pregnancies, year of birth, and age at last pregnancy, when compared to only giving birth, having only induced abortion(s) was associated with a 66% increased risk of dying. A reproductive history entailing only natural losses (compared to birth) was associated with a 181% increased risk of dying across the study period.

Did it make any difference how often a woman experienced abortion, miscarriage etc, or the birth of child?—or what combination of these different outcomes she experienced?

Yes, both things made a difference. Women who had experienced both induced abortion and natural loss were, on average, more than three times (327%) more likely to die over the 25-year period. When induced abortion and birth were combined, the risk of dying was increased by 56%. Natural loss in conjunction with birth was associated with a 29% increased mortality risk. When all reproductive outcomes were present in women’s lives, when compared to only birth(s), a 94% increased risk of death was observed. Risk of death was over 6 times greater among women who had never been pregnant compared to those in the birth(s) only group.

Multiple abortions, compared to no experience of abortion, and after applying controls, increased the risk of mortality as follows: one abortion, 45%; two abortions, 114%; three abortions, 191%. Similarly, increased risks of death were equal to 44%, 86%, and 150% for one, two, and three natural losses respectively compared to no natural losses.

By contrast, giving birth to more than one child significantly decreased mortality risks. Specifically, two births were associated with an 83% lower risk of death compared to no births, three or more births corresponded to a 44% decreased risk over no births.

Early this year a US study reported that women were about 14 times more likely to die during or after giving birth to a live baby than to die from complications of an abortion—and it received a lot of attention. But your study suggests that birth is protective of the life of mothers compared to abortion. How do you explain the difference?

In arriving at their conclusion that abortion is many times safer than childbirth, Raymond and Grimes relied on data from the Center for Disease Control (CDC) to secure numbers of deaths related to childbirth and induced abortion. The authors acknowledged underreporting, but they made no attempt to address the factors associated with this shortcoming, nor did they discuss the magnitude of the problem: “Weaknesses include the likely under-reporting of deaths, possibly         differential by pregnancy outcome (abortion or childbirth.)”

Raymond and Grimes also failed to address abortion-related deaths beyond the first trimester, which constitute 12-13% of all abortions performed in the US. Using national U.S. data spanning the years from 1988 to 1997, Bartlett and colleagues reported the relative risk of mortality was 14.7 per 100,000 at 13–15 weeks of gestation, 29.5 at 16-20 weeks, and 76.6 at or after 21 weeks.

Although your study does not establish causality, do you have any theories about how pregnancy loss would shorten women’s lives—other than through immediate complications of the abortion or miscarriage?

As a psychologist without medical training, any hypotheses that I have are largely restricted to mediational processes involving mental health variables. There is significant evidence that an abortion experience increases a woman’s risk for experiencing mental health problems and when women are anxious, depressed, or abusing substances, they are more prone to experiencing accidents, negative partner relationships, and suicide, and their overall physical health may decline rendering them more susceptible to chronic and acute physical ailments.

One result in your study seems surprising—the greatly elevated risks of death among women who had not experienced any pregnancies. What do you make of that?

Without inclusion of additional demographic data, health history, and cause of death information, I think it would be premature to speculate too much. There is a great deal of medical research demonstrating physical and psychological benefits of full-term pregnancy, so women who have not experienced a pregnancy will not benefit from them. Moreover, many women in our Danish study may have died before they had opportunity to experience a pregnancy.

What further research would you like to do—or see done—on this subject?

My primary research interests relate to mental health correlates of reproductive outcomes; therefore in the future, I would like to more closely examine specific psychological pathways leading from distinct reproductive outcomes to particular causes of death using record-based data.

More specifically, I would really like to see if women who have experienced induced abortion are more likely to die from causes that may be logically associated with adverse mental health outcomes such as suicide, deaths due to engagement in risk-taking behaviors, and/ or substance abuse. 

In this regard, there are a few existing record-based studies that have addressed associations between particular reproductive outcomes and chance of death due to suicide. For example, in a population-based study, Appleby (1991) reported in the British Medical Journal that pregnant women are 1/20th as likely to commit suicide when compared to non-pregnant women of childbearing age. Appleby concluded that “Motherhood seems to protect against suicide.”

Further, Gissler and colleagues (2005) reported the annual suicide rate for women of reproductive age to be 11.3 per 100,000; whereas the rate was only 5.9 per 100,000 in association with birth (and was a startling 34.7 per 100,000 following abortion). Several other studies conducted in various countries have revealed low rates of suicide in the year following birth when compared to non-postpartum samples.

When your study showing a link between abortion and mental health problems was published a year ago in the British Journal of Psychiatry you were severely criticized by peers. Have you been attacked for these latest findings that show abortion in an unfavourable light?

Not that I am aware of. But I honestly don’t pay too much attention to what is said about me, beyond defending the rigor of the studies and the quality of the journals so that the results will be taken seriously and used to inform women and health care professionals. The satisfaction that comes from helping women to be heard far outweighs any slanderous comments about me that are floating around.

Priscilla K. Coleman is a Professor of Human Development and Family Studies at Bowling Green State University in Ohio. Dr Coleman has nearly 50 peer-reviewed journal articles published, including 33 on abortion and mental health. In recognition of her strong publication record, she has been called to serve as an expert in several state and civil court cases, has spoken at the UN, and in 2007 she testified before U.S. Congress. Dr. Coleman is currently on the editorial boards for five international psychology and medical journals.

Study citation: Coleman, P. K., & Reardon, D. C. (September, 2012) “Reproductive History Patterns and Long-Term Mortality Rates: A Danish, Population Based Record Linkage Study”. European Journal of Public Health.

Michael Cook is editor of MercatorNet. This article reprinted under a Creative Commons License.