Medical abortions increase risk of future pregnancy complications

Published: Jun. 30, 2009 at 6:54 PM CDT|Updated: Nov. 3, 2009 at 2:47 PM CST
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By Dr. Jai Ellis - email

Posted by, Jessica Boyd - email

A large study conducted in China has introduced a newfound concern regarding the safety of medical abortions.  This study of 9856 pregnant women is the first to have found an association between medical terminations and an increased likelihood of potentially lethal placental abnormalities and complications.

Terminations of pregnancy are placed into one of two categories.  They are either medical or surgical.

A surgical termination is one that involves the mechanical opening or dilatation of the cervix followed by the evacuation of the uterus. This usually employs a suction device and/or scraping mechanism, known as curettage.  The combination of the two components has been coined a D & C (for dilatation and curettage).  While a D & C can be performed for non-obstetric reasons, it is one of the most common methods used for abortions, especially prior to a gestational age of 14 weeks.  While there is no cutting or suturing performed, it is still an invasive procedure, which carries with it the risk of infection, hemorrhage, uterine perforation or anesthetic complications.  Potential future complications include:  uterine scarring with cessation of menses and placenta-previa (placenta covers all or part of the cervix) in a subsequent gestation.

The second method of termination is categorized as medical, as this does not employ a surgical component.  It generally involves the placement of a prostaglandin-containing drug into the vaginal vault.  Prostaglandins are mediators of inflammation within the immune system.  They have secondary effects on various organs, however.  Some prostaglandins cause relaxation of the uterus and will stop contractions and/or labor.  Others have an anti-thetical response to this and will cause the cervix to soften and dilate, as well as cause the uterus to contract.  When administered for prolonged periods of time, these agents can be used to induce labor and/or to terminate an early pregnancy.

In 1988, France and China became the first nations to approve the use of prostaglandin-containing drugs for first-trimester medical abortions.  They were believed to be safer than their surgical counterpart, as they were less invasive.  Risks attributed to them included infection, hemorrhage and uterine rupture.  The only significant placental complication cited was the risk of retained placental components which might require a D & C in order to empty the uterus.  Further, medical terminations were less costly and far more convenient, as they eliminated the need for an out-patient surgical procedure.

The study reviewed women at a number of clinics in Beijing, Shanghai and Chengdu from 1998 through 2001.  Women were eligible if they were aged 20-34, had not given birth previously, and had a history of no abortions or one Mifepristone (Prostaglandin E2)-induced abortion.  They were excluded if they had a history of severe heart, kidney, liver or lung disease.  Histories of tobacco, alcohol or drug use were reviewed and found to be rare and equal between the two groups.  Subjects with no previous pregnancy or abortion history were matched against subjects with a history of one previous Mifepristone-induced abortion.  They were followed at 28-30 weeks, at delivery and 4-6 weeks post-partum for placental complications in SUBSEQUENT pregnancies.

Placental complications were compared in the group that had not had a previous termination to the group that had undergone the prostaglandin-induced abortion.  There was no difference noted in placenta previa (placenta covering the cervix); placenta accreta (placenta imbedded in the uterine muscle) or retained placenta among these two groups.  However, there was a two-fold increase in the risk of placental abruption in the group which had undergone a previous medical abortion.

Placental abruption is the premature shearing away of the placenta from the uterine wall.  It separates PRIOR to delivery of the fetus and presents a sudden and severe risk of exsanguination  of both mother and fetus if delivery is not immediate.

The risk of abruption appeared to be heightened by: 1) a gestational age of more than 6 weeks; 2)  the previous termination being followed by D & C; 3) a longer inter-pregnancy interval.  This last finding is in stark contrast to the widely-held notion that a short time interval between pregnancies is likely to increase abruption risk.

This study carries great weight, not only for its subject matter, but also for its country of origin.  An American study of this nature might fall under criticism and suggestion that the test subjects might under-report previous abortions that would increase their risk, due to the controversial nature of abortions in America.  The authors of this article are quick to point out that this sort of bias is much less likely to occur in China, as the prevailing climate about abortion is much less heated.  In China, abortion is an acceptable and widely-used medical modality and, therefore, the subjects would have no reason to over- or under-report their histories.

It is important, as with any medical procedure, that the patient is aware of all potential risks and benefits.  Only then can they make the decision that is best for them.  Until now, medical terminations were considered relatively free of risk compared to the surgical alternative.  While immediate side effects of the medical termination are less severe, it is imperative that women and their Obstetricians are aware of any risk factors that might increase the risk associated with a subsequent pregnancy.  Not only might it impact a woman's decision regarding whether or not to terminate a pregnancy, but it might influence her choice of methods, if she is inclined to decide this.  It might also enable her provider to act swiftly and pre-emotively should signs or symptoms of abruption present during a future gestation.