GENEVA — In an advance with widespread social implications, researchers now believe that drug-induced non-surgical abortions can be made widely available during the first trimester of pregnancy.
The experimental treatment, which involves the sequential administration of two medicines, is producing a 95% success rate, with few side effects, according to a recently completed progress report by a World Health Organization task force.
This success rate is comparable to that achieved with surgical abortions but avoids potential complications such as anesthesia, infection and psychological trauma.
The combination therapy could provide an alternative to many of the 40 to 50 million surgical abortions performed worldwide each year, as well as dramatically lower the costs of abortions during the first three months of pregnancy.
It may also allow some patients to take the medicines while continuing their normal activities, according to the report by WHO's task force on "post-ovulatory methods for fertility regulation."
Controversy May Intensify
"You should be able in a couple of years to have a medical abortion that is equally effective to a surgical abortion," Dr. Jose Barzelatto, director of the WHO human reproduction research program, said in an interview here. "It means no invasion of privacy and no surgical risk."
Such apparent benefits aside, fertility researchers are concerned that their work will intensify the controversy in many nations about the circumstances in which women should be permitted to have abortions.
"The whole debate on abortion is going to be revived with this drug," Barzelatto acknowledged.
The conclusion of the task force, made up of international experts, is based on a review of clinical studies from Britain, China, France and Sweden involving more than 500 pregnancy terminations with the combination therapy. The drug-induced abortions are also being evaluated in ongoing WHO-sponsored studies involving 11 countries and about 700 women.
One of the two medicines in the combination therapy is the much-heralded experimental French abortion "pill," RU 486. It works by blocking the action of the sex hormone progesterone, which is necessary for the development of the fetus and its attachment to the uterus.
When taken within days of a missed menstrual period, RU 486 can cause the uterus to expel the fertilized egg in about 85% of cases, according to a December, 1986, report in the New England Journal of Medicine.
In that French study, the drug induced uterine bleeding in all 100 women who were seeking abortions. They were treated with various doses of the drug within 10 days of missing a menstrual period. The bleeding continued for an average of 11.6 days. But follow-up studies confirmed expulsion of the developing embryo in only 85% of the patients; the others required surgical abortions.
The other medicine is a low dose of one of several less-publicized compounds that can also terminate pregnancy, called prostaglandins. They work by stimulating the uterus to contract, which in turn can expel the fertilized egg. They can be taken as pills, shots or vaginal suppositories and are sold by prescription in many countries.
High doses of prostaglandins are up to 95% effective in triggering abortions during the first trimester of pregnancy, Barzelatto said. But they often cause severe side-effects, such as nausea and abdominal cramping. These side-effects can be avoided with the low doses of prostaglandin used in the combination therapy, according to the task force report.
Researchers have combined the two therapies by giving a dose of RU 486, followed by a prostaglandin about two days later.
This approach appears to avoid the chief problems which can develop when either medicine is used alone, Barzelatto said.
RU 486, for example, is most effective in the first six weeks of pregnancy--before many women either realize they are pregnant or seek medical attention for possible abortion.
The drug has a high failure rate of up to 40% when used after the first six weeks of pregnancy, according to Barzelatto. The heavy bleeding, which can occur when it is used alone, apparently can be avoided through the combination therapy.
The manufacturer of RU 486, Roussel-UCLAF of Paris, is seeking marketing approval of the drug as a prescription medicine in France. Despite ongoing tests in the United States, including at USC in Los Angeles and at the University of California, San Diego, the manufacturer has not announced plans to seek similar approval in the United States, largely because of the anticipated objections from anti-abortion groups.
Since RU 486 was first synthesized in the early 1980s, a series of similar drugs have been created in the laboratory. For example, a drug manufactured by Schering-Berlin in West Germany appears to be equally effective in preliminary tests, according to Barzelatto.
RU-486 and prostaglandins differ from the so-called morning-after pills, which are effective in terminating possible pregnancy only if taken within 72 hours of sexual intercourse, although research is in progress to see if RU-486 can be effectively used in this fashion as well.
Current morning-after pills are usually nothing more than large doses of birth control pills, and they work by interfering with the initial attachment of the fertilized egg to the uterus.