Last week the government approved Seasonale, a contraceptive pill that reduces a woman’s menstrual periods to just four a year. While a new pill regimen, the drug is based on the same technology that led to the first oral contraceptives four decades ago. Hormonal methods, along with barriers like condoms, have ruled the product market ever since. But scientists are hoping to one day offer radically new methods as they set their sights on the genetics of fertility.
As researchers discover which genes are involved in fertility and just how they function, they are uncovering potential ways to interfere with those genes or the proteins they produce.
“Modern molecular biology is going to generate insights and ultimately will lead to approaches we can’t even imagine at the moment,” says Henry Gabelnick, director of CONRAD, a contraceptive development group that is affiliated with Eastern Virginia Medical School.
Several methods of birth control are currently available, including pills, patches, implants, injections, vaginal rings, IUDs, male and female condoms and sterilization. So why the need for new methods?
“Fifty percent of pregnancies in the United States each year are unplanned, so something’s not working right,” says Gabelnick.
People need a variety of effective and convenient choices, says Lawrence Finer, assistant director of research at the Alan Guttmacher Institute, a nonprofit group in New York City that focuses on sexual and reproductive health research and education.
“There are both physical and personal reasons that different people need different methods,” Finer says, “and that a single person will need different methods at different points in life.”
No perfect method
And though current methods can be highly effective if used properly, there’s room for improvement, experts say.
In addition, side effects of hormonal methods are a concern. The pill, for instance, may slightly raise the risk of blood clots, particularly for smokers, and cause discomforts like nausea and headache. And men only have two choices of birth control: condoms and vasectomy.
“There is still a tremendous need for new contraceptives even though effective methods exist,” says Dr. Jerome Strauss III, director of the Center for Research on Reproduction and Women’s Health at the University of Pennsylvania Medical Center in Philadelphia.
“It’s now clear to many in the field that there is not one perfect contraceptive,” he says.
Strauss is chairing a committee organized by the Institute of Medicine, an independent research arm of the National Academy of Sciences, that has been meeting over the last several months to discuss future directions in contraceptive research.
The last meeting ended Tuesday in Wood’s Hole, Mass., and the group is planning to release a report early next year with recommendations for contraceptive development.
New targets
Among the possible approaches the group has been discussing are methods that would target specific genes or proteins. The hope is that such high-tech approaches would be more effective than current methods and have fewer, if any, side effects.
Possibilities include techniques that would:
Allow an egg to block sperm penetration, perhaps by disabling proteins on the surface of the egg that allow the sperm to enter.
Prevent sperm from maturing and being able to fertilize an egg. “There are a number of places where one can interfere with the development of sperm that might lead to infertility,” Gabelnick says. Dr. Regine Sitruk-Ware, executive director of product development at the nonprofit Population Council in New York City, is working to develop a pill that would inhibit a specific protein involved in sperm maturation. The goal is to create a male method that would be easily reversible.
Prevent sperm from traveling up through the uterus to the fallopian tubes, where fertilization occurs. One approach, perhaps in the form of a pill, implant or vaginal ring, might interfere with proteins in the uterus that normally promote the upward flow of sperm, says Sitruk-Ware.
Prevent a fertilized egg from implanting in the uterine lining, an approach that would likely be met with controversy.
Inhibit egg release. Such an approach might target certain genes that allow an egg to escape from an egg follicle in the ovaries. If the egg is never released, it can’t be fertilized.
'A very ambitious goal'
So far, all of this research is still in the lab, with some animal experiments offering encouraging results. But it will be years — at least a decade or more — before any of these methods might be available to the public, researchers predict.
“It’s a very ambitious goal,” Sitruk-Ware says.
And just how quickly they become available will depend greatly on funding from the government, private organizations and pharmaceutical companies. But contraceptive research isn’t a red-hot area of R&D like cancer, heart disease or Alzheimer’s.
Strauss hopes the release of the IOM report will help change that.
“We are anxious to have a revival of interest in contraception,” he says.
Strauss notes that the industry is still smarting from lawsuits against the makers of the Dalkon Shield IUD, which was taken off the market after being associated with infections and even some deaths, and Norplant, which was linked with side effects that users say they weren’t properly warned about.
“These are lessons that have not been forgotten,” he says.