Around eighty-percent of all women in the U.S. will take birth control at some point in their lives, but the burden of taking “the pill” could soon no longer rest on women’s shoulders alone.
For many women, taking the pill is part of their daily routine, and many women often start on birth control as teenagers. Researchers are now working on creating a type of birth control for men, but they have the difficult task of overcoming men’s production of a thousand sperm a second. In order for a male contraceptive to be effective, sperm count has to go down to zero.
Michael Lehmann has been involved in five testosterone-based clinical trials. He’s taken daily pills, monthly injections, rubbed a cream on his shoulder and even had an implant.
"There were very minor side effects, um, I had some slight acne on my scalp,” Michael said about his involvement in the trials.
Testosterone could increase the risk of heart disease and prostate cancer, which is why Dr. John Amory is blocking vitamin A in the testis, which in turn blocks the development of sperm.
Dr. Amory is a professor of medicine at the University of Washington School of Medicine, and says “I decided to explore ways of suppressing sperm without using hormones.”
Tests conducted on mice show that it works 100-percent of the time, but some doctors like Dr. Sanjay Acerwall a reproductive endocrinologist at UC San Diego, are skeptical.
“A male contraceptive, I don’t think women will trust it,” Dr. Acerwall said laughing.
While it may take time for men to warm up to the idea of male birth control, choosing when to have or not have a baby could be in their hands.
Researchers have also found a hormone-free way to make the testicles “forget” how to make sperm. A drug that targets a protein that is critical for sperm production is currently being tested, those working on the project say it is reversible. When mice were taken off the treatment they became fertile once again.
BACKGROUND: Half of pregnancies in the United States are unintended. However, there are several effective methods of contraception available. Since the year 2000, there have been many new methods of birth control in the U.S., including the levonorgestrel-releasing intrauterine system, the hormonal contraceptive ring, the patch, the 91-day regimen of oral contraceptives, the hormonal implant, and a new form of female sterilization. The most popular method used by over ten million women in the US between 2006 and 2008, was the oral contraceptive pill. (Source: www.cdc.gov) However, male contraception is becoming more popular.
INTERESTING FACTS ABOUT CONTRACEPTION: Between 2006 and 2008, 99% of women who had ever had sexual intercourse had used at least one method of birth control. Some interesting facts are:
* 7.3% of women who were currently at risk of unintended pregnancy were not using a contraceptive method.
* Hormonal implants for women are 99% effective.
* Injections for women are 91-99% effective.
* Both the pill and the patch for women are 91-99% effective.
* Male condoms are 82-98% effective. Female condoms are 79-95% effective.
* Spermicides are 72-85% effective.
* Female sterilization, trans cervical sterilization, and male sterilization are all over 99% effective. (Source: www.cdc.gov)
TYPES OF MALE CONTRACEPTION: The two most common male contraceptive methods are vasectomies and condoms. They have obvious draw backs (not being reversible and condoms have a high failure rate). A study found that over 60% of men in Spain, Brazil, Mexico, and Germany were willing to use a new method of male contraception. A heat-based method could offer easily implemented birth control. Researchers have used different sources of heat to disrupt fertility: hot water, incandescent light bulbs, saunas, and ultrasounds. Optimal sperm production (spermatogenesis) requires temperatures to be below average body temperature. By warming the testicles above average, it disrupts spermatogenesis. RISUG is an option that is effective immediately right after injection procedures and lasts for ten years unless reversed. (Source: www.malecontraceptives.org)
NEW TECHNOLOGY: Oral contraceptives have been available for women since the 1960s, but for men this option has been limited. Some have tried using testosterone to decrease sperm production, but they come with a list of side effects (acne, increase risk of heart disease and prostate cancer). Spermatogenesis relies on vitamin A to allow the production of normal numbers of sperm. Researchers are developing a way to use vitamin A metabolism in the testis to regulate spermatogenesis. One recent study found that a compound that interferes with the body's ability to use vitamin A made male mice sterile (they were receiving 8 to 16 week courses). Once they stopped giving it to the mice, they resumed making sperm. So far, the researchers have not found side effects and testosterone remained stable. Another study is working with a drug that interferes with the action of an enzyme that converts vitamin A to its biologically active form in the testis, hoping it will render men temporarily sterile. Testing is still under way. (Source: www.ncbi.nlm.nih.gov)
Bottom of Form
FOR MORE INFORMATION, PLEASE CONTACT:
John K. Amory, MD, MPH
University of Washington