Long-acting contraceptives are the most effective
Ingrid Skop, For the Express-News Published 12:00 am, Sunday, October 8, 2017
As an obstetrician/gynecologist, I followed with interest the discussion surrounding the San Antonio City Council’s decision to provide funding for long-acting reversible contraception, or LARCs, for teenagers at risk of unintended pregnancy.
We all want what is best for our teens’ emotional and physical health. Abstinence should be encouraged, because it is the only completely effective way to prevent pregnancy, avoid sexually transmitted infections, and escape the emotional consequences that may come with early sexual behavior.
Yet, we should be aware that most young women do become sexually active during high school. Three out of 10 American women become pregnant by age 20. Half of all U.S. pregnancies (about 3 million a year) are unintended, and almost half of all unintended pregnancies are aborted.
Unfortunately, many commonly used birth control methods are not very reliable, often because they are used inconsistently. In fact, about half of unintended pregnancies occur when a woman is using some method of contraception.
If no contraception is used, there is an 85 percent likelihood of pregnancy within a year. Failure of condoms and other barrier methods ranges from 18 percent to 30 percent. User-dependent hormonal contraceptives (pills, patch and vaginal ring) have a failure rate of 9 percent in adult women and 13 percent in teenagers with typical use. Even the contraceptive shot has a failure rate of 6 percent.
For teenagers who choose to become sexually active, we should encourage the most effective methods to prevent unintended pregnancies. Unlike user-dependent methods, long-acting reversible contraceptives (intrauterine devices or IUDs, and subdermal implants) do not depend on the user’s actions to be effective. Their failure rate is extremely low (0.5-3 out of 1,000). Large studies have shown that their use reduces the incidence of unintended pregnancies and abortions by up to 40 percent.
Unfortunately, LARCs have been subject to rumors about their safety and the false assumption that their mechanism of action is abortion-inducing.
Subdermal implants (which last three years) work by secreting progesterone into the bloodstream, which prevents release of an egg, and they create a mechanical barrier to the uterus.
Levonorgestrel IUDs (which last three to five years) release progesterone locally and also form a mechanical barrier.
The nonhormonal, copper IUD (which lasts 10 years) has a toxic effect on sperm, destroying them long before they can fertilize an egg.
We know that these devices work to prevent fertilization, because if they did not and an embryo was formed, progesterone would slow the embryo’s movement through the tubes and result in frequent tubal pregnancies. Yet we rarely see tubal pregnancies in women using LARCs. This confirms the mechanism of action occurs before an egg is fertilized, not by disrupting the implantation of an embryo.
The risks associated with these devices are far less than often assumed. They do not cause cancer or infertility, they can treat abnormal uterine bleeding, and they are safe for women who do not tolerate estrogen. The risk of pelvic inflammatory disease and damage to the uterus is less than 1 percent. The American College of Obstetrics and Gynecology recommends them as a first-line contraceptive for teenagers, because they work so well to prevent unintended pregnancies.
While we hope that teens postpone sexual activity until they are more mature, this is not the reality for many. Those on both sides of the abortion debate agree that it would be far better if unintended pregnancies did not occur so that abortion would not need to be considered.
Let us help all sexually active teens have access to safe and reliable birth control methods, such as LARCs. These methods do not cause abortions. They prevent them.
Ingrid Skop is a physician and a board member of Healthy Futures, which works to decrease births to teens, and of The Contraceptive Initiative, founded to promote the use of LARCs.