After ‘Roe’, contraceptive failures carried an even bigger blow

Birth control options have improved over the decades. Oral contraceptives are now safer, with fewer side effects. Intrauterine devices can prevent pregnancy 99.6% of the time. But no prescription drug or medical device works flawlessly, and human contraception isn’t perfect.

“No one walks into my office and says, ‘I’m planning to miss a pill,'” says obstetrician-gynecologist Dr. Mitchell Kreinin.

“There’s no such thing as perfect use, we’re all real-life users,” said Crinin, a professor at the University of California-Davis who wrote a widely used textbook that details contraceptive failure rates.

Even when the probability of contraceptive failure is small, the number of incidents can increase rapidly. With more than 47 million women of reproductive age in the United States using contraception and relying on birth control methods, hundreds of thousands of unplanned pregnancies may occur each year. With most abortions banned in at least 13 states and legal battles underway in others, contraceptive failure now poses a major risk to millions of Americans.

Researchers distinguish between perfect use of birth control, when a method is used consistently and correctly every time, and typical use, when a method is used in real-life situations. No birth control, other than total female sterilization, has a failure rate of 0.00%.

The failure rate for the common use of birth control pills is 7%. For every million women who take the pill, 70,000 unplanned pregnancies occur in a year. According to the most recent data, more than 6.5 million women between the ages of 15 and 49 use oral contraceptives, resulting in approximately 460,000 unplanned pregnancies.

A chart title, "The common use failure rate for birth control pills is 7%.".  A subtitle reads, "7 out of 100 women may experience pregnancy during the first year of taking the pill." Below the text are 100 stick figures, 7 of which are highlighted in orange.  Below the statistics is written, "Of the approximately 6,580,000 women taking the pill, 460,000 unplanned pregnancies may occur."
(Emma Lee Gomez/Science Friday)

Even the apparent failure rates of IUDs and birth control implants can be surprising.

An intrauterine device releases a hormone that thickens the mucus on the uterus. Sperm hit the brick wall of the mucus and are unable to cross the barrier. The implant is a matchstick-sized plastic rod placed under the skin, which sends a steady, low-dose hormone into the body that thickens the cervical mucus and prevents the ovaries from releasing an egg. But not all the time. Hormonal IUDs and implants fail to prevent pregnancy 0.1% to 0.4% of the time.

About 4.8 million women in the United States use IUDs or implants, resulting in 5,000 to 20,000 unplanned pregnancies a year.

“We’ve had women come in for abortions who had IUDs, and they were one in a thousand,” said Gordon Lowe, a nurse practitioner at Planned Parenthood in Little Rock.

Dr. Janet Cathey (left) and Gordon Lowe, a nurse practitioner, work at Planned Parenthood in Little Rock, Arkansas. Republican Gov. Asa Hutchinson kicked Planned Parenthood out of Medicaid in 2017, leaving patients unable to get free contraception at clinics.(Sarah Varney/KHN)

Abortion has been banned in Arkansas since the Supreme Court ruling Dobbs v. Jackson Women’s Health Organization At the end of June. The only exception is when the patient’s death is considered imminent.

These curves are the new background for couples to decide which type of contraceptive to choose or to calculate their chances of conception.

Another complication is the belief among many that contraception should work all the time, every time.

“In medicine, there’s no such thing as 100%,” says Dr. Regine Sitruk-Ware, a reproductive endocrinologist at the Population Council, a nonprofit research organization.

All sorts of factors interfere with contraceptive effectiveness, Sitruk-Ware says. Certain medications and herbal supplements for HIV and tuberculosis can interfere with the processing of St. John’s Wort birth control pills in the liver. A healthcare provider may accidentally insert an IUD into the uterus. Emergency contraception, including Plan B, is less effective in women who weigh more than 165 pounds because the drug’s hormones are weight-dependent.

And life is busy.

“You may be late taking your next pill,” says Sitruk-Ware, or going to the doctor to have “your next vaginal ring” inserted.

Using contraception consistently and correctly reduces the chance of failure, but Alina Salganikoff, director of women’s health policy at KFF, says access to birth control is anything but reliable for many people. Birth control pills are needed for months, even years, but “most women can only get a one- to two-month supply,” she said.

Even vasectomy can fail.

During a vasectomy, the surgeon cuts the tube that carries sperm into the semen.

The method is one of the most effective methods of birth control – with a failure rate of 0.15% – and avoids the side effects of hormonal birth control. But even after cutting the vas deferens, the body’s cells can still heal themselves after a vasectomy.

“If you cut your finger, the skin covers it,” Crinin said. “Depending on how big the gap is and how the procedure is done, that tube can grow back together, and that’s one of the ways it can fail.”

Researchers are testing a reversible birth control method for men, which involves applying a hormonal gel to the armpit that suppresses sperm production. Among the 350 participants and their partners in the trial, zero pregnancies have occurred so far. The new method is expected to take several years to reach the market and become available to consumers. Meanwhile, vasectomy and condoms are the only contraception available to men, who are fertile most of their lives.

At 13%, the condom’s general-use failure rate is the highest among birth control methods. Condoms play an important role in stopping the spread of HIV and other sexually transmitted infections, but they are often misused or torn. A typical-use failure rate means that for 1 million couples using condoms, 130,000 unplanned pregnancies can occur in a year.

A chart title, "Estimated number of unplanned pregnancies with birth control methods during the first year of use." It displays the dots for the four birth control methods with the size of the dots proportional to how many unintended pregnancies may occur  The largest dot represents the male condom, with 513,000 expected pregnancies.  The second largest represents birth control pills, with 460,000 pregnancies.  The third largest represents users of Depo-Provera, the contraceptive ring, or patch, with 102,000 pregnancies.  The smallest dot represents the IUD or implant, which causes 5,000 to 20,000 pregnancies.
(Emma Lee Gomez/Science Friday)

Navigating the failure rate of birth control drugs and medical devices is only one aspect of pregnancy prevention. Convincing a male sexual partner to use a condom can require negotiation or persuasion skills that can be difficult to navigate, says Jennifer Evans, assistant professor and health education specialist at Northeastern University.

Historically, women have had no say in whether to engage in sex, and limited autonomy over their bodies, complicating sex-negotiation skills, Evans said.

Part of Evans’ research focuses on men who force women to have sex without condoms. A technique known as “stealing” is when a man puts on a condom but then removes it before or during sex without the other person’s knowledge or consent.

“In many of these thefts, the women are unaware that the condoms have been used incorrectly,” Evans said. “This means they may not engage in preventive behaviors such as taking Plan B or even having an early abortion.”

Evans found that heterosexual men who engage in theft often harbor hostile attitudes toward women. They report that sex without a condom feels better or say they “get the thrill of engaging in behavior that they know isn’t right,” she said. Evans cautions that women who suspect a sexual partner may not use a condom correctly to avoid having sex with that person.

“The consequences were already serious, but now they are,” Evans said Roe v. Wade Overturned, they are more so now.”

This story is a collaboration between KHN and Science Friday. Hear the conversation between KHN Senior Correspondent Sarah Varney and Science Friday Producer Shoshannah Buxbaum.

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