In 2011, a team of researchers in Scotland were investigating why the emergency contraceptive pill, commonly known as Plan B, seemed to fail in a small portion of the population, and made an alarming discovery: the pill failed in higher rates in women with a higher BMI or body mass index.
Since then, several researchers have looked into why and how weight influences the effectiveness of Plan B, but have come up against several unknowns: it is unclear how much less effective the pill may be for people who are overweight or obese. and there is no clear research on how to help someone work around the problem.
Experts say it’s also difficult to zero in on a particular weight at which the effectiveness of Plan B drops. “Some studies say there is no effect above a BMI of 25, others say there are effects – different studies say slightly different things,” Dr. Siripanth Nippita, clinical associate professor of obstetrics and gynecology at NYU Langone Health. But in general, she says, as BMI increases, the effectiveness of emergency oral contraceptives decreases.
This glaring gap in the broader understanding of the emergency contraceptive can be explained in part by the fact that much of the research that led to its creation, in the mid to late 1990s, did not initially taking into account differences in body weight.
“When contraception was first developed, it was really a unique model,” said Dr. Alison Edelman, a professor of obstetrics and gynecology at Oregon Health and Science University, who has also studied the effectiveness of birth control contraceptives. ’emergency. “But our population now is very different from the population when the drugs were developed – we’ve grown in size – and we’re concerned that the most common type of emergency contraception won’t work for women with higher BMIs”
But, overall, the pill greatly reduces the chances of pregnancy. Here’s what we know.
Does plan B have a weight limit?
There are two forms of emergency contraceptive pills available in the United States: those that contain levonorgestrel, such as Plan B, and those that contain ulipristal acetate, commonly known by the brand name Ella.
The Food and Drug Administration authorizes these drugs for all women, regardless of weight. In 2016, the agency said it had completed a review of available research on levonorgestrel contraceptives and found the data to be “contradictory and too limited to draw a definitive conclusion” on whether the pills were effective. less effective in women weighing over 165 years. pounds or have a BMI over 25, which uses an individual’s height and weight to create a measure of overall health. Some doctors view BMI as a poor health assessment.
Studies, like the one from Scotland, seem to indicate that Plan B may be less effective in women who weigh more than 170 pounds, which is the average weight for American women over the age of 20, according to the Centers for Disease Control. and Prevention. “In some studies, we found decreased effectiveness in people over a BMI of 25,” said Dr. Nisha Verma, fellow of the American College of Obstetricians and Gynecologists. “But that doesn’t mean we don’t use it in these people.”
Ella doesn’t have as much of a decrease in effectiveness for people with higher BMIs, she added. But the pill may not work as well in overweight or obese people.
“The evidence is absolutely not clear and consistent,” said Dr. David K. Turok, professor of obstetrics and gynecology at the University of Utah.
Why would a higher BMI make plan B less effective?
Again, the science on this is unclear. Dr. Edelman said researchers look at four things when looking at a drug’s effectiveness: absorption, distribution, metabolism and excretion. A higher BMI may affect these four processes differently. In people with a higher BMI, drugs may be absorbed into the bloodstream at a slower rate, for example, or a drug may end up sitting in fat stores instead of “working for you,” a she declared.
Dr. Monica Woll Rosen, OB-GYN at the University of Michigan Medical School, pointed to other potential mechanisms, such as the presence of additional estrogen in peripheral tissues of overweight people, that may counteract the effects of a contraceptive, or that the dosage of Plan B and Ella may not be strong enough.
Can someone with a high BMI just take a higher dose?
Earlier this month, Dr. Edelman and his team published a study to determine if a double dose of Plan B would be effective for someone with a BMI over 30. They gave 70 people with a BMI over 30 a double dose or a single dose. dose of levonorgestrel and monitored them for a week. Unfortunately, the team found no statistically significant difference in suppressing ovulation – the primary function of Plan B – between the two groups, meaning a double dose might not be the easy way out.
In an emergency, however, a double dose of levonorgestrel should be enough to try. “It’s not dangerous to do that,” Dr. Edelman said.
What are the recommended options for emergency contraception if you have a higher BMI?
Doctors recommend Ella as a more effective emergency oral contraceptive than Plan B – for all women, but especially those with a higher BMI
You can take Ella up to five days after unprotected sex, although this requires a prescription. Some doctors recommend having it on hand, just in case you need to use it. “People should ask for it in advance and providers should offer it in advance,” Dr. Turok said.
An intrauterine device, if inserted within five days of unprotected intercourse, is an even more effective form of emergency contraception. The CDC considers the copper IUD, which does not contain hormones, to be an effective method of emergency contraception, but research shows that hormonal IUDs such as Liletta may also work. These devices act locally in the uterus, Dr. Rosen said, meaning “weight shouldn’t make a difference” to their effectiveness. The American College of Obstetricians and Gynecologists also recommends the copper IUD as an alternative to oral contraception for obese women.
However, not all women seeking emergency contraception will want a long-lasting method of contraception – IUDs can last anywhere from three to twelve years. And even for those who do, the process of getting an appointment within five days and booking time for the implant procedure can be difficult, if not impossible.
“We can spend all day talking about how effective a method is, but if someone doesn’t have access to it, it doesn’t work,” said Dr. Wing Kay Fok, gynecologist at Weill Cornell Medicine.
If you can’t take Ella or get an IUD implanted, doctors say plan B is worth it, regardless of your weight or BMI An analysis of four World Health Organization studies has shown that pregnancy rates among people who took plan B, in a variety of BMI categories remained below 3%, indicating that the drug will reduce your chances of getting pregnant, although it is not a guarantee of pregnancy prevention.
“Better sooner than later, and something is better than nothing,” Dr. Nippita said.