Skip to main content
Skip to main content

Media Relations

Morning-after pill may not work for overweight women

(CNN) -- An emergency contraceptive manufactured in Europe will come with a new label in 2014, warning that the pill may not be effective for women over a certain weight.

The same may be true for emergency contraceptives in the United States.

French manufacturer HRA Pharma was conducting research on another topic related to its emergency contraceptive Norlevo when scientists realized there was "a clear impact of weight" on the drug's effectiveness, CEO Erin Gainer said.

HRA Pharma scientists discovered Norlevo began losing its effectiveness when women reach about 75 kilograms, or 165 pounds, Gainer said, and showed an "absence of effectiveness" at about 80 kilograms, or about 176 pounds.

"We felt it was our ethical duty ... to report those results to our health authorities here in Europe," Gainer said.

Norlevo is identical to the emergency contraceptive Plan B One-Step, said Kelly Cleland, a public health expert at Princeton University. Both are LNG ECs, or emergency contraceptives that include levonorgestrel, a synthetic version of the hormone progestogen. Emergency contraceptives are often called the morning-after pill because they work by interfering with ovulation, preventing the fertilization of an egg.

Teva Pharmaceuticals, which manufactures Plan B, did not respond to CNN's request for comment.

The Food and Drug Administration "is currently reviewing the available and related scientific information on this issue, including the publication upon which the Norlevo labeling change was based," said spokeswoman Erica Jefferson. "The agency will then determine what, if any, labeling changes to emergency contraceptives are warranted."

Plan B is available in the United States without a prescription to anyone of any age. Its generic versions Next Choice One Dose and My Way are also the same as Norlevo, Cleland said.

Under U.S. federal law, generic brands cannot change their labeling until the name brand product does. "Actavis' Next Choice One Dose is approved by the FDA as a safe, effective and therapeutically equivalent treatment option to its brand counterpart," said Actavis spokesman David Belian. "Therefore, should any update to the Plan B labeling take place, we would make the appropriate change to our product as well."

European health authorities approved the Norlevo label change a few weeks ago, but it will take several months to implement in all the countries HRA Pharma supplies, Gainer said. The new packaging slip will say the emergency contraceptive is "not recommended ... if you weigh (165 pounds) or more," according to Mother Jones, which first reported the story.

It is unclear why emergency contraceptives may be less effective for overweight women, said Anna Glasier, an expert in reproductive medicine at the University of Edinburgh. Glasier published a study in 2011 that analyzed the risk of pregnancy for women who had taken emergency contraception.

Glasier and her colleagues found that obese women had three times the risk of getting pregnant after taking emergency contraception than those with a normal body weight. The risk was greater for those who had taken levonorgestrel pills, compared with those who had taken ulipristal acetate, which is used in another emergency contraceptive called Ella.

"There has been some evidence over the years that low doses of progestogen-only contraceptives have less efficacy in heavier women, but we do not know why," Glasier told CNN. That said, "it is well recognized that body weight affects the way drugs are metabolized."

Previous research has shown that women who weigh more than 155 pounds are at a higher risk of regular oral contraception failure. These drugs take longer to reach normal concentration levels in the blood of obese women compared with normal weight women,according to one study. That may be one reason emergency contraceptives are less effective.

Glasier noted that the number of obese women in her study was small, so it's hard to make broad recommendations based on the research. In the general population, studies show levonorgestrel emergency contraception prevents about 50% of expected pregnancies.

"You are probably better to take LNG-EC after unprotected sex than just to leave it to chance even if you are obese," Glasier said.

"When faced with a choice ... I don't think the findings are strong enough for us to tell women that they should not use LNG-EC," Cleland agreed. "Because Plan-B One Step is now available over-the-counter and is by far the easiest EC method to get, this is the method that most women are familiar with."

Cleland recommends overweight women who are worried about the pill's effectiveness use an emergency contraceptive with ulipristal acetate, or a copper IUD. IUDs, or intrauterine devices, can be inserted by a doctor up to five days after unprotected sex to help prevent pregnancy.

It's important to note that women shouldn't be relying solely on emergency contraception to prevent pregnancy. "The best way to reduce the risk of unintended pregnancy among women who are sexually active is to use effective birth control correctly and consistently," the Centers for Disease Control and Prevention says. Find the method that works best for you by talking to your doctor.

CNN's Miriam Falco contributed to this report.




All News  Now Viewing Category: All
Glasgow News
School of Journalism & Broadcasting
WKU Regional Campuses
Kinesiology, Recreation & Sport
Housing & Residence Life
Media Relations
Academic Affairs
Augenstein Alumni Center
Instruments of American Excellence
Emergency Preparedness
Department of Music
Department of Theatre & Dance
Library News
Office of Sustainability
Office of International Programs
Office of Research
Ogden News
WKU Parent and Family Weekend
Parent's Association
Student Activities and Organizations
Scholarships Student Financial Assistance
Student Government Association News
Van Meter Auditorium
Teaching News
Study Abroad
Student Research Council
Student Employment
WKU Joint Admissions
International Student Office
Human Resources News
Cultural Enhancement Series
The Confucius Institute
Campus Activities Board
The Gatton Academy of Mathematics and Science in Kentucky
Development and Alumni Relations
Downing Student Union
Health Services
Hardin Planetarium
News from The Center for Gifted Studies
Student Financial Assistance
Downing Museum
Etown & Fort Knox
Employee Wellness
Latest Headlines
WKU wins Hearst Intercollegiate Photojournalism Competition for 23rd time

WKU’s School of Journalism and Broadcasting has won the Hearst Journalism Award Program’s Intercollegiate Photojournalism Competition for the 23rd time in the past 28 years.

Gabbi Doolin Memorial Scholarship Fund Established

The memory of Gabbi Doolin will live on forever through the establishment of the Gabbi Doolin Memorial Scholarship Fund, administered through the College Heights Foundation at WKU.

Parking and Traffic Changes

March 24th - 26th

Featured Articles
Vic Richey to Discuss Leadership in Upcoming Lecture
WKU Learn and Earn Program

The Learn and Earn program at WKU partners with area companies and businesses to employ both traditional and non-traditional college students thus helping meet their company production goals. For more information, visit

Construction webcams available to view construction

Construction webcams are now in place so you can watch the progress of Hilltopper Hall and the Southwest and Northeast Hall connectors online: - images are uploaded from 5 am-5 pm.

Note: documents in Portable Document Format (PDF) require Adobe Acrobat Reader 5.0 or higher to view,
download Adobe Acrobat Reader.

Note: documents in Excel format (XLS) require Microsoft Viewer,
download excel.

Note: documents in Word format (DOC) require Microsoft Viewer,
download word.

Note: documents in Powerpoint format (PPT) require Microsoft Viewer,
download powerpoint.

Note: documents in Quicktime Movie format [MOV] require Apple Quicktime,
download quicktime.

 Last Modified 9/24/14