Science of Sex: BMI And Birth Control Efficacy

March 30th, 2019

bmi and birth control efficacy

This month’s very late Science of Sex post was motivated by the new Hulu show Shrill, which reminded the world that emergency contraception may not be as effective for overweight people. Specifically, the brand Plan B (also known as the morning after pill) EC is rated up to 175 pounds, which is just over the average weight of an American woman.

The results of a large European study show that the popular form of EC, levonorgestrel 1.5 mg, (Plan B pill) loses its potency in women weighing about 165 pounds and does not work at all in women weighing 175 pounds or more.

There are several theories as to why.

  1. Having more fat makes pills break down more quickly. This makes the medication less effective.
  2. Overweight people have more blood, so more birth control is required to reach ideal blood concentration levels.

Researchers haven’t pinpointed which theory, if either, is correct. All we know is that EC might not be reliable for many people. This was something I learned last year thanks to Reddit, but it’s not something that many people have heard from doctors, pharmacists, or other professionals. Even the manufacturer denies this to be the case.

Fortunately, there is another option: Ella. According to the study, Ella is more effective than Plan B for overweight users, and you can take the pill up to five days later. In comparison, Plan B loses effectiveness after 72 hours. However, you may need a prescription for Ella.

Ella bested Plan B by half, with about 50% fewer pregnancies than those taking levonorgestrel.

Additionally, you may be able to double up on doses of Plan B to increase its effectiveness if you are overweight.

This increased risk of pregnancy doesn’t end with EC. Cochrane examined different studies and found mixed results. The effectiveness of birth control didn’t decrease universally as BMI increased, but the patch and some birth control pills were less effective for overweight and obese users. Shots, implants, and hormonal IUDs were not less effective.

Across the board, IUDs are touted as being the most effective birth control or EC regardless of BMI.

But any contraception is better than none. The European Medicines Association advises that using Plan B is better for overweight people than using no EC. You just need to be aware of the risks.

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Categories: Science of Sex

Where Has All the Plan B Gone?

October 20th, 2011

I’d never heard of Jane Pratt or any of her work before the recent uprising over the article GET IT TOGETHER, GIRLS: Every Goddamn Pharmacy in New York is Out of Plan B! Every ONE!. I’m just young enough and located in an isolated enough location that (maga)zine culture never really flourished in my life. Sassy? Too alternative to be sold in my hometown and if it wasn’t Gothic Beauty or Revolver, I probably didn’t care.

So this article started popping in on my radar a few days ago and I was like “What is this website?” and furthermore “What are they talking about?” You see, the article itself is written so poorly that it’s really difficult to copy and paste it into your own post — to add commentary — in a way that makes sense. I didn’t actually read the article until avflox’s analysis on BlogHer appeared on my radar.

And all I can say now is “What the fuck?!”

Some people have posited that this article, which praises the virtues of Plan B over other birth control while admonishing women for buying so much Plan B that the entire city of New York has run out, is perhaps performance art. How can a young woman be so ignore, sheltered or naive? I guess they never read Overheard in New York which proves that the entire city is pretty much one french fry short of a happy meal. Not to worry rest of the world, ’cause the entire Internet proves you’re a bunch of morons.

But, really, even this is going too far. The writer in me is offended by the overuse of capitalization and the under-use of any sort of grammar but my humanity is offended at every other fucking part of this post. Who needs a God damned list of why birth control is too inconvenient to use? Who needs this convoluted B.S. that is full is misunderstanding — and shaming! — about our bodies! Cat literally describes the way that Plan B works as “THIS IS TOO, TOO TERRIFYING AND I REFUSE TO UNDERSTAND IT.” And how more classist can you get than by insisting that $50 is something every woman should be able to shell out multiple times per month for a non-prescription form of birth control? And, hey, if you are that woman who is shelling out all that money — it’s practically a new fall fragrance, you guys!!!!! — how’s your body doing with the super-dosage of hormones? I can’t imagine that feels good.

Perhaps the only thing worth reading in this article is Cat’s admission that there is clearly abuse of Plan B and if other women aren’t abusing it, then at least she is. Yes, Cat, maybe you are abusing Plan B because or poor planning skills or because, apparently, you’re a fucking moron. Darwin and I would both agree that you should keep using Plan B so that your genetic line ends with you.

Flaming aside, I cannot help but wonder what other factors are at work. Are pharmacies not providing (much) Plan B because of their “moral” compasses? Was there a bad bad or something else that temporarily slowed or halted production? Is October just a really busy fucking month? See what I did there?

We all saw what Cat did there. She made a fool of herself. She shared some seriously incorrect information to impressionable minds on the Internet and the folks over at xoJane? Didn’t do a God damned thing about it. If any of them have a Plan B for saving their reputation, now’s the time to enact it.

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Categories: Everything Else, internet

Image © MisterUnlucky; used with permission.