Plan B is an emergency contraceptive that is taken orally after having unprotected sex. It’s widely accessible and can be found in most stores with a pharmacy such as CVS, Rite Aid and Walmart. You do not need a prescription to purchase and will not be asked for your age at checkout, making Plan B super convenient for most people.
While it is not 100% foolproof, taking it within 24 hours of having sex is about 95% effective at preventing pregnancy. The tablet contains levonorgestrel, a synthetic hormone similar to progesterone, which acts to delay the release of an egg from the ovary, preventing subsequent fertilization with sperm.
However, a big concern with Plan B is that some studies show it to be less effective for those who weigh more than 165 lbs or have a BMI greater than 25. One study showed that it does not work at all for women over 175 lbs. This correlation has not been fully verified, and there are many conflicting studies at the moment. There also is not a consensus about why exactly the pill is less effective in heavier women. Because the FDA said that their studies were not definitive, they cannot include a warning label about weight limits.
This can lead some women who are above the effective weight range to buy Plan B as opposed to more effective forms of emergency contraception because they do not know about current research. With emergency contraception being so expensive (Plan B and comparable brands range $45-50 over-the-counter), it is important that there is a clear consensus available. We need more research around this issue to ensure women are able to make educated decisions about their health.
For now, there are alternatives to Plan B available for people with a higher BMI. One such alternative is Ella, which works in the same way as Plan B. In fact, it is more reliable than Plan B longer after unprotected sex. However, Ella requires a prescription to purchase, which can be difficult to get a hold of without prior planning. Additionally, it is around five dollars more expensive than Plan B. Some studies show that even Ella, however, is not as effective for those who weigh over 195 lbs.
Another form of emergency contraception is a Paragard IUD, also known as a copper IUD. IUDs, when inserted at most five days after unprotected sex, are 99% effective, making them the most effective form of emergency contraception. This process is more invasive, as the IUD needs to be inserted into the uterus. You would need to book a doctor’s appointment for the procedure, which can be logistically challenging. The procedure can also be painful for many women. For those who aren’t looking for a long-term solution, IUDs may not be the way to go because they last for 10 years.
While Plan B may not be as effective for women above a certain weight, doctors still recommend it if there are no alternatives available. If you have questions about which emergency contraceptive is right for you, the best thing to do is consult your OB/GYN, who can walk you through your options during your visit. Hopefully, more definitive research becomes available in the coming years so that we can save time and money without sacrificing our health in making these decisions.