If you have a vagina and you take a morning-after pill as emergency contraception, you may be wondering how it could impact your use of regular birth-control methods. POPSUGAR spoke with two ob-gyns to explain why it depends on the type of morning-after pill and how you should proceed with continuing or starting hormonal birth control once using the morning-after pill.
Note: Depending on what morning-after pill you take, if you are over a certain BMI, there's a chance it may not be as effective [1], though the FDA says evidence for this is limited [2]. There are also possible side effects such as nausea, abdominal pain, and irregular bleeding [3].
Can You Take Plan B While on Birth Control?
Plan B is a progestin-only pill you should take within three days of unprotected sex (progestin is a synthetic form of progesterone [4]), and you can buy it over the counter. It interferes with ovulation so there's no fertilization and, therefore, no pregnancy. The Plan B website states, "Plan B does not impact the effectiveness of any regular birth control methods, so you can continue your regular birth control right away — or start one, if you don't have a regular method." The same goes for other progestin-only morning-after pills [5].
Board-certified ob-gyn and fertility physician Natalie Crawford, MD, told POPSUGAR this applies to going back on progestin-only birth control [6] as well as traditional combination birth control with both estrogen and progestin. She explained that when taking regular combination birth control as contraception, for example, the estrogen in those pills feeds back to the brain so you never send out any of the FSH hormone [7] that allows you to ovulate. "Taking a high dose of progestin with Plan B doesn't change that estrogen process of blocking the brain," she said.
Wendy Goodall McDonald, MD, who has worked in gynecology for 13 years, agreed. She, too, told POPSUGAR that taking either combination birth control or progestin-only birth control along with Plan B is fine. "You can take both [Plan B and birth control] at the same time because it really is just like additional ovulation blocking," she said. "It's not something that is working by a completely different mechanism."
If you're taking Plan B, chances are you missed some of your birth control [8] and had unprotected sex. Dr. McDonald noted that because you're taking Plan B, which itself is a form of emergency contraception, you can resume with birth control once every day [9] in the place you left off even if you skipped birth-control days. That being said, consulting your ob-gyn is always a good idea.
Again, that pulse of progestin from the Plan B is not going to change the effectiveness of your birth control, Dr. Crawford explained. "What freaks people out or confuses them is they feel like Plan B truly is a substitute for the birth-control pill, and they'll stop taking their pill pack, which is not what we want them to do."
Dr. Crawford said she'll see some patients become concerned that their birth control isn't working after using Plan B because the morning-after pill can interfere with your period [10]. She typically has to tell patients before they use Plan B that they should expect an abnormal period afterward due to the high dose of progestin, which could trigger menstruation.
Can You Take a Prescription Morning-After Pill on Birth Control?
The morning-after pill that you need a prescription to buy, ulipristal acetate (UPA), which is most commonly sold under the brand name Ella [12], should be taken up to five days after unprotected sex. Taking birth control at the same time could prevent this type of morning-after pill from working effectively, Dr. McDonald said, so it's suggested that you wait at least five days before you start back up [13] on your regular birth control (or begin birth control for the first time). As always, talk to your doctor for guidance.
A Note on Condoms After a Morning-After Pill
Dr. McDonald advises that you use backup contraception, like a condom, for at least a week after starting up on birth control again. "If you restart your pill in a timely manner [post morning-after pill], I usually tell people to be on their pill for at least seven days before they're unprotected because that's a good general window for preventing ovulation going forward," she explained. (Remember that you'd need to wait at least five days [14] to use hormonal birth control after taking UPA.)
"The effectiveness of either Plan B or UPA is really preventing pregnancy from an encounter that could have occurred three [with Plan B] to five days [with UPA] ago, but that's not necessarily preventing pregnancy for a future encounter," Dr. McDonald said. And Dr. Crawford wanted to remind you that birth control does not protect against STIs [15], so condoms are crucial in that sense.