Plan B pill (morning-after pill): how it works, when to take it and where to get it

The Plan B pill, also called the morning-after pill, is emergency contraception. It is a single tablet of levonorgestrel 1.5 mg, a hormone used in many birth control methods, and it lowers the chance of pregnancy after unprotected sex or a method failure (a broken condom, missed pills).

On June 20, 2013, the FDA approved Plan B One-Step for sale over the counter with no age limit. Its generic versions, with the same medicine and dose, are also over the counter with no age limit: look for "levonorgestrel 1.5 mg" on the box.

The Plan B pill is for emergencies. It doesn't replace a regular method: if you need one, see birth control online.

The sooner, the better. These are the options and their windows, according to the FDA and the CDC:

• Levonorgestrel (Plan B and generics): as soon as possible, within 72 hours (3 days). No prescription.
• Ulipristal (ella): as soon as possible, within 5 days (120 hours). Needs a prescription. According to the CDC, the two work about the same in the first 3 days, and ulipristal works better on days 3 to 5.
• Copper IUD: the most effective emergency option. It is placed in person within 5 days and can stay in as your regular method.

If more than 3 days have passed, don't give up: ulipristal or a copper IUD are still options.

According to the CDC, levonorgestrel may work less well than ulipristal in people with obesity. If this worries you, the doctor can evaluate you for ulipristal by video.

If your weight is higher or more than 3 days have passed, ask about ulipristal or a copper IUD. The doctor can help you decide.

Levonorgestrel 1.5 mg is sold over the counter at pharmacies in Puerto Rico. Some stores keep it on the family-planning shelf and others behind the counter: if you don't see it, ask the pharmacist. The price varies by pharmacy and between the brand and generics.

At night, check the pharmacy counters open 24 hours and call before you go. Ulipristal (ella) does need a prescription, so you need a visit with a doctor.

If more than 3 days have passed, if your weight may make levonorgestrel less effective, or if you have questions, request a birth control online visit with Dr. Diana Nieves Castro, MD, a general practice physician licensed in Puerto Rico. The doctor goes over when sex happened, your cycle and your medicines. If appropriate, the doctor prescribes and we send your prescription to your pharmacy.

Book an evaluation; the doctor decides whether a treatment is right for you. Doctor online 24/7: video doctor visits 24/7 — book online and choose your time right away. We send you a secure video link; it works on your phone, tablet or computer. You must be in Puerto Rico during the visit.

According to the FDA, levonorgestrel won't work if you are already pregnant and won't affect an existing pregnancy. It acts before a pregnancy starts. It is a different medicine from the one used to end a pregnancy.

According to MedlinePlus, the most common effects are changes in your period, spotting, nausea, vomiting, tiredness, headache, dizziness and breast tenderness. If you vomit within 2 hours of taking it, talk to a doctor: you may need another dose.

It's normal for your period to come up to a week earlier or later than expected. If it's more than 7 days late, take a pregnancy test. See when to take a pregnancy test. The CDC recommends a test if you haven't bled within 3 weeks after emergency contraception. If your cycle stays off, read about irregular periods.

The Plan B pill is sold over the counter with no age limit, so you don't need a visit to buy it. For a video visit, the age of majority in Puerto Rico is 21: if you're under 21, a parent or legal guardian signs the consent, stays on camera for the whole visit and shows photo ID. If that isn't possible, you can go to a CDT (community health center) or a family-planning clinic.

According to the CDC, after levonorgestrel you can start or continue your regular method right away, with condoms or another barrier for 7 days. After ulipristal, wait at least 5 days before starting a hormonal method (the pill, patch or ring), because it can make ulipristal less effective. Use condoms for those 5 days and for 7 more days after you start the method, or until your next period, whichever comes first.

To start a method, see the doctor through birth control online. The Plan B pill doesn't protect against sexually transmitted infections: if you had sex without a condom, consider STI testing and treatment. If you have a warning sign, see when to go to the ER.