So, you took Plan B, aka the morning-after pill, after a condom mishap. Now you’re anxiously waiting and wondering: “Did it work?” “What if I’m pregnant?” “How would I even know?” The morning-after pill is designed to prevent pregnancy, not end it, and when taken within 72 hours, it’s pretty effective. But it’s not foolproof. Here, we’ll walk you through the signs that Plan B might not have worked, what to watch out for, and what you can do if you suspect things didn’t go as planned.

First, what is Plan B, and how does it work?

Plan B (levonorgestrel) is an emergency contraceptive that delays ovulation; in simpler terms, it prevents your egg from being released so sperm won’t have anything to fertilise. It’s most effective when taken within 24–72 hours after unprotected sex, but the sooner you take it, the better. According to the World Health Organisation (WHO), Plan B can reduce the risk of pregnancy by 89% if taken within 72 hours. It’s worth mentioning that if you’ve already ovulated, Plan B might not stop pregnancy. And if your body doesn’t respond to it properly, maybe because of timing, body weight, or medication interactions, it might not do its job at all.

So, what are the signs that your emergency contraceptive didn’t work?

Let’s get into it. Here are some real signs your Plan B might not have been effective:

1. Your period is over a week late

This is the biggest red flag. If your period is more than seven days late after taking Plan B, it's time to take a pregnancy test. Normally, your period might come earlier or later than usual due to the hormones in the pill, but it should arrive within a week of your expected date. If it doesn’t, don’t guess, pee on that stick.

2. Your period is extremely light or spotty

While Plan B can mess with your cycle, a very light or spotty period, especially if it’s way shorter than normal, could be a sign of implantation bleeding. This can happen about 6–12 days after conception. If you're spotting and it doesn't feel like your usual period, take note.

3. You’re feeling pregnant (yes, that’s a thing)

Tender breasts, fatigue, nausea (especially in the morning), and even food aversions are all early signs of pregnancy. If these symptoms show up a couple of weeks after you took Plan B, your body might be trying to tell you something.

4. You took Plan B too lateImage unavailable — 5 warning signs your emergency contraceptive didn't work Original source

Timing is everything. If you took it more than 72 hours after unprotected sex, its effectiveness drops significantly. By 5 days (120 hours), it may not work at all. If you suspect you’re outside the safe window, Plan B might not be your backup anymore; it’s just a placebo at that point.

5. You threw up shortly after taking it

If you vomited within 2 hours of taking Plan B, there’s a high chance your body didn’t absorb the medication. This means you didn’t actually get the protection you were counting on. In this case, doctors recommend taking another dose immediately.

What to do if you suspect Plan B didn’t workImage unavailable — 5 warning signs your emergency contraceptive didn't work Original source

So now you’ve got a late period, or you’re dealing with weird symptoms and stressing. What next?
  1. Take a pregnancy test: Wait at least 2–3 weeks after the incident or 1 week after your missed period. Home pregnancy tests are widely available in Nigeria, and they’re pretty accurate.
  2. Go to the hospital: If the test is positive, schedule an appointment quickly. If it’s negative but your cycle is still acting strange, it’s still worth checking in with a doctor.
  3. Consider long-term options: If emergency contraception feels like a regular event in your life, it might be time to talk about more reliable, long-term birth control. There are plenty of options in Nigeria today, from pills to injectables to implants.
If you think your Plan B didn’t work, don’t panic. Get the facts, take action, and don’t hesitate to see a doctor.