Whether you suffered from a condom mishap or a total lapse in judgment, having a backup plan is key when it comes to preventing unwanted pregnancy.

It is safe and effective and it is available over the counter from any pharmacy, without a prescription. You don’t have to give an explanation, you just ask for it. Knowing a few key facts about your options before you need them will save you a ton of stress later on. Here, the most important things to know about the morning-after pill:

READ MORE: 12 Contraceptives You Should Think About Trying — Other Than The Pill

1/ It should be taken 12 to 72 hours after you had unprotected sex, but the sooner the better.

While 72 hours may sound like a long time that doesn’t mean you should put off your trip to the pharmacy.

2/ The newer products can be taken after five days, but make sure you follow the instructions. 

Ella is a newer form of emergency contraception that can be taken up to five days after your oops moment, though it’s only available with a prescription. It also works by stopping or delaying ovulation, but it carries the same effectiveness for five days, rather than just 72 hours.

3/ It prevents ovulation and does not cause an abortion and it can’t halt a pregnancy.

Research shows that the main mechanism of action is inhibiting or delaying ovulation – so the egg wouldn’t even be released. Some research has looked at the possibility that emergency contraception might also affect the lining of the uterus in a way that would make implantation harder (on the off chance that an egg was already released and fertilised, but not implanted, when you took the pill) but other studies have not found evidence for this.

So what if the egg was already released, fertilised, and implanted before you got a chance to take the pill? Well, in that case, you’re pregnant. Hence why it’s important to take the pill sooner rather than later (despite the 72 hour window).

4/ It does not protect you for the rest of your cycle — you could fall pregnant later in that cycle again.

There are no safety concerns with using it every week; however, it’s not as effective as any ongoing method of contraception like the Pill. While emergency contraception is still highly effective it is still not as reliable or effective as routine birth control (not to mention it’s way more expensive than other options).

5/ It could delay your period for up to a week — so don’t freak out!

Don’t be shocked if your flow is a little off during the month that you take EC (emergency contraception). Your period may be earlier, later or heavier than normal as a result of the medication, though it can also change due to stress (and who wouldn’t be anxious after a birth control failure!). However, if your cycle is more than a few days late, you may want to take a pregnancy test. 

6/ It will not protect you against STIs.

Fact!