As I was strolling around the streets of social media the other day, I happened to bump into a Facebook group for pregnant and nursing mothers.

Driven by curiosity to know the kind of issues they discuss, I hit the 'join' button. And the welcoming post I got was, "Nani ashawahi tumia P2 akajipata na ball?".

Hundreds of comments followed with ladies expressing their disgust, disappointments as well as regrets. Still, others were grateful that the emergency pill did fail and now they have their bundle of joy.

But why would you fall pregnant after using the emergency pill? You wonder. See, the EC does not guarantee 100% prevention from getting pregnant. Experts say it only reduces the chances by around 89%.

So, here are some instances under which you may still fall pregnant even after taking the pill:

1. Wrong timing

Most emergency pills are only effective when taken within a span of 72 hours after having unprotected sex. But as they say, the earlier the better. The longer you wait to use it, the less effective it is likely to be.

2. You throw up

People respond differently to these pills. Some will get nauseous while some can actually throw up. If you happen to throw up after swallowing the pill, you will need another dose to prevent pregnancy. Else, be ready to start the nine months journey to motherhood.

3. You are in your fertile window

Oops! Too bad for you if you had unprotected sex while in your fertile window. The fertile window includes four days prior to ovulation, the ovulation day and the day after ovulation. The EC works by delaying ovulation. So, if ovulation has already taken place, you are at a risk of getting pregnant.

ALSO READ: 5 myths about birth control pills you should stop believing

4. You have unprotected sex after taking the EC

Taking the emergency pill does not open doors for you to continue enjoying more unprotected sex. The pill is only intended to delay the ovulation and not stop it for good. So, once, you take the pill, you can either abstain or use other birth control methods such as condoms.

5. BMI

While being overweight does not necessarily mean that the EC will definitely fail, it affects its effectiveness. For people with a higher BMI, IUDs are better options.