June 8, 2023

You Took Postinor-2 And Your Period Is Late - Meaning & What to Do 

Article fact-checked and approved by Dr. Didi Emokpare
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Postinor 2 (or the morning-after pill) can cause a delayed period, but other factors can also contribute to it. While the pill effectively prevents pregnancy, there is still a slight chance of pregnancy. Take a pregnancy test if your period is significantly delayed and consult a healthcare professional for personalised advice. 

It can be a scary experience when there’s a change in your menstrual cycle, especially when you're sexually active and have taken Postinor-2.  

Like many other emergency contraceptive pills, Postinor-2 has some expected side effects which include delayed periods. But how late does it become a concern? If your period is late after taking Postinor-2, what do you do?  

 I have prepared this article to walk you through everything you need.  

Late Period After Taking Postinor-2 - What You Should Know 

If you have taken Postinor 2 and your period is late, a few factors could be behind the situation. It’s not always an indication that you’re pregnant.   

1. Delayed period 

Postinor 2 can sometimes cause changes in your menstrual cycle, including a delay in the start of your period. This is a known side effect of emergency contraception. Postinor-2 contains an extra-strong dose of levonorgestrel (a type of synthetic progesterone, aka progestin), which can do a number on your menstrual cycle, including delaying your period.  

Interestingly, researchers in this 2007 study found that about 15 per cent of women who took Plan B experienced significant changes in menstrual cycle length, period length, and menstrual appearance. 

So when you experience a late menstrual cycle, there’s a possibility that the pill is taking effect, and it’s nothing you should be worried about. 

However, this side effect can vary from person to person. Some women may have their period a week earlier, while others may have it a week later. Everyone is different.  

But after about two weeks and you’ve not seen your period, the chance you’re pregnant increases. 

2. Timing of your period 


Various factors, including stress, hormonal changes, diet, and other medications, can influence your menstrual cycle. Therefore, your late period may not necessarily be due to the morning-after pill alone. 

Meanwhile, the average timing delay is within a week when you take an emergency contraceptive pill. But it’s likely to affect your menstrual cycle. This 2006 study suggests that the earlier in your process you take Plan B, the earlier your next period will be.  

While this may not be true for all women who take EC, it’s worth considering.  

3. Effectiveness of the Postinor 2 

Postinor 2 prevents pregnancy if taken within 72 hours (three days) after unprotected sex. However, its effectiveness decreases over time, so it is most effective when taken as soon as possible. If you took the pill very late after having sex and now your period is late, pregnancy’s possible, leading us to the next point.  

4, Possibility of pregnancy 


While the morning-after pill significantly reduces the risk of pregnancy, it is not 100 per cent effective. It has a pregnancy risk reduction rate of 95 per cent if taken within 24 hours or 88 per cent between 24 and 72 hours. So, there is still a tiny chance of becoming pregnant even after taking Postinor 2 correctly.  

Late Period After Taking Postinor-2 - What To Do 

1. Understand the situation 

It’s normal to be worried when your period is late after using EC pills. It makes you want to conclude that the pill was ineffective. But you may be surprised to eventually realise that the fear of getting pregnant and the hormonal changes related to stress are causing your period to be late.  

If you don’t have any symptoms that might indicate pregnancy (such as nausea, swollen breasts, etc.), you can wait a week before the expected date of your period before doing a pregnancy test. 

This way, you’ll be sure of the situation and the accuracy of the results.  

2. Take a pregnancy test 

If your period is significantly delayed (more than a week) after taking Postinor-2 or you are experiencing unusual symptoms, it is recommended to take a pregnancy test. 

Home pregnancy tests such as the urine test are readily available over the counter and can provide accurate results. 

3. Consult a healthcare professional  

If the test comes back negative and you still don’t have your period, I recommend you make an appointment with your doctor so they can examine you. In case of any doubt, the doctor or gynaecologist will prescribe a blood test to check your beta-hCG (the hormone secreted by the placenta) and determine what’s going on with your body. The healthcare professional will provide personalised advice based on your specific situation.  

Can p2 make you miss periods for a month? 

Yes, you may experience a delay in your period for the next month's menstruation cycle or even bleeding outside the typical menstrual cycle after taking Postinor-2 because it contains synthetic hormones. An abnormal lapse in monthly menstruation is called amenorrhea. Some women who take emergency contraception may have lighter bleeding, and others may skip their periods entirely. Remember, the information provided here is not a substitute for professional medical advice. It's always advisable to seek guidance from a healthcare professional for personalised and accurate information regarding your circumstances. 


Is late menstruation a side effect of Postinor-2? 

Yes. Postinor-2 can cause changes in menstrual bleeding patterns. It's not uncommon for the menstrual cycle to be affected, leading to a delayed or early period. Other factors can also cause late menstruation, so consulting a healthcare professional is recommended. 

Why does p2 delay periods? 


Postinor-2 contains levonorgestrel, a synthetic hormone that can affect the menstrual cycle. The hormonal changes caused by the pill can disrupt the normal menstrual cycle. However, individual responses may vary. Postinor-2 contains levonorgestrel, a synthetic hormone that can affect the menstrual cycle. 

How long does postinor delay pregnancy?  

Postinor-2 is most effective when taken as soon as possible after unprotected intercourse. It can reduce the risk of pregnancy by up to 95% if taken within 24 hours. However, its effectiveness decreases with time, so it's recommended to take it within 72 hours (3 days) after unprotected sex. 





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