Sexual Health:

Does the Morning After Pill Delay Period?

It is natural to want to know when and what to expect from your next period, as taking the morning after pill (emergency contraception) can have an impact on your menstrual cycle.

Most of the time, your period will come on time and be normal for you. Sometimes it can come earlier or later than expected, and it can be heavier or lighter than usual. Let’s discuss why this is the case.

What Is The Morning After Pill?

The morning after pill is a type of emergency contraception. It is taken by women who have had unprotected sex (without reliable contraception) or whose contraceptive method has failed, to reduce the chances of pregnancy occurring.

This pill does not protect you from sexually transmitted infections (STIs). If you had unprotected sex, we recommend you go to your local STI clinic, alternatively, you can order an STI Home Test Kit.

There are two types of morning after pill available in Ireland.

  1. Levonorgestrel (Plan B One-Step)
  2. Ulipristal acetate (EllaOne)

Levonorgestrel is available without a prescription, while ulipristal acetate is only available with a prescription.

The morning after pill is recommended as a backup method of contraception, not as the regular method. If you require regular reliable contraception, you can request a prescription for the contraceptive pill, patch or ring.

Does The Morning After Pill Delay My Period?

Most of the time, the morning after pill does not affect your period. However, sometimes it can cause your period to be heavier or lighter than normal and it can cause it to start earlier or later than usual. 

It can also cause irregular bleeding or spotting after you take it that may persist until your next period.

You should take a pregnancy test and speak with a doctor if:

  • Your period is delayed by more than 7 days
  • Your period is heavier or lighter than usual 
  • You have bleeding/ spotting that heavy or does not stop after your next period

Other things can influence when your period arrives. Your period may also be delayed if:

  • You have irregular cycles
  • You are stressed
  • Other medication you are on interfere with your cycle
  • You have recently lost weight 
  • You have certain health issues such as thyroid disorders, diabetes, or polycystic ovary syndrome (PCOS)

If your period is a little bit late, you may not be pregnant, but it is important to check this.

You should be aware that a pregnancy test cannot be relied upon to exclude pregnancy until 21 days after you’ve had sex. You may want to take a pregnancy test after 21 days to ensure the emergency contraception has worked. 

If you are concerned that you might be pregnant, you should speak to a GP.

The morning after pill should not be used to try and delay your period. This is not a reliable way to delay your period and is not the intended use for this type of emergency contraception. We recommend that you request a prescription for period delay pills should you wish to delay your period.

How Can The Morning After Pill Delay My Period?

The morning after pill can interfere with your period as it prevents ovulation. Ovulation takes place when your ovaries release an egg in preparation for fertilisation. Ovulation usually occurs in the middle of your menstrual cycle and plays an important role in determining when your period starts and regulating your cycle. If this is disrupted then the expected date of your period can be affected. Your next cycle can also be affected – it may be longer or shorter than usual.

How Late Can You Take The Morning After Pill For It To Be Effective?

This depends on which pill you are taking. 

Levonelle is licensed up to 72 hours after unprotected sexual intercourse (UPSI), but in some situations, it can be prescribed by a doctor up to 96 hours after UPSI. 

EllaOne is licensed up to 120 hours after UPSI.

The sooner after UPSI these pills are taken, the more effective they will be. 

The morning after pill will only work if you take it before ovulation has occurred.


How Late Can Your Period Be After Taking The Morning After Pill?

If your period is delayed after taking the morning after pill, most of the time it will start within a week of the expected date, however, very occasionally it can be delayed for several weeks. 

If your period is more than a week late, or it is lighter than usual, you should arrange a pregnancy test, and speak to a GP.

How Do I Know Whether The Morning After Pill Has Worked?

The only way to reliably tell if emergency contraception works is to wait 21 days after your next period and do a pregnancy test. In most cases, if your period arrives within a week of its expected date and is ‘normal’ for you, it is extremely unlikely that pregnancy has occurred. Unfortunately, this means there are no immediate answers.

How Effective Is The Morning After Pill?

Both morning after pills (Plan B One-Step and EllaOne) are effective, but they are not as reliable as regular contraceptive methods and should only be used in emergencies. They are most effective if taken within 24 hours of UPSI, and this decreases the longer the time from UPSI. 

Effectiveness can also be influenced by other medications, or if you have already used emergency contraception during that cycle. 

Find more information on emergency contraception.

What Is The Most Effective Form Of Emergency Contraception?

The Copper Coil, also known as the Post-Coital IUD is 99.9% effective. It is the most effective form of emergency contraception and is usually inserted up to 5 days after UPSI. It can still be used after taking one of the emergency contraceptive medications.

The Copper Coil has an inhibitory effect on both fertilisation and implantation. Unlike the emergency contraceptive pills, the copper coil can be effective even after ovulation has occurred. It has the added benefit of providing ongoing regular contraception and can be left in place for up to 10 years. If regular contraception is not required, or another method is preferred, it can be removed after your next period.


Repeat Prescription

Period Delay Treatment

Order a prescription for Period Delay Treatment online with! Once your request has been approved, we can send your prescription directly to your chosen pharmacy via secure Healthmail.

Where Can I Get A Prescription For Period Delay Tablets?

You can request a prescription for Period Delay Medication via our online prescription service. All you need to do is fill in a short and secure questionnaire. You can do this on your mobile, laptop or tablet, 24 hours a day, 7 days a week.

Then, one of our GPs will review your request to make sure the treatment is clinically safe and suitable for you. Once your request has been approved, we will send your prescription directly to an Irish pharmacy of your choice. There is no GP appointment required!

How It Works

Through an online medical questionnaire, face-to-face video consultation or home health test, our online doctors will review your case and prescribe the best treatment for you.

Step 1

Online Questionnaire

Fill in a secure and simple online questionnaire for your desired service.

Step 2

Medical Review

Our Irish-registered doctors will review to ensure you are medically suitable.

Step 3

Decision Made
Your treatment will be approved if you are deemed medically suitable.