Health & Wellness

What Does The Morning After Pill Do?

Learn more about the morning after pill and emergency contraception 💊 Article Written By Leslie, Nurse Practitioner
by Nurse Leslie
29 Sep 2022

UPDATED: 12 Jan 2023


Image Source: Photo by Reproductive Health Supplies Coalition on Unsplash

The “morning after pill” (also known as Plan B, the second day pill or emergency contraception) is a medication that is taken after having sex to prevent pregnancy. The phrase, however, is a bit of a misnomer – these medications can be taken multiple days after having sex, and in fact, not all emergency contraceptives come in pill form. Read on to discover how these medications work, when to take them, and what to expect afterward. 

💊 This article has been written by a working medical professional.

We firmly recognize there are many different ways to have sex, but for the sake of brevity, we will refer to unprotected penis-in-vagina sex as “sex” from here on out. Unprotected sex could mean many things, but generally refers to not using any type of contraceptive or birth control, or failed contraceptives or birth control such as a broken condom, forgotten/missed contraceptive pills, etc.

How does emergency contraception differ from birth control and abortions?

You’ve likely heard that the morning after pill, abortions, and birth control are different ways of avoiding pregnancy, but some people get them mixed up. Let’s review how the three are distinct. 

Emergency contraception (EC) is used after having sex in order to prevent pregnancy. 

Traditional birth control (such as using a condom and contraceptive pills) is used before or during sex to avoid pregnancy. 

An abortion is done after someone is already pregnant to terminate the pregnancy.

What does the morning after pill do

In order to understand how EC works, it can be helpful to review how pregnancy occurs within the human body after penis-in-vagina penetrative sex. This will be a simplification; the steps and timeframes may be different due to normal human variation, or if pregnancy is being achieved through assisted reproductive technologies such as intrauterine insemination (IUI) or in vitro fertilisation (IVF).

Every menstrual cycle, an egg matures and is released by the ovary – this is called ovulation and it happens every 3-5 weeks on average. Once ovulated, the egg must be fertilised by a sperm within approximately one day, or else it begins to degrade. After being ejaculated, sperm can live up to about 5 days in the partner’s genital tract before dying. Did you know there’s therefore only about 6 days during a menstrual cycle that a person could actually get pregnant? The fertilised egg must then travel to the uterus and nestle into the uterine lining – this is called implantation. Medically speaking, a person is usually considered pregnant when implantation has occurred. Now let’s review how EC interferes with this process and prevents pregnancy.

Emergency contraception – pill form

There are a few major types of morning after pills. The traditional type is Plan B (also called levonelle) and it contains a synthetic form of progesterone hormone called levonorgestrel. The large dose of progesterone hormone primarily works by delaying or preventing ovulation. A newer, more effective medication is called ella or ellaOne. The drug it contains is ulipristal acetate, and it works by affecting how the body reacts to progesterone, therefore preventing ovulation for 5 days. A third option is utilised when these previous two medications are unavailable. With a healthcare provider’s prescription, traditional birth control pills (which contain both progesterone and oestrogen hormones) can be used as EC when taken in a specific, high dose. 

Emergency contraception – copper IUD

There is another EC method that does not involve taking a pill orally, and that is the Copper intrauterine device (IUD). The Copper IUD is a T-shaped birth control device containing – you guessed it – copper! It’s inserted into the uterus (the hollow reproductive organ that houses a pregnancy) by a trained clinician. Even though it was developed for use as birth control, it can also be used as EC primarily because the copper ions affect the sperm’s ability to move and find the egg. A benefit of this method is that the IUD can then be used as birth control for 5-10 years thereafter, depending on the brand. It’s a two-for-one deal! There are other types of IUDs that contain progesterone hormones; these are currently being researched to see if they would be appropriate for use as EC. 

There are additional benefits, risks, and side effects of the copper IUD, and not all clinicians provide this as an EC method, so please discuss with them to see if it’s an option for you. 

When to take morning after pill 

This is very important, so listen up: all EC methods are more effective the sooner you use them. Plan B can generally be taken up to three days after sex. You can get it over the counter at a pharmacy without a prescription. Ella can be taken up to five days after sex. In the US, a prescription is required for Ella. In the UK, a prescription may be required depending on your age, but if eligible, you can order ellaOne directly from their website. The copper IUD is generally inserted within 5 days of sex, however this time frame could be shorter or longer based on the clinician’s judgement. Ella and the copper IUD are more effective than Plan B if you weigh over 165 lbs, however you can still safely take Plan B if it’s the only option available. It’s best to get individualised advice from your pharmacist or clinician if possible.

Since EC options may vary based on what country you reside in, different sources may be helpful to different individuals. The NHS has lots of helpful information on how to obtain EC if you live in the UK. For those who live in the US, Planned Parenthood is super useful both in person and online for educational purposes. Finally, the World Health Organization is also a fantastic worldwide resource. 

Morning After Pill Side Effects

Generally speaking, the side effects of morning after pill are well-tolerated. Nausea, headache, and irregular bleeding and spotting are the most common. Some people say these symptoms are more intense after taking the combined oestrogen/progesterone type of morning after pill. After getting a copper IUD, you may experience heavier and more crampy periods. That being said – don’t hesitate to call your doctor and run any concerns by them, as sometimes pain and bleeding are indications that something has gone wrong with the IUD, or that you may in fact be pregnant.

Morning after pill side effects menstrual cycle

A commonly asked question is: can the morning after pill delay your period? And the short answer is yes, it could delay your period. While there is no set maximum delay in periods after taking the morning after pill, it is generally recommended that you take an at-home pregnancy test if your period is a week late or more. If you have any other concerning symptoms (pain, irregular bleeding, severe nausea and vomiting, late period with or without a positive pregnancy test) then call your healthcare provider straight away.

Pregnant after Morning After Pill Symptoms

While EC decreases your chance of becoming pregnant, it is not 100% effective at preventing pregnancy. Pregnancy symptoms can actually be quite similar to side effects of the morning after pill – spotting, nausea, and headaches to name a few. However the hallmark symptom of pregnancy is missing your period (this includes having bleeding or spotting that is not like your normal period). If your period is not returning to normal, or you’re having pregnancy symptoms after the morning after pill, it never hurts to take a pregnancy test and book an appointment with your GP or gynaecologist regardless of the result. Having taken the morning after pill is not shown to have any harmful effect on a pregnancy either, FYI.

Even if you do get your period after taking EC, there are benefits to following up at your GP or gynaecology office. EC doesn’t protect you against sexually transmitted infections (STIs), and it is also not useful for contraception in the future. By booking an appointment, you can get STI testing and if desired, discuss more effective contraceptive options moving forward. 

If you are not comfortable going into the office, at-home self testing for certain STIs is available in some countries and cities. And you don’t need to leave your house to get condoms, either. If you live in the UK, HANX offers both discreet morning after pill and condom delivery. 

Read our refresher on how to use condoms without being awkward, become a safe sex hero, and reduce the need for EC again in the future!