Gestation Calculator

This calculator has been designed to give you an idea of the treatment options available to you*. If you decide to have an abortion with Marie Stopes UK, one of our nurses will give a more approximate gestation date during your appointment by way of a scan.
*Please note that this online calculator will only give you an estimated gestation based on the details you have provided.

Please select the first day of your last menstrual period.



We are here to support you 24 hours a day, 7 days a week

Call us now on 0345 300 8090 or email services@mariestopes.org.uk

0345 300 8090

You are here

Which emergency contraception is best for me?

If you've had unprotected sex or think your contraception hasn't worked properly, you could be pregnant. There are two kinds of emergency contraception available to reduce the risk of an unplanned pregnancy - the emergency contraceptive pill (sometimes known as the 'morning after pill') and the IUD.

If you've had unprotected sex in the last 5 days and don't want to be pregnant, you can use emergency contraception.

Important emergency contraception fact: You should take emergency contraception as soon as possible after unprotected sex to prevent getting pregnant, as it only works up to 5 days after unprotected sex. If you've had unprotected sex more than 5 days ago, and/or you are late for your period, you will need to take a pregnancy test.

Does emergency contraception protect me against STIs? 

No. Emergency contraception only reduces the chance of you getting pregnant, and won't protect you against STIs. The best way to reduce your risk of STIs is by having safe sex - using barriers such as male condoms, female condoms and dams.

If you've had unprotected sex you should get tested at a sexual health clinic or GUM clinic. 

When should I use emergency contraception? 

You should use emergency contracepetion in these situations:

  • After unprotected sex
  • The condom split or came off
  • Missing pills while taking the combined or progesterone–only pill
  • Being sick or having diarrhoea while taking the combined or progesterone-only pill
  • Being late changing your patch or vaginal ring
  • Being late for your repeat contraceptive injection
  • Forgetting to use a form of contraception
  • Not being able to feel your IUD or IUS threads
  • Taking medicines which reduce the effectiveness of hormonal contraception
  • Following sexual assault or rape  

Emergency contraceptive pill

The emergency contraceptive pill is also known as the 'morning after pill'. 

How does the 'morning after pill' work?

It delays ovulation (release of an egg) and causes some changes to the womb lining, which reduces the chance of pregnancy. It's not the same as the abortion pill as it acts to prevent pregnancy, not terminate an existing pregnancy.

How effective is the 'morning after pill' at preventing pregnancy? 

It prevents up to 85% of unwanted pregnancies and is more effective taken closer to the time of unprotected sex. 

What are the side effects from taking the 'morning after pill'?

The most commonly reported side effects are minor abdominal pain and cramps, as well as some irregular vaginal bleeding. You may experience your period a little earlier or later than usual. If your period is late by more than a few days, you'll need to do a pregnancy test. The morning after pill is not recommended for use in pregnancy, but in the small number of women who become pregnant despite taking it, there is no evidence to date to say that it has damaged the pregnancy.

Will the ‘morning after pill’ interact with my other medications? 

The morning after pill can be made less effective by medications including St. John’s wort and those used for epilepsy. Before taking the pill, you should discuss you medications with a health care provider, or a doctor in the Marie Stopes Health Screening Clinic.

The intrauterine device (IUD)

An IUD is a small T-shaped plastic and copper device that’s inserted into your womb (uterus) by a specially trained doctor or nurse. The IUD may be appropriate if it's less than 5 days since you had unprotected sex. It's the most reliable form of emergency contraception, and may be suitable if you're planning to use an IUD for future contraception. 


How does an IUD work?

 The IUD works by stopping the sperm and egg from surviving in the womb or fallopian tubes. It also prevents a fertilised egg from implanting in the womb. The IUD is a long-acting reversible contraceptive (LARC) method. This means that once it's in place you don't have to think about it each day or each time you have sex. 

You can use an IUD whether or not you've had children.  

How effective is an IUD as an emergency contraceptive?

An IUD is the most effective form of emergency contraceptive. If inserted within 5 days of unprotected sex, it can prevent up to 99.9% of unplanned pregnancy. It's also an effective long acting reversible contraceptive and can be left in for 5 or 10 years depending on which type is used.

Will it hurt to have an IUD put in?

An experienced sexual health doctor will fit your IUD if you choose to have it inserted at Marie Stopes for emergency contraception. A female doctor will be available to answer any questions and discuss your procedure, the risks and benefits. After your discussion, you'll be asked to remove your lower garments and lie on a gynaecological bed. Sometimes we ask for you to put your legs in stirrups as this makes the procedure quicker and easier. 

We'll examine you first to assess the size of your uterus and where your cervix is. We'll then place a speculum in the vagina so we can see your cervix. We'll place a local anaesthetic gel on your cervix and clean the area. We then grasp your cervix with a special instrument, measure the length of the uterus and put in the IUD.

During this part of the procedure, you may experience some discomfort, like a menstrual cramp. Most women tolerate the procedure well and have no issues. If at any stage you are uncomfortable, advise the doctor, so they can ensure you're managing. The procedure is simple and takes less than 10 minutes.

Are there risks to having an IUD inserted?

There is a small risk of infection, and if you have not had swabs done, we may give you antibiotics at the time of the procedure to minimise this. There is also a small risk of a perforation of the uterus and for this reason, we ask you to feel for the IUD strings to ensure the IUD is in place. There's a small increased risk of an ectopic pregnancy when an IUD is in placed. 

Some women find they have some menstrual cramping and spotting after an IUD is inserted. This usually settles in 24-48 hours but if it persists you can contact our 24-hour advice line.

The IUD is the most effective non-hormonal contraceptive available. Some women say they have slightly heavier periods with a copper IUD in place. Most women find it an easy and reliable contraceptive and like the fact that it has no hormonal side effects. If you have not had a period within four weeks of having your IUD inserted for emergency contraception, you will need to do a pregnancy test. If you have any issues after your IUD is inserted please contact our 24-hour advice line.