There may be a number of terms or words used throughout the website that you are not entirely familiar with. Take a look at the glossary of terms below for some helpful guidance.


BMI (Body Mass Index) is a number calculated from your weight and height, and helps you to figure out if you’re a healthy weight for your height.

How do I do it?
Divide your weight in kilograms (kg) by your height in metres (m) then divide this result by your height in metres (m) again. For example, if you weigh 70kg, and you're 1.75m tall, your BMI would be 22.9 (70 divided by 1.75 equals 40 and 40 divided by 1.75 equals 22.9). There are also BMI calculators available online.

Breakthrough bleeding

Breakthrough bleeding, or ‘spotting', is bleeding in between your periods. It can occur especially in the first few months after starting a hormonal method of contraception. If the bleeding does not settle after the first couple of months or if it is heavy or prolonged you should contact your doctor who may wish to investigate the cause of the bleeding further. The bleeding is usually light though a few women may experience heavier bleeding.


The cervix (or neck of the womb) is the lower, narrow portion of the uterus where it joins with the top end of the vagina.

Emergency contraception

Is a contraceptive measure which is used after having unprotected sex, or if a method of contraception has failed. There are two methods of emergency contraception emergency contraceptive pills and the copper intrauterine devices (IUDs).

GUM Clinic

Genito Urinary Medicine (GUM) Clinics are sexual health centres that provide information, testing, contraception and treatment. They are also known as sexual health centres or clinics.

Hormonal contraceptives

Hormonal contraceptives contain hormones that work in a similar way to hormones that occur naturally in your body.

Non-hormonal contraceptives

A general term referring to any method that does not use hormones to work. Non-hormonal contraceptives work either by stopping sperm from fertilising an egg or by preventing a fertilised egg implanting into the lining of the womb.

Long-acting reversible contraception (LARC)

Long-acting reversible contraceptives prevent you from becoming pregnant for long periods of time, usually a number of years, and do not depend on you remembering to take or use them, or on you using them correctly, to be effective. It is important to realise that for any of the methods that last a number of years, they are also fully reversible once stopped. So, if you wish to have a baby they can be stopped at any time if you choose to. Methods include the contraceptive implant, contraceptive injection, intrauterine system (IUS) and intrauterine device (IUD or the 'coil').

Migraines with aura

Migraine with aura is when there is a 'warning sign' or aura before the migraine begins. The warning can include flashes of light or blind spots and difficulty focusing.

Missed pill window

A missed pill window is the time in which you can take a pill each day (combined pill or progestogen-only pill). If you take it outside of this window it is counted as a missed pill and an additional form of contraception may be required for protection against pregnancy to be maintained. The missed pill window depends on the type of pill.


Oestrogen is one of the female sex hormones and helps control your ability to have periods and get pregnant. A synthetic version of oestrogen is included in combined hormonal contraceptives such as ‘the Pill', contraceptive patch and vaginal contraceptive ring.


Women usually have two ovaries, one on each side of their womb. They are small glands that store eggs. Inside the ovaries are hundreds of thousands of pre-eggs, called follicles. Some of these grow into eggs.

Ovarian cysts

An ovarian cyst is a sac of tissue that develops inside an ovary. It is very common, usually painless and will often go away without treatment. Most ovarian cysts are small, benign (non-cancerous) and do not produce any symptoms. Larger cysts may cause problems, such as pain and swelling in your abdomen.


Ovulation is when one or more eggs are released from one of your ovaries. This is the most fertile time of your menstrual cycle, between periods.


Pessaries are a way of delivering medicines and are solid, bullet-shaped preparations designed for easy insertion into the vagina. They can be inserted using your fingers, or may come with an applicator.


Progestogen is the synthetic form of the female hormone progesterone which helps control your ability to have periods and become pregnant. Progestogen is found in all hormonal contraceptives.

Sexually Transmitted Infection (STI)

Sexually transmitted infections (STIs) are infections that are spread primarily through intimate person to person sexual contact. They are also sometimes known as sexually transmitted diseases and there are over 30 sexually transmissible bacteria, viruses and parasites.

Uterus (womb)

The womb, or uterus, is the muscular, pear-shaped organ at the top of the vagina where a baby grows before being born. Intrauterine means ‘inside the uterus’ or womb.

The information on this website is educational only and is not intended to be used for any self-diagnosis purposes nor to replace the advice of your doctor or healthcare professional. Please consult your doctor or healthcare professional for further information on your contraceptive options. This website is intended for use by residents of the Republic of Ireland only. This website is developed and maintained by MSD Ireland (Human Health). See for more information.

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Registered Address: MSD Ireland (Human Health), Red Oak North, South County Business Park, Leopardstown Dublin 18. 
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All people depicted on this site are models and are used for illustrative purposes only.

Job code WOMN-1178118-0000 Date of preparation: July 2016