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Glossary of terms

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 (70/1.75 = 40 and 40/1.75 = 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

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 do not depend on you remembering to take or use them to be effective. 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.


© 2015 Merck Sharp & Dohme Ltd. All rights reserved.

Job code: WOMN-1160817-0000

Date of preparation: September 2015

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