The Combined Pill

How does it work?

How reliable is the Pill?

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What are the benefits?

What are the risks?

Reasons to choose a the Pill (or CHC) option

What is Combined hormonal contraception (CHC)?

Will it affect my return to fertility?

Who should not use CHCs

About the Pill


The combined pill (also known as "the Pill") stops ovulation (an egg being released from the ovary each month) and thickens the mucus at the entrance to the womb, making it difficult for sperm to get through.It contains the hormones oestrogen and progestogen.

You get one pack of pills for every 28-day cycle. You have to take one pill per day.  Different formulations exist:

  • 21-day intake (active tablets) + 7 placebo's (inactive tablets)
  • 24-day intake (active tablets) + 4 placebo's (inactive tablets)
  • 26-day intake (active tablets) + 2 placebo's (inactive tablets)

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How reliable is the Pill?


The Pill is highly effective and reliable when you use it correctly! There are various types of combined pills with different advantages, so pick one perfectly suited to your needs after chatting to your healthcare professional.

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What are the benefits of the Pill?


  • It’s one of the most convenient and reliable contraceptive methods for women worldwide.
  • Hormonal pills can help make your periods regular, reduce pelvic cramps, give you lighter and shorter periods, lessen premenstrual symptoms and improve the condition of your skin.
  • It’s easy to use if you have a good technique for remembering to take it each day, like putting your pill packet next to your toothbrush, or setting a daily alarm on your cellphone.
  • Once you stop taking the Pill, fertility returns quickly to the fertility level for your age at the time of discontinuation. Future fertility can never be proved in advance and depends on the woman’s fertility status prior to attempt conception, as well as age.
  • The Pill can reduce the risk of ovarian cancer, cancer of the womb (endometrial cancer) and colorectal cancer

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What is Combined Hormonal Contraception (CHC)?


Combined hormonal contraception is a group name for many different forms of contraception, including the Pill, the ring and the patch.  The reason that it is called "combined hormonal contraception" is that it contains 2 hormones that are combined in the method, an estrogen and a progestogen.  The estrogen and progestogen both play a role in ensuring that you are 99% protected against falling pregnant, and ensuring that your method choice will give you acceptable cycle control.

  • Combined hormonal contraceptives contain two hormones - oestrogen and progestogen – like the natural hormones oestrogen and progesterone in a woman’s body.
  • Until recently, almost all CHCs contained the oestrogen, ethinyloestradiol (EE). A different oestrogen has now been introduced in certain CHCs in the form of oestradiol (valerate).
  • CHCs contain various progestogens, such as cyproterone acetate, drospirenone, dienogest, gestodene, desogestrel, levonorgestrel, norelgestromin, norethisterone and norgestimate.

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Reasons why women choose a combined hormonal contraceptive (CHC) option


  • The oral contraceptive Pill has been used by over 100 million women worldwide for over 50 years.
  • With the Pill, came the freedom to choose when you want to have children, and plan your family.
  • The Pill has a proven efficacy to prevent pregnancy of 99% when used as indicated.
  • The Pill offers shorter, lighter, more regular and less painful menstrual bleeds.
  • Some Pills also offer benefits for moderate acne.
  • Some Pills also offer benefits for pre-menstrual dysphoric disorder (PMDD), the most severe form of PMS.
  • Once you do plan to have a baby, you can rest assured that the Pill was shown in clinical trials to have no effect on return to fertility.
  • Once you've been given a clean bill of health by your doctor, and all contra-indications and risk factors have been excluded, you are ready to start using an oral contraceptive prescribed by your doctor.

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How does it work?


3 mechanisms of action

  • Inhibition of ovulation - CHCs work primarily by preventing the release of eggs from the ovary (i.e. they inhibit ovulation).
  • Thickening of cervical mucous - decreases the ability of the sperm to penetrate through the cervix.
  • Thinning the endometrium (the lining of the uterus) - makes it difficult for implantation to occur.

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How effective are Combined Hormonal Contraceptives (CHCs)?


Effectiveness depends on the user. When no pill-taking mistakes are made, CHCs are more than 99% effective.

With typical use, about 8-9 pregnancies per 100 women using CHCs may occur over the first year.

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Benefits of Combined Hormonal Contraceptives

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Return to fertility of Combined Hormonal Contraceptives




Return to fertility by age group of Combined Hormonal Contraceptives



  • At birth, a baby girl is presumed to have her lifetime supply of about 7 million egg cells.
  • By puberty, only about 250 000 remain. However, fewer than 500 egg cells are released during a woman’s lifetime.
  • CHC use reduces the number of menstrual cycles, which is believed to be the reason for the gynaecological benefits associated with CHC use.

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Weighing up the benefits against the risks


An estimated 100 million women take the Pill and about 80% of women will use it at some time during their reproductive life.  The Pill is one of the most researched medicines currently available, and have given women the freedom to plan their families.

The use of any medicine is associated with risk and it is the role of the doctor to ensure that the benefits of a medicine outweigh the risks associated with its use.

Side effects of Combined Hormonal Contraceptives


  • Common side effects use include nausea, breast tenderness and headache.
  • These side effects are usually mild, transient in nature, and resolve within a few months.
  • More than 80% of women taking some CHCs report no side effects.

Frequencies of side effects reported in clinical trials with an oral contraceptive containing drospirenone/ethinylestradiol

*usually subsides with continued treatment

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  • are allergic to any of the ingredients in the product
  • have of have ever had a disorder affecting the blood circulation, especially those conditions relating to thrombosis (the formation of a blood clot) in the blood vessels of the legs, lungs, heart, brain or other parts of the body.
  • have a history of stroke, angina or chest pain.
  • have a history of migraine accompanied by visual symptoms, speech disability or weakness or numbness in any part of the body.
  • have diabetes mellitus with blood vessel damage.
  • have jaundice (yellowing of the skin) or severe liver disease.
  • have or have had a cancer that may grow under the influence of sex hormones (e.g. of the breast or genital organs).
  • have sever kidney diseas or kidney failure.
  • have or have had a cancer of the liver.
  • are pregnant or think that you may be pregnant.

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What are the risks?


 Some women experience side effects like nausea, breast tenderness, mood swings, changes in sex drive, headaches, bloating, weight gain or bleeding problems. These symptoms vary from woman to woman and depend on the pill taken. Often, they disappear after the first months of use.

The combined pill is associated with an increased risk of blood clots, e.g. leg thrombosis, lung embolism, stroke and heart attack.

The combined pill DOES NOT offer protection against sexually transmitted infections (STIs), so it’s safest to also use a condom if you and your partner haven’t been tested for STIs.

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 About blood clots and CHCs?


Using a combined hormonal contraceptive (a contraceptive pill containing an estrogen and a progestogen) increases your risk of developing a blood clot compared with not using one. In rare cases a blood clot can block blood vessels and cause serious problems.

What are the chances of getting a blood clot?

Non-pregnant women, not using the pill      : 4.4 events in 10,000 women per year
Women using low dose oral contraceptives  : 9.9 events in 10,000 women per year
Pregnant women                                      :  29.1 events per 10,000 women per year

Information about blood clots

  • Blood clots can develop in veins (referred to as a ‘venous thrombosis’, ‘venous thromboembolism’ or VTE)
  • If a blood clot forms in a vein on the leg or foot, it can cause a deep vein thrombosis (DVT)
  • If a blood clot travels from the leg and lodges in the lung it can cause a pulmonary embolism (PE)
  • Very rarely, a clot may form in other veins e.g. in the eye, causing a retinal vein thrombosis
  • Blood clots can form in the arteries (referred to as an ‘arterial thrombosis’, ‘arterial thromboembolism’ or ATE) 
  • If a blood clot forms in an artery of the heart or brain, it can cause a heart attack or stroke, respectivel

Recovery from blood clots is not always complete. Rarely, there may be serious lasting effects or, very rarely, they may be fatal. It is important to remember that the overall risk of a harmful blood clot is small.

How to recognize a blood clot in a vein

You should seek urgent medical attention if you notice any of the following signs or symptoms.

When is the risk of developing a blood clot in a vein highest?

The risk of developing a blood clot in a vein is highest during the first year of taking a combined hormonal contraceptive for the first time. The risk may also be higher if you restart taking a combined hormonal contraceptive after a break of 4 weeks or more. After the first year, the risk gets smaller but is always slightly higher than if you were not using a combined hormonal contraceptive. However, your risk of a blood clot in a vein is lower when you use the pill than if you were pregnant or during the weeks after childbirth.   

Factors that increase your risk of a blood clot in a vein

The risk of a blood clot with the combined hormonal contraceptive is small, but some conditions will increase the risk.

Your risk is higher:

  • if you are very overweight
  • as you get older, particularly above about 35 years
  • if one of your immediate family has had a blood clot in a vein at a relatively early age. In this case you could have a hereditary blood clotting disorder.
  • if you need to have an operation, or are off your feet for a long time due to illness or injury, or you have your leg in a cast
  • if you gave birth less than a few weeks ago
  • long-haul air travel

The risk of developing a blood clot increases the more conditions you have. It is important to tell your doctor if any of these conditions apply to you, even if you are unsure. Your doctor may decide that the combined hormonal contraceptive is not appropriate for you.

How to recognize a blood clot in an artery


Factors that increase your risk of a blood clot in an artery

It is important to note that the risk of a heart attack or stroke from using the combined hormonal contraceptive is very small but can increase:

  • with increasing age
  • if you smoke – when using a combined hormonal contraceptive, you are advised to stop smoking. If you are unable to stop smoking and are older than 35 your doctor may advise you to use a different type of contraceptive
  • if you are overweight
  • if you have high blood pressure
  • if a member of your immediate family has had a heart attack or stroke at a relatively early age
  • if you or someone in your immediate family have high cholesterol or triglycerides
  • if you get migraines, especially migraines with aura
  • if you have a problem with your heart (valve disorder, atrial fibrillation)
  • if you have diabetes

The risk of developing a blood clot increases the more conditions you have.  It is important to tell your doctor if any of these conditions apply to you, even if you are unsure. Your doctor may decide that the combined hormonal pill is not appropriate for you.

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What are my chances of dying from a blood clot?

The risk for VTE in women taking low-dose CHCs is lower than the risk when you are pregnant or shortly after you have given birth.  The risk of dying from a VTE is very small.  VTE may be fatal in 1-2% of cases.

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