How to use the combined contraceptive pill correctly plus potential side-effects.
Medically reviewed by Dr Juliet McGrattan (MBChB) and words by Rhalou Allerhand
There are two main types of contraceptive pill: the combined pill and the mini pill. If taken correctly, the combined contraceptive pill is more than 99 per cent effective and you can have sex without the worry of getting pregnant.
The combined pill contains a combination of two hormones similar to those produced naturally by the body; progestogen and oestrogen. For more on the mini pill, read The mini pill – progestogen only pill.
To help you make an informed choice about which of the many different methods of contraception available in the UK to choose from, we look at the combined pill, usage instructions, advantages, disadvantages and potential side-effects:
What is the combined contraceptive pill?
The combined contraceptive pill is often just called the pill. It contains two hormones, an oestrogen and a progestogen which are similar to those released from the ovaries.
There are many different brands of combined contraceptive pills available, the amount of oestrogen and progestogen in the pills varies. Popular brands include Brevinor, Cilest, Femodette, Loestrin, Microgynon, Yasmin.
How does the contraceptive pill work?
The two hormones oestrogen and progestogen in the combined pill override your natural menstrual cycle and work mainly by stopping your ovaries from releasing an egg each month, known as ovulation.
The combined contraceptive pill contains oestrogen and a progestogen, similar to those released from the ovaries.
These hormones also increase the thickness of the natural mucus at the neck of the womb (cervical mucous), making it more difficult for sperm to cross from the vagina into the womb, as well as thinning the womb lining (endometrium), making it more difficult for any successfully fertilised eggs to implant there.
In addition to preventing pregnancy, the combined contraceptive pill is sometimes used to help with symptoms of heavy, painful or irregular periods.
The contraceptive pill dosage instructions
Combined contraceptive pills come in calendar packs marked with the days of the week. The pill is taken at the same time every day for 21 days, followed by a seven-day pill-free break. During the seven-day break, it is usual to get a withdrawal bleed that is similar to your normal period.
You should start your next pack after the seven-day break, even if you are still bleeding.
During the seven-day pill free break, you are still protected, provided that you took all the pills correctly as directed and the effectiveness of the pill was not affected by other medicines, sickness or diarrhoea.
If you want to, you can shorten the seven day break or miss it completely and take two or three packets back to back without a break. This is particularly helpful if you have heavy periods, struggle with mood swings in the break or want to postpone your period because of a holiday or special occasion.
More and more women are taking their combined pills continuously with no breaks at all. Some prefer a withdrawal bleed to confirm they are not pregnant every month but the thinking that women need to ‘flush out’ the womb every month is outdated. Chat to your family planning nurse or doctor if you want to do this.
Some combined pills have 28 tablets in the packet. Seven of these are ‘placebo pills’ with no hormones in them and are just there to make pill taking easier; taking a pill every day rather than counting a seven day break works better for many women. In this situation, if you wanted to miss your bleed you would need to take 21 pills and then miss out the seven dummy pills which are clearly marked on the packet, and go straight onto a new packet.
There are a group of combined pills called ‘phasic pills’. Each pill contains a different amount of hormone to mimic the body’s natural hormone production. It’s important that these are taken in the correct order to prevent pregnancy so talk to your nurse or doctor if you want to avoid a monthly bleed.
How effective is the combined pill?
The effectiveness of any contraceptive is dependent on your age, how sexually active you are and how well you follow the instructions on how to use the contraceptive.
If the combined contraceptive pill is always used perfectly as directed according to the instructions, it is over 99 per cent effective. This means that less than one pill user in 100 will get pregnant in one year.
If the combined contraceptive pill is used perfectly as directed according to the instructions, it is over 99% effective.
If the pill is not always taken or used according to the instructions, for example pills are missed, or you are taking medicines that affect the efficacy of the pill, the risk of pregnancy increases to nine pill users in 100 getting pregnant in one year.
⚠️ If you are sexually active and don’t use any contraception, there’s an 80 per cent chance you will become pregnant within one year.
Is the combined pill right for me?
The combined pill is most suited for healthy women under 35 years of age who don’t smoke. Speak to your doctor to weigh up the risks and benefits of using the pill. Here is a list of conditions that may mean the pill is not suitable for you:
- You are very overweight.
- You smoke and are over 35.
- You have high blood pressure (hypertension).
- You have diabeteswith complications.
- You take certain medications.
- You have had, or your parent, brother or sister has had, a heart attack, strokeor blood clot in the leg (deep vein thrombosis) or lungs (pulmonary embolism) before the age of 45.
- You have a long-term condition called systemic lupus erythematosus (SLE).
- You have unstable Crohn’s diseaseor ulcerative colitis.
- You have active liver or gall bladder disease.
- You have a history of severe migraines, particularly migraines with an aura.
- You have an undiagnosed breast lump or gene mutations that are associated with an increased risk of breast cancer.
- You are immobile for long periods of time or use a wheelchair.
Advantages of taking the combined pill
Taking the pill as a method of contraception may have the following advantages:
- It is more than 99 per cent effective – if used correctly.
- It helps with premenstrual symptoms and can help improve acne in some people.
- It may also help with menopausal symptoms.
- Bleeding during periods becomes more regular, lighter and less painful.
- It can help to control polycystic ovarian syndrome and endometriosis.
- It can reduce the risk of ovarian cancer, cancer in the uterus and colon cancer.
- It may also reduce the risk of fibroids, ovarian cysts and non-cancerous breast disease.
Disadvantages of taking the pill
Taking the pill as a method of contraception may have the following disadvantages:
- It won’t protect you against sexually transmitted infections; you’ll still need to use condomsfor that.
- Breakthrough bleeding, spotting and missed periods can be common in the first few months.
- Side-effects such as headaches, breast tenderness, feeling sick and mood changes are common, but only temporary.
- The pill may increase your blood pressure.
- Increased risk of getting a blood clot, which can cause deep vein thrombosis (DVT), stroke or heart attack are serious but rare side effects. However, the risk is still small. Speak to your GP if you are concerned.
Potential side-effects of the pill
Taking the pill as a method of contraception may have the following side-effects:
- Feeling sick.
- Abdominal pain.
- Breast pain or tenderness.
- Slight bleeding or spotting between periods in the first few months.
- Lighter periods or sometimes stopping of periods.
- Mood changes. However, there’s no evidence that the pill causes depression
- Fluid retention. However, there’s no evidence the pill causes weight gain.
- Rise in blood pressure.
- Skin reactions.
- Change in sex drive.
The pill and blood clot risk
If you experience a serious side-effect or have any concerns about your health, seek medical assistance immediately. Rare but more serious side effects of the contraceptive pill can include:
- Blood clot in an artery
Increased risk of getting a blood clot in an artery, which could cause a stroke or a heart attack. This is called arterial thrombosis. The risk of arterial thrombosis on the pill is higher if you smoke, are overweight, are diabetic or have migraines with an aura.
- Blood clot in a vein
Increased risk of getting a blood clot in a vein, such as a deep vein thrombosis (clot in the leg) or pulmonary embolism (clot in the lungs). The risk of venous thrombosis is higher if you smoke, are overweight, have been immobile for a long period of time or you have a family history of an immediate relative with a thrombosis before the age of 45. Speak to your GP if you are concerned.
- Blood clot symptoms
If you experience symptoms of a blood clot such as stabbing pains and/or unusual swelling in one leg, pain on breathing or coughing, coughing up blood, sudden breathlessness, sudden severe chest pain, migraine or severe headache, sudden disturbance in vision, hearing or speech, sudden weakness or numbness on one side of the body, or if you collapse, stop using the contraceptive pill and see a doctor immediately.