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Contraception FAQs with our senior pharmacist

Melanie King: Pharmacy Operations Manager | minute read

As part of the Pharmacy2U contraceptive service, patients will receive helpful advice from one of our pharmacists which is tailored to the patient’s needs and queries. Here you’ll find a wide range of useful information to help familiarise yourself with the contraceptive pill and the options available.

We cover the Progesterone Only Pill, the Combined Oral Contraceptive, how they both work, side effects, the pros and cons of each, what to do if you miss a pill and the risks. We also look at Long-Acting Reversible Contraception.

If you have been prescribed either a combined oral contraceptive (COC) or a progesterone-only pill (POP), please make sure you read the relevant information on this page.

Progesterone Only Pill (POP)

How it prevents pregnancy 

The traditional progestogen-only pill (POP) prevents pregnancy by thickening the mucus in the cervix to stop sperm reaching an egg. 

The desogestrel progestogen-only pill can also stop ovulation. 

The progestogen-only pill needs to be taken every day to work. 

Side effects 

The progestogen-only pill is generally well tolerated and side effects are rare. 

Side effects may include: 

  • acne 

  • breast tenderness and breast enlargement 

  • an increased or decreased sex drive

  • mood changes 

  • headache and migraine 

  • nausea or vomiting 

  • small fluid-filled sacs (cysts) on your ovaries – these are usually harmless and disappear without treatment 

These side effects are most likely to occur during the first few months of taking the progestogen-only pill, but they generally improve over time and should stop within a few months. 

What to do if you miss a pill 

If you forget to take a progestogen-only pill, what you should do depends on: 

  • the type of pill you're taking 

  • how long ago you missed the pill 

  • how many pills you've forgotten to take 

  • whether you've had sex without using another type of contraception in the previous 7 days 

If you're less than 3 or less than 12 hours late taking the pill 

If you're taking a 3-hour progestogen-only pill and are less than 3 hours late taking it, or if you're taking the 12-hour progestogen-only pill and are less than 12 hours late: 

  • take the late pill as soon as you remember, and 

  • take the remaining pills as normal, even if that means taking 2 pills on the same day 

The pill will still work, and you'll be protected against pregnancy – you do not need to use additional contraception. 

Do not worry if you've had sex without using another form of contraception. You do not need emergency contraception. 

If you're more than 3 or more than 12 hours late taking the pill 

If you're taking a 3-hour progestogen-only pill and are more than 3 hours late taking it, or you're taking the 12-hour progestogen-only pill and are more than 12 hours late, you will not be protected against pregnancy. 

What you should do: 

  • take a pill as soon as you remember – only take 1, even if you've missed more than 1 pill 

  • take the next pill at the usual time – this may mean taking 2 pills on the same day (1 when you remember and 1 at the usual time); this is not harmful 

  • carry on taking your remaining pills each day at the usual time 

  • use extra contraception such as condoms for the next 2 days (48 hours) after you remember to take your missed pill, or do not have sex 

  • if you have unprotected sex from the time that you miss your pill until 2 days after you start taking it reliably again, you may need emergency contraception – get advice from your contraception clinic or GP 

  • tell them that you've been taking the progestogen-only pill as this can affect which emergency contraception is best for you to take 

It takes 2 days for the progestogen-only pill to thicken cervical mucus so sperm cannot get through or survive. 

The Faculty of Sexual Health and Reproductive Healthcare recommends using extra contraception for 2 days after you remember to take your pill. 

The patient information leaflet that comes with your pill might say to use condoms for the next 7 days after you remember to take your pill. This is because it takes 7 days for the pill to stop you ovulating. 

You can also read the patient information inside your box of medication for guidance. 

Advantages and disadvantages 

Advantages: 

  • it does not interrupt sex 

  • you can use it when breastfeeding 

  • it's useful if you cannot take the hormone oestrogen, which is in the combined pill, contraceptive patch and vaginal ring 

  • you can use it at any age 

Disadvantages: 

  • you may not have regular periods while taking it – your periods may be lighter, more frequent, or may stop altogether, and you may get spotting between periods 

  • it does not protect you against STIs 

  • you need to remember to take it at or around the same time every day 

  • some medicines, including some (uncommon) antibiotics, can make it less effective 

If taken correctly, it's more than 99% effective. This means fewer than 1 in 100 who uses the progestogen-only pill as contraception will get pregnant in 1 year. 

Sickness and diarrhoea 

If you're sick (vomit) within 2 hours of taking a progestogen-only pill, it may not have been fully absorbed into your bloodstream. Take another pill straight away and the next pill at your usual time. 

If you do not take another pill within 3 (or 12 hours) of your normal time, use additional contraception, such as condoms, for 2 days (7 days for the 12-hour pill). 

If you continue to be sick, keep using another form of contraception, such as condoms, while you're ill and for 2 days after recovering. 

Very severe diarrhoea – 6 to 8 watery poos in 24 hours – may also mean that the pill does not work properly. 

Keep taking your pill as normal, but use additional contraception, such as condoms, while you have diarrhoea and for 2 days after recovering, or 7 days if you're taking a 12-hour pill. 

Speak to a pharmacist, nurse or GP, or call NHS 111 or the national sexual health helpline free on 0300 123 7123, if you're unsure whether you're protected against pregnancy, or if your sickness or diarrhoea continues. 

Risks of taking the progesterone only pill 

Ovarian cysts 

There is a chance you could develop fluid-filled cysts on your ovaries. These are not dangerous and do not usually need to be removed. 

The cysts usually disappear without treatment. In many cases, the cysts do not cause symptoms, although you may experience pelvic pain. 

Breast cancer 

Research is continuing into the link between breast cancer and the progestogen-only pill. 

There is not enough evidence to say for certain that the progestogen-only pill does not increase the risk of breast cancer. 

But if there is any increased risk, it's likely to be very small and disappear with time after you stop taking the progestogen-only pill. 

Ectopic pregnancies 

The risk of any pregnancy is low during use of effective contraception. Of pregnancies that occur during use of the traditional POP, 1 in 10 may be ectopic. 

More information can be found here: 

https://www.nhs.uk/conditions/contraception/the-pill-progestogen-only/ 

Combined Oral Contraceptive (COC)

How it prevents pregnancy 

The pill prevents the ovaries from releasing an egg each month (ovulation). It also: 

  • thickens the mucus in the neck of the womb, so it is harder for sperm to penetrate the womb and reach an egg 

  • thins the lining of the womb, so there is less chance of a fertilised egg implanting into the womb and being able to grow 

Side effects 

Minor side effects include 

  • Mood swings 

  • Nausea 

  • Breast tenderness 

  • Headaches 

These usually settle down in a few months. 

What to do if you miss a pill 

If you miss a pill or pills, or you start a pack late, this can make the pill less effective at preventing pregnancy. The chance of getting pregnant after missing a pill or pills depends on: 

  • when the pills are missed 

  • how many pills are missed 

Find out what to do if you miss a combined pill. 

https://www.nhs.uk/conditions/contraception/miss-combined-pill/ 

You can also read the patient information inside your box of medication for guidance. 

Advantages and disadvantages 

Some advantages of the pill include: 

  • it does not interrupt sex 

  • it usually makes your bleeds regular, lighter and less painful 

  • it reduces your risk of cancer of the ovaries, womb and colon 

  • it can reduce symptoms of PMS (premenstrual syndrome) 

  • it can sometimes reduce acne 

  • it may protect against pelvic inflammatory disease 

  • it may reduce the risk of fibroids, ovarian cysts and non-cancerous breast disease 

Some disadvantages of the pill include: 

  • it can cause temporary side effects at first, such as headaches, nausea, breast tenderness and mood swings – if these do not go after a few months, it may help to change to a different pill 

  • it can increase your blood pressure 

  • it does not protect you against sexually transmitted infections 

  • breakthrough bleeding and spotting is common in the first few months of using the pill 

  • it has been linked to an increased risk of some serious health conditions, such as blood clots and breast cancer 

When taken correctly, the pill is over 99% effective at preventing pregnancy. This means that fewer than 1 in 100 who use the combined pill as contraception will get pregnant in 1 year. 

Serious symptoms: 

You should stop taking the COC and seek medical help urgently if you experience: 

  • calf swelling 

  • heat or pain in the calf 

  • shortness of breath 

  • chest pain  

  • haemoptysis (coughing up blood from the lungs or bronchial tubes) 

You should seek advice if you experience your first ever migraine or develop an aura if you normally suffer from migraines. 

Risks of taking the combined pill 

There are some risks associated with using the combined contraceptive pill. However, these risks are small. 

Blood clots 

The oestrogen in the pill may cause your blood to clot more readily. If a blood clot develops, it could cause: 

  • deep vein thrombosis (clot in your leg) 

  • pulmonary embolus (clot in your lung) 

  • stroke 

  • heart attack 

The risk of getting a blood clot is very small, but your doctor will check if you have certain risk factors before prescribing the pill. 

Cancer 

The pill can slightly increase the risk of developing breast cancer and cervical cancer. It can also decrease the risk of developing womb (uterus) cancer, ovarian cancer and bowel cancer. 

However, 10 years after you stop taking the pill, your risk of breast cancer and cervical cancer goes back to normal. 

Additional information 

If you are immobile or have restricted mobility for an extended period of time (due to travel, surgery or other reasons) you are at increased risk of blood clots. This risk may be further increased with the use of a COC. You should be advised to stop the COC and to switch to an alternative contraceptive method at least 4 weeks prior to planned major surgery or expected period of limited mobility. 

If you are trekking to high altitudes (above 4500m or 14500 feet) for periods of more than 1 week you may be advised to consider switching to a safer alternative contraceptive method. 

Sickness and diarrhoea 

The general advice for people using oral contraceptives is to follow the instructions for missed pills if vomiting occurs within 3 hours of taking your COC or if severe diarrhoea occurs for more than 24 hours. It is advised to consider non-oral contraceptive if diarrhoea or vomiting persist. 

If you vomit within 3 hours of taking the combined pill, it may not have been fully absorbed into your bloodstream. Take another pill straight away and the next pill at your usual time. 

If you continue to be sick, keep using another form of contraception until you've taken the pill again for 7 days without vomiting. 

Very severe diarrhoea (6 to 8 watery poos in 24 hours) may also mean that the pill does not work properly. Keep taking your pill as normal, but use additional contraception, such as condoms, while you have diarrhoea and for 2 days after recovering. 

Speak to a GP or nurse or call NHS 111 for more information, if your sickness or diarrhoea continues. 

Antibiotics 

The antibiotics rifampicin and rifabutin (which can be used to treat illnesses including tuberculosis and meningitis) can reduce the effectiveness of the combined pill. Other antibiotics do not have this effect. 

If you are prescribed rifampicin or rifabutin, you may be advised to change to an alternative contraceptive. If not, you will need to use additional contraception (such as condoms) while taking the antibiotic and for a short time after. Speak to a doctor or nurse for advice. 

More information can be found here: 

https://www.nhs.uk/conditions/contraception/combined-contraceptive-pill/ 

Long-Acting Reversible Contraception

Long-acting reversible contraception (LARC) is the term used for birth control that helps prevent pregnancy after just one treatment. 

There are a few different options to choose from, so you can make sure you use the one that's right for you and your lifestyle. And because they can be reversed at any time, changing your mind about using them isn’t a worry either. This method of contraception is better at preventing pregnancy than oral contraception. 

But remember – while LARC will protect you against pregnancy it will not protect you against sexually transmitted infections (STIs). So it would be sensible to keep using condoms to protect yourself against STIs. 

There are four different types of LARC: 

Contraceptive injection 

This is a simple injection into a muscle on the top part of your bottom. Once done, you don't have to worry about getting pregnant for around 13 weeks.  

Contraceptive implant  

The implant is a small, flexible rod that’s placed under the skin in your upper arm and can be left for up to four years. It works by releasing the hormone progestogen which stops the ovary from releasing an egg and thickens the cervical mucus to make it difficult for sperm to enter the womb.  

Coil with hormones (IUS or LNG-IUD) 

This is a small, T-shaped device that’s placed inside the womb. Once in place, you don’t have to worry about getting pregnant for five years.  

Coil without hormones (Cu-IUD) 

This is a small device that’s inserted into the womb. Once in place you don’t need to worry about getting pregnant for five to 10 years, depending on the type used. The coil stops sperm reaching an egg and can also stop a fertilised egg from implanting. 

Contact your doctor’s surgery or local sexual health clinic to find out more. 

Where to find your local Sexual Health Clinic 

Your nearest sexual health clinic can be found here: 

 https://www.nhs.uk/service-search/find-a-sexual-health-clinic 

Using condoms alongside all forms of contraception is recommended for STI prevention. Further information on how to get free condoms can be found here:  

https://www.nhs.uk/service-search/other-health-services/free-condoms 

For information and advice about sexual health, including contraception and sexually transmitted infections (STIs) please check out this page: 

https://www.nhs.uk/live-well/sexual-health/