Contraception methods: effectiveness and side effects

Contraception methods differ in how they work, how often they are used, how well they prevent pregnancy and what they can change in the body. The NHS describes them across a set of pages, and this guide brings together what those pages say: the methods themselves, how well each one works, how each is used, side effects and risks, effects on periods, and emergency contraception. Every source is listed at the end. It is general information, not medical advice, and it cannot speak to your own situation. For that, a doctor, a nurse, a pharmacist or a sexual health service is the right place to ask.

The main types of contraception

The NHS says that choosing a method can depend on what matters to the person. It lists five things to think about: how well a method works at preventing pregnancy, how it is used, the side effects and risks of hormonal methods, the side effects and risks of non hormonal methods, and the effects on periods. This guide follows the same five points, after a first look at the methods themselves.

Method	What it is
Combined pill	A pill that contains two hormones
Mini pill (progestogen only pill)	A pill that contains one hormone
IUD (copper coil)	A device placed in the womb, with no hormones. It can also be used as emergency contraception
IUS (hormonal coil)	A device placed in the womb that releases one hormone
Contraceptive implant	Placed under the skin of the arm, where it releases one hormone
Contraceptive injection	An injection that contains one hormone
Contraceptive patch	A sticky patch worn on the skin that releases two hormones
Vaginal ring	A soft, flexible ring placed in the vagina that releases two hormones
Condoms	Worn on the penis, to help prevent pregnancy and sexually transmitted infections (STIs)
Internal condoms	Placed in the vagina before sex, to help prevent pregnancy and STIs
Female sterilisation	A procedure that permanently stops eggs meeting sperm
Vasectomy	A procedure that permanently stops sperm being released during sex
Diaphragm or cap	Placed in the vagina before sex, to stop sperm getting into the womb
Natural family planning	Includes tracking the menstrual cycle to avoid sex at the most fertile times
Emergency pill	Taken within 3 or 5 days after sex, depending on the type of pill

Some methods contain two hormones, some contain one and some contain none, and the sections on side effects and risks come back to this split. Condoms and internal condoms are covered in more detail in safer sex basics.

How well each method works

According to the NHS, some methods are more effective than others, and its table gives two figures for each one.

Perfect use

Using the method correctly all the time

Typical use

Using the method without getting it perfectly right all the time, for example missing a pill, a condom coming off during sex or forgetting to replace a vaginal ring

Method	Typical use	Perfect use
Contraceptive implant	Over 99%	Over 99%
IUS (hormonal coil)	Over 99%	Over 99%
IUD (copper coil)	Over 99%	Over 99%
Contraceptive injection	94%	Over 99%
Combined pill	91%	Over 99%
Mini pill	91%	Over 99%
Contraceptive patch	91%	Over 99%
Vaginal ring	91%	Over 99%
Condoms	82%	98%
Internal condoms	79%	95%
Natural family planning	76%	91 to 99% (estimate)
Diaphragm or cap	Not known	92 to 96% (estimate)

The NHS gives an example. The implant is over 99% effective when used correctly all the time, which means that if 100 women chose it, fewer than 1 would have an unintended pregnancy within the first year of use. The NHS marks the perfect use figures for natural family planning, diaphragms and caps as estimates, and it gives no typical use figure for diaphragms and caps.

The three methods at the top of the table, the implant and the two kinds of coil, are all given by a doctor or a nurse and last for years, as the next section shows.

How often each method is used

The NHS sorts methods by how often they need to be used.

How often	Methods
Every time you have sex	Condoms, diaphragm, cap
Every day	Combined pill, mini pill
Every week	Contraceptive patch
Every 3 weeks	Vaginal ring
Months or years	IUD, IUS, implant, injection
Permanent	Vasectomy, female sterilisation

For the methods that last months or years, the NHS gives these durations:

• IUD (copper coil): 5 or 10 years, depending on the type.
• IUS (hormonal coil): 3 or 6 years, depending on the type.
• Contraceptive implant: 5 years.
• Contraceptive injection: 8 to 13 weeks, depending on the type.

Who gives or uses the method also differs. The NHS says you can use or take some methods yourself after an initial appointment with a doctor, a nurse or a pharmacist: the combined pill, the mini pill, the patch, condoms, the diaphragm, the cap and the vaginal ring. With the IUD, the IUS, the implant and the injection, a doctor or a nurse needs to give the method.

Timing around sex differs too. A condom goes on immediately before sex, and a diaphragm or cap can go in a few hours before. With the other methods, the NHS says you do not need to remember them every time you have sex.

Contraception and periods

Some types of contraception can affect periods, making them lighter, heavier, more painful or less painful, the NHS says. It adds that a person with heavy or painful periods may be offered a method of contraception for that reason, even if she does not need contraception to prevent pregnancy.

• Less painful periods. The combined pill, the IUS, the implant and the injection can help.
• Heavy periods. The combined pill, the IUS, the mini pill, the implant and the injection can help. The NHS says the IUS is generally the most effective type of contraception for this.
• Heavier and more painful periods. The IUD (copper coil) can have this effect, and the NHS says it usually gets better within a few months. If the side effects are a problem, the IUD can be removed, and the doctor’s practice or sexual health clinic that fitted it can advise.

Hormonal contraception: side effects and risks

The NHS describes hormonal methods in two groups. The combined pill, the patch and the vaginal ring contain two hormones. The mini pill, the IUS, the implant and the injection contain one.

Side effects. Commonly reported side effects of hormonal contraception include headaches, feeling sick, mood swings, weight gain, sore breasts and acne. The NHS says there is not enough evidence to show whether hormonal contraception causes these side effects. If they appear, they usually get better within around 3 months. Hormonal contraception can also change periods. If side effects are a problem, the NHS says to contact the doctor’s practice or the sexual health clinic where the contraception was obtained, because a different type may suit better.

Risks. The NHS says hormonal contraception can raise the risk of blood clots and breast cancer. The risk is very low, but it means that some hormonal contraception is not suitable for everybody. A doctor, a nurse, a sexual health clinic or a pharmacist can say more about these risks.

Hormonal contraception also comes up in changes in sex drive, which looks at what health services say about desire over time.

Non hormonal contraception: side effects and risks

The NHS lists condoms, the IUD, the diaphragm and the cap as non hormonal methods, and notes that condoms also help prevent STIs. Side effects depend on the method.

• IUD (copper coil). It can cause pain in the lower abdomen or back for a few days after it is fitted. It can also make periods heavier or more painful, which usually gets better after a few months.
• Diaphragm or cap. The spermicide that goes with it can irritate the vagina, and a urinary tract infection such as cystitis may be more likely.

Risks. The NHS names a small risk of infection after an IUD is fitted. It also names a rare risk that the IUD fails and pregnancy happens, in which case there is an increased risk of an ectopic pregnancy.

Contraception and sexually transmitted infections

The NHS says only condoms can protect against STIs, including HIV. Its list describes both condoms worn on the penis and internal condoms as helping prevent pregnancy and STIs.

The NHS also mentions PrEP, short for pre exposure prophylaxis. A person at high risk of getting HIV may be able to use PrEP, a tablet taken to prevent HIV infection, and the NHS notes that it does not prevent pregnancy. The guide to STI testing explains what a visit to a clinic involves.

Emergency contraception

Emergency contraception can stop a pregnancy after unprotected sex, the NHS says: sex without contraception, or sex when contraception might have failed. It needs to be used within 3 to 5 days of unprotected sex, and the sooner it is used, the more effective it usually is.

Type	Time limit
IUD (copper coil)	Fitted within 5 days (120 hours) after sex
Emergency pill, first type	Taken within 3 days (72 hours) after sex
Emergency pill, second type	Taken within 5 days (120 hours) after sex

The NHS calls the IUD the most effective type of emergency contraception. It is a small T shaped device that a specially trained nurse or doctor places in the womb, and an appointment is needed, usually at a sexual health clinic or a doctor’s practice. It can be left in as the usual method of contraception, and it then lasts 5 or 10 years, depending on the type.

For the emergency pill, the NHS names the two main types and gives their brand names. This site does not repeat medicine names, so the NHS page listed at the end is the place to find them.

Where to get contraception and advice

The NHS lists sexual health clinics, also called family planning or contraception clinics, some doctors' practices and most pharmacies as places to get contraception, emergency contraception included. For emergency contraception in particular, it says most sexual health clinics and most doctors' practices can provide the emergency pill or an IUD, and most pharmacies can provide the emergency pill.

When to get help

The NHS points to a doctor, a nurse, a pharmacist or a sexual health clinic in these situations:

• Side effects of hormonal contraception are a problem. A different type of contraception may suit better.
• Side effects of an IUD are a problem. It can be removed, and the practice or clinic that fitted it can advise.
• You want to know more about the risks of hormonal contraception.
• You have had unprotected sex, or your contraception may have failed. Emergency contraception works best the sooner it is used.

Safer sex basics covers what the NHS advises if a condom splits or comes off.

Questions about contraception methods

Which contraception method works best?

In the NHS table, the implant and the two kinds of coil come first, each at over 99% with typical use and with perfect use. Condoms are at 82% with typical use. The NHS says contraception is less effective when it is not used perfectly all the time. Which method suits a person depends on her own health, so that question belongs with a doctor, a nurse or a pharmacist.

How long does each method last?

It ranges from weeks to years. The NHS gives 8 to 13 weeks for the injection, 5 years for the implant, 3 or 6 years for the IUS and 5 or 10 years for the IUD, depending on the type. The pill is taken every day, the patch is changed every week and the vaginal ring every 3 weeks. Sterilisation and vasectomy are permanent.

Does contraception protect against STIs?

The NHS says only condoms can protect against STIs, including HIV. PrEP can help prevent HIV infection, and the NHS notes that it does not prevent pregnancy.

Can contraception help with heavy or painful periods?

The NHS says some methods can. The combined pill, the IUS, the implant and the injection can help make periods less painful, and the same methods plus the mini pill can help with heavy periods. The IUD (copper coil) can have the opposite effect, which usually gets better within a few months.

Does hormonal contraception cause weight gain?

The NHS lists weight gain among the commonly reported side effects of hormonal contraception, but it also says there is not enough evidence to show whether hormonal contraception causes them. If side effects appear, they usually get better within around 3 months.

How soon should emergency contraception be used?

The NHS says within 3 to 5 days of unprotected sex, and the sooner the better. An IUD can be fitted within 5 days (120 hours). One type of emergency pill must be taken within 3 days (72 hours) and the other within 5 days (120 hours).