Contraception

Introduction

In England and Wales, about 30% of all pregnancies are unintended, and around 20% of all pregnancies end in abortion. [1] [2] In the US, which has one of the highest rates of unintended pregnancy in the developed world, about half of all pregnancies are unintended. Of these, approximately 40% end in abortion. Nearly one third of American women have an abortion at some point in their lives. Although the abortion rate there has declined recently, the gap between the lower rates of unintended pregnancy in wealthy people and higher rates in disadvantaged groups has widened over the past 2 decades. [3] This disparity suggests that there is limited access to contraception for some women and adolescents, and points to the importance of addressing birth control with all patients at risk of unintended pregnancy.

Availability of contraceptives differs between regions, and local guidelines should always be consulted.

Initial counselling

Contraceptive counselling should aim to maximise:

• Efficacy

• Patient satisfaction

• Long-term adherence.

Selecting an appropriate contraceptive method requires a complete medical history, with special focus on ruling out the most common contraindications. The WHO has produced a chart recording the absolute and relative contraindications to the different contraceptive methods. [4]

[WHO medical eligibility chart]

A general discussion about the risks and prevention of sexually transmitted infections forms part of the initial counselling. Because most contraceptives offer no protection from sexually transmitted infections, clinicians should discuss a dual-protection strategy (i.e., condoms plus a second method).

Patients can be reassured that a Pap smear (cervical cytology test) and pelvic examination are not required before starting most contraceptives. [5] [C Evidence] A questionnaire study of US family physicians, obstetricians, and gynaecologists found that about half refuse to prescribe hormonal contraception without a recent pelvic examination; however, for some patients, fear of a pelvic examination (or difficulty in scheduling/affording one) can pose a significant barrier to obtaining contraception. [6]

Patients' social context should be considered when choosing a contraception method. For example:

• A teenager whose parents disapprove of sexual activity may request a method that is easy to conceal

• A working mother who travels often may be unable to remember a daily pill

To maximise adherence, clinicians should honour patients' preferences, prescribing the particular method each patient chooses, unless a contraindication prevents this. However, clinicians should also ensure that patients know their options, with special emphasis on awareness of the highest-efficacy methods. Patients who receive an ample initial supply of their contraceptive are more likely to adhere to treatment. [7]

Online resources are available that present a comparison of effectiveness of different contraceptive methods.

[USAID and WHO: comparing effectiveness of family planning methods]

[Reproductive Health Access Project: contraceptive choices]

Behavioural methods

These methods include:

• Withdrawal

• Periodic abstinence

• Lactational amenorrhoea.

They require no hormones or medications. Their moderate efficacy depends on consistent adherence. The only risks associated with behavioural methods are inconvenience and failure.

Behavioural methods: withdrawal

Withdrawal is 73% to 96% effective for pregnancy prevention (typical to perfect use). This method requires a high level of trust and self-control. The man must be able to recognise the point at which ejaculation is inevitable, and he must withdraw his penis from the vagina before he ejaculates.

Even when performed perfectly, the withdrawal method may fail if there are live sperm in the man's pre-ejaculate. Risk of failure may be reduced if the man urinates before intercourse.

Behavioural methods: periodic abstinence

Periodic abstinence methods are also known as rhythm and fertility-awareness-based methods. These methods are 75% to 88% effective for pregnancy prevention (typical to perfect use). Women predict ovulation by:

• Tracking basal body temperature

• Checking the consistency of cervical mucus

• Charting menstrual cycles on a calendar.

Combining more than 1 predictor increases efficacy. Couples abstain from intercourse or use a barrier method from 5 days before ovulation to 2 days after ovulation.

Behavioural methods: lactational amenorrhoea

Lactational amenorrhoea is 95% to 98% effective for pregnancy prevention (typical to perfect use). To use this method, women must breastfeed exclusively, nursing at least every 4 hours during the day, and at least every 6 hours during the night. Women can continue using this method until 1 of the following events occurs:

• They have their first menstrual period

• They reach 6 months postpartum

• Their infants nurse less often.

Barrier methods

Barrier methods include:

• Male condom

• Female condom

• Diaphragm

• Cervical cap

• Spermicide (nonoxynol-9).

Although barrier methods offer only moderate efficacy for prevention of unintended pregnancy, condoms and spermicide are available without a prescription, and latex/polyurethane condoms protect against HIV and other STDs. Successful use of barrier methods requires consistency and discipline during intercourse. All barrier methods may be used safely during lactation.

Barrier methods: the male condom

The male condom is 85% to 98% effective for pregnancy prevention (typical to perfect use). A new condom must be used each time a couple has intercourse. With proper use, both latex and polyurethane condoms can prevent transmission of HIV and other STDs. Male condoms can also help to prevent early ejaculation.

Adverse effects and disadvantages include:

• Latex allergy

• Loss of sensation

• Inconvenience/interruption of sexual intercourse

• Slippage/breakage.

Barrier methods: the female condom

The female condom is 75% to 95% effective for pregnancy prevention (typical to perfect use). It consists of a lubricated polyurethane pouch that is inserted inside the vagina during sex. A new condom must be used each time a couple has intercourse. With proper use, the female condom can prevent transmission of HIV and other STDs.

Adverse effects and disadvantages include:

• Friction/noise during intercourse

• Loss of sensation

• Inconvenience/interruption of sex

• Slippage/breakage (has a higher risk of slippage than the male condom).

Barrier methods: the diaphragm and cervical cap

The diaphragm and cervical cap are 84% to 94% effective for pregnancy prevention (typical to perfect use). They must be fitted initially and prescribed by clinicians trained in their use. The diaphragm and cervical cap must be filled and coated with spermicide and inserted before intercourse. Subsequent episodes of intercourse within 6 hours require vaginal insertion of more spermicide with an applicator. The diaphragm and cervical cap do not prevent HIV transmission. To use a cervical cap, the woman must be able to locate her cervix accurately.

Adverse effects and disadvantages include:

• Skin irritation

• Increased risk of bladder infection (diaphragm only)

• Possible increase in risk of HIV transmission. There is evidence that frequent use of spermicide (the diaphragm or cap needs to be used with spermicide) does not decrease, and may actually increase, the risk of HIV transmission. [8] [9] [A Evidence]

Barrier methods: spermicide

Spermicide comes in several forms, including gel, sponge, foam, and inserts. All forms are 71% to 85% effective for pregnancy prevention (typical to perfect use). Spermicide must be inserted each time a couple has intercourse. It does not prevent HIV transmission. Adverse effects/disadvantages include:

• Skin irritation

• A possible increase in risk of HIV transmission. There is evidence that frequent use of spermicide does not decrease, and may actually increase, the risk of HIV transmission. [8] [9] [A Evidence]

Hormonal contraception

Hormonal contraception includes:

• Combined oestrogen/progestogen contraception (pills, patch, or vaginal ring)

• Progestogen-only contraception (pill, injection, implant, or progestogen intrauterine device [IUD]).

Combined hormonal contraceptives (oestrogen/progestogen)

Oestrogen/progestogen contraceptives work primarily by suppressing ovulation. They are available in 3 forms:

• Pill

• Patch

• Vaginal ring.

Although contraceptive pills must be taken daily, the patch is applied weekly, and the vaginal ring is inserted monthly.

These contraceptives are moderately effective and well tolerated. In some countries injectable formulations are available. Any formulation is likely to succeed. However, to promote adherence, clinicians should prescribe the type each patient chooses, unless there is a compelling reason to select a different one.

These contraceptives have few major drug interactions. Women who take certain anticonvulsants (including phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine, lamotrigine) may need to take a pill with a higher oestrogen dose or use a non-oestrogen method. [10] [11] Women who take antibiotics may take oestrogen/progestogen contraceptives without concern about decreased efficacy. Most women can begin combined hormonal contraceptives on the day they select the method, regardless of stage of menstrual cycle and whether or not they have had a recent pelvic examination or Pap smear. [12] Quick start algorithms have been developed to guide the practitioner on which steps to take when a woman requests a new birth control method.

[Reproductive Health Access Project: quick-start algorithm]

Contraindications to oestrogen-containing contraceptives

For most women, the benefits of hormonal contraceptives far exceed their potential risks. [13] Oestrogen-containing contraceptives carry a small risk of thromboembolic complications (including stroke and venous thrombosis). [14]

Some of the most common absolute contraindications to oestrogen-containing contraceptives include: [10]

• Migraine with aura

• Smoking: in women aged over 35 years who smoke >15 cigarettes/day

• Ischaemic heart disease, past or current

• Stroke

• Active liver disease: viral hepatitis, cirrhosis, or tumour

• Major surgery with prolonged immobilisation (combined oral contraceptives should be stopped 4 to 6 weeks before such surgery)

• Deep venous thrombosis, past or current

• Hypertension: poorly controlled (systolic >160 mmHg or diastolic >100 mmHg)

• Breast cancer, current (diagnosis ≤5 years ago).

Some of the most common relative contraindications to oestrogen-containing contraceptives include: [10]

• Migraine without aura: in women aged over 35 years or in smokers

• Smoking: in women aged over 35 years who smoke <15 cigarettes/day

• Concurrent treatment with certain anticonvulsants (including phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine, lamotrigine)

• Postpartum: first 3 weeks (if not breastfeeding), first month (if breastfeeding)

• Hypertension: well controlled or moderately well controlled (systolic 140 to 159 mmHg or diastolic 90 to 99 mmHg)

• Breast cancer, more than 5 years in the past.

More detailed information on medical eligibility for oestrogen-containing contraceptives has been produced by the WHO and is available online. [4]

[WHO medical eligibility chart]

Combined hormonal contraceptives: oestrogen/progestogen pills

Oestrogen/progestogen pills come in many formulations, with varying doses of oestrogen and varying types/doses of progestogen. Combined hormonal contraceptives are 92% to 99% effective for pregnancy prevention (typical to perfect use).

Monophasic pills contain fixed doses of oestrogen and progestogen. Multiphasic pills contain varying doses over the course of a 28-day pack. Most packs contain 21 active pills and 7 placebo pills. Withdrawal bleeding usually occurs while women are taking the placebo pills. Some newer products contain fewer placebo pills (e.g., 24 active pills and 4 placebo pills), with the goal of reducing the number of unintended pregnancies that occur when women miss one of the first few pills in a pack.

The most common adverse effects of birth control pills are:

• Spotting

• Nausea.

Most adverse effects improve after the first 2 or 3 cycles, and persistent adverse effects often resolve when a patient changes to a different pill formulation.

Oestrogen/progestogen pills have several non-contraceptive benefits, including: [15]

• Improvement in medical conditions caused or exacerbated by menses (e.g., menorrhagia)

• Improvement in some non-menstrual conditions (e.g., acne)

• Reduction in risk of developing certain conditions (e.g., ovarian cancer). [16]

Fertility returns quickly when women stop taking oestrogen/progestogen pills.

See below for more details.

Combined hormonal contraceptives: oestrogen/progestogen patch

The oestrogen/progestogen patch contains hormones that are absorbed transdermally. The patch is 92% to 99% effective for pregnancy prevention (typical to perfect use).

Each package contains 3 patches. Women apply a new patch each week for 3 weeks, and use no patch during week 4. Because each patch releases adequate hormone levels to last 9 days, women who change their patch 1 to 2 days late do not increase their risk of unintended pregnancy.

The most common adverse effects of the patch include:

• Spotting

• Skin irritation

• Nausea.

Most adverse effects improve after the first 2 or 3 cycles; persistent adverse effects often resolve when a patient changes to a different oestrogen/progestogen formulation.

The patch has several non-contraceptive benefits (see below).

The patch is slightly less effective in women who weigh more than 198 pounds (90 kg). Because the patch causes higher serum oestrogen levels than do low-dose pills and the vaginal ring, it may be associated with a higher risk of thromboembolic complications. However, thromboembolism remains rare among patch users. Fertility returns quickly when women stop using the patch.

Combined hormonal contraceptives: vaginal ring

The vaginal ring contains oestrogen/progestogen hormones that are absorbed through the vaginal mucosa. The ring is 92% to 99% effective for pregnancy prevention (typical to perfect use).

Each package contains 1 ring. Women typically insert a new ring to remain in place for 3 weeks, and take out the ring for the 4th week. Because each ring releases adequate hormone levels to last 35 days, women who change their ring 10 to 15 days late do not increase their risk of unintended pregnancy. Its long duration of action makes the ring particularly amenable to continuous use (extended cycling; using the ring continuously with no ring-free interval). This has several additional non-contraceptive benefits, including decreased blood loss and decrease in PMS symptoms. Women who choose extended cycling can insert a new ring on the same date of each month.

About 2% of women find that the ring is expelled spontaneously. Women can remove the ring (e.g., during intercourse) for up to 3 hours/day without losing contraceptive efficacy. The most common adverse effects of the ring include:

• Spotting

• Increased vaginal discharge

• Nausea.

Most adverse effects improve after the first 2 or 3 cycles; persistent adverse effects often resolve when a patient changes to a different oestrogen/progestogen formulation. The ring has several non-contraceptive benefits (covered below). Fertility returns quickly when women stop using the ring.

Progestogen-only contraceptives

These methods work primarily by thickening cervical mucus. They may also suppress ovulation and make the endometrium less hospitable to implantation. Progestogen-only contraceptives are available in the following forms:

• Pill

• Injection

• Implant

• Progestogen IUD.

The progestogen-only pill is moderately effective; the 3 other progestogen-only methods are highly effective. Once inserted, the implant and IUD do not depend on their user for efficacy.

Progestogen-only methods are well suited to women who cannot take oestrogen (e.g., women who have intolerable oestrogen-related adverse effects or contraindications). Because breastfeeding is a relative contraindication for oestrogen, progestogen-only methods are preferable during lactation as well. [17] Most women can begin the progestogen-only pill, injection, or implant on the day they select the method, whether or not they have had a recent pelvic examination/Pap smear.

[Reproductive Health Access Project: quick-start algorithm]

Progestogen-only contraceptives: progestogen-only pill

The progestogen-only pill comes in monophasic monthly packs without placebo pills. The progestogen-only pill is 92% to 99% effective for pregnancy prevention (typical to perfect use). This method can be used safely during lactation. To maximise efficacy, women must take each pill at the same time daily. Women who take a pill more than 3 hours late should use a back-up method (e.g., any barrier method) for 1 week.

Women may or may not have a monthly menstrual period while taking the progestogen-only pill. Common adverse effects include:

• Spotting (may persist beyond the first few cycles)

• Hair or skin changes

• Headaches

• Depression

• Decreased libido.

Fertility returns quickly when women stop taking the pill.

Progestogen-only contraceptives: progestogen injection

The progestogen injection (also known as DMPA) contains an intramuscular depot formulation of medroxyprogesterone acetate. The progestogen injection is 97% to 99% effective for pregnancy prevention (typical to perfect use). Women receive this injection either in a doctor's surgery or in a self-administered form every 12 to 14 weeks. Progestogen injection lowers the risk of ovarian and endometrial cancer. After 2 or more cycles, many women become amenorrhoeic.

Common adverse effects include:

• Vaginal spotting (most common)

• Weight gain

• Hair or skin changes

• Headaches

• Depression

• Decreased libido.

Progestogen injections cause a temporary decrease in bone density. Bone density stabilises after 2 years of use and returns to baseline levels after the method is discontinued. Progestogen injection users should be counselled regarding diet and exercise to maintain bone health, but they do not require bone density monitoring. Because progestogen levels decline gradually over many months, adverse effects and lowered fertility may persist for months after women stop using this method.

In some countries, injectable norethisterone is available.

Progestogen-only contraceptives: progestogen implant

The progestogen implant is a single-rod contraceptive device inserted subdermally in the upper arm. The implant is 99% effective for pregnancy prevention. It releases etonogestrel for 3 years. It must be inserted and removed by a clinician trained in its use. Non-contraceptive benefits are covered below.

Many women become amenorrhoeic after a few months. Common adverse effects include:

• Vaginal spotting (most common; may persist for years)

• Weight gain

• Hair or skin changes

• Headaches

• Depression

• Decreased libido.

Fertility returns quickly when the implant is removed.

Non-contraceptive benefits for hormonal contraceptives

• Medical conditions caused or exacerbated by menses: conditions in this group often improve with any hormonal contraceptive product (progestogen-only or combined oestrogen/progestogen). However, for additional benefit and enhanced convenience, hormonal contraceptives can be used continuously. This means that women can skip the hormone-free interval of pills or vaginal ring. There is evidence that continuous extended cycling is effective and safe. [18] [B Evidence] However, due to the variety of types of pill used in different trials, it is difficult to make direct comparisons between regimens. [19] Continuous use of hormonal contraceptives provides extra benefit for the conditions below by eliminating menses:

  • Menorrhagia

  • Dysmenorrhoea

  • Premenstrual syndrome

  • Endometriosis

  • Menstrual migraines

  • Irregular menses

  • Iron-deficiency anaemia

  • Menstrual flares of rheumatoid arthritis

  • Coagulation defects (e.g., menstrual porphyria).

• Non-menstrual conditions alleviated by combined hormonal contraceptives:

  • Acne

  • Hirsutism

  • Polycystic ovarian syndrome

  • Perimenopause.

• Risk reduction through use of combined hormonal contraceptives:

  • Ovarian cancer

  • Endometrial cancer

  • Osteoporosis.

  • Colorectal cancer. [20]

Intrauterine devices (IUDs)

IUDs work primarily through prevention of fertilisation. The progestogen IUD also suppresses ovulation and thickens cervical mucus. Two types of IUD are available:

• Copper IUD View image

• Progestogen (progestin) IUD. View image

IUDs are highly effective, well tolerated, long acting, and reversible. For women who intend to delay childbearing by more than 2 years, IUDs are the most cost-effective contraceptive method. IUDs are well suited to women who cannot take oestrogen (e.g., women who have intolerable oestrogen-related adverse effects or oestrogen contraindications). Because the copper IUD also has some post-fertilisation effects, it can be used as emergency contraception up to 5 days after unprotected intercourse. (The progestogen IUD is ineffective for emergency contraception.) IUDs may be used by nulliparous women [21] and those with a past history of sexually transmitted infections. IUDs may be inserted at any point in the menstrual cycle when pregnancy can reasonably be excluded. The risk of uterine perforation must be discussed with all women before an IUD is inserted.

Intrauterine devices: copper IUD

The copper IUD is a non-hormonal contraceptive. It is 99% effective for pregnancy prevention. It remains effective for 10 to 12 years (however, this may differ depending on the brand and country of origin). It often causes heavier, more painful periods during the first few cycles. Less often, it causes irritation of the partner's penis during intercourse; this problem can be addressed by cutting the IUD's string shorter. It can be used as a post-coital method for up to 5 days after the earliest predicted date of ovulation (i.e., day 19 of a 28-day cycle).

Insertion of the IUD carries a transient risk of infection, but after the first few weeks post-insertion the IUD causes no increase in infection risk. Women can be tested for gonorrhoea and chlamydial infection at the time of insertion and as needed thereafter (e.g., for evaluation of symptoms or for screening). If a test is positive, clinicians can safely treat the patient and partner without removing the IUD.

Expulsion is most likely during the first year of use. Expulsion occurs more often in nulliparous women and in women who had the IUD inserted immediately postpartum or post-abortion.

IUD users have a lower risk of ectopic pregnancy than women who are not using contraceptives; however, the few pregnancies that occur with an IUD in place are more likely to be ectopic. [4] [22] [23] Fertility returns quickly when the IUD is removed and is not diminished by past IUD use. [24]

Intrauterine devices: progestogen IUD

The progestogen IUD works primarily through prevention of fertilisation but also suppresses ovulation and thickens cervical mucus. It prevents pregnancy for 5 to 7 years. It is 99% effective for pregnancy prevention. Most women become amenorrhoeic after 6 to 12 months.

Common adverse effects include:

• Spotting, especially during the first few cycles (most common)

• Irritation of the partner's penis during intercourse; this problem can be addressed by cutting the IUD's string shorter

• Bloating

• Nausea

• Headaches

• Breast pain.

Similarly to copper IUDs, insertion carries a transient risk of infection, but after the first few weeks post-insertion the IUD causes no increase in infection risk. Women can be tested for gonorrhoea and chlamydial infection at the time of insertion (without having to wait for the result prior to insertion) and as needed thereafter (e.g., for evaluation of symptoms or for screening). If a test is positive, clinicians can safely treat the patient and partner without removing the IUD. Women with a progestogen IUD have a lower risk of pelvic inflammatory disease than women who use other methods.

Expulsion is most likely during the first year of use. Expulsion occurs more often in nulliparous women and in women who had the IUD inserted immediately postpartum or post-abortion. IUD users have a lower risk of ectopic pregnancy than women who are not using contraceptives; however, the few pregnancies that occur with an IUD in place are more likely to be ectopic. [4] [22] [23] Fertility returns quickly when the IUD is removed, and is not diminished by past IUD use.

Online patient information is available that may help the patient decide which type of IUD is most suitable for them.

[Patient education: IUDs]

Sterilisation

Sterilisation provides permanent, non-reversible protection against pregnancy. Several procedures are available for women and for men. Male sterilisation procedures cost less and carry less risk than female sterilisation procedures.

Sterilisation: female sterilisation

Female sterilisation provides permanent, non-reversible protection against pregnancy. It is 99% effective for pregnancy prevention. It involves cutting, banding, cauterising, or removing the fallopian tubes. Any of these techniques can be performed at the time of caesarean section.

Tubal sterilisation can be performed through a laparoscopic, abdominal, hysteroscopic, or transvaginal approach. Transvaginal sterilisation using the Essure procedure requires no incisions. Essure micro-insert coils are inserted into the uterine end of the fallopian tubes via hysteroscope. Female sterilisation takes effect quickly.

Risks of female sterilisation include:

• Infection

• Bleeding at the time of the procedure.

The risk of post-procedure regret is highest among young women; therefore, young women who request sterilisation should be informed about long-acting reversible methods, such as IUDs. Women who want to become pregnant after sterilisation may have microsurgical repair of their fallopian tubes or they may conceive through in vitro fertilisation.

Sterilisation: male sterilisation

Vasectomy provides permanent, non-reversible protection against pregnancy. It is 99% effective for pregnancy prevention. Vasectomy is performed using local anaesthesia with incision or no-incision ("no-scalpel") techniques.

Risks include:

• Infection

• Bleeding

• Scrotal pain or swelling at the time of the procedure.

Vasectomy does not increase the risk of testicular or prostate cancer. Twelve weeks after vasectomy, men should have a semen analysis to assure the procedure's success. Until a semen analysis demonstrates aspermia, men are advised to use a back-up method of contraception. The risk of post-procedure regret is highest among young men, so young men who request sterilisation should be informed about long-acting reversible methods that may be suitable for their partners, such as IUDs.

Emergency contraception

Emergency post-coital contraception lowers the risk of pregnancy following unprotected intercourse. Advance prescribing increases its use without increasing STIs or sexual risk-taking, even among adolescents. [25]

There are 4 types:

• Progestogen-only emergency contraception: levonorgestrel

• Oestrogen/progestogen emergency contraception

• Copper IUD

• Selective progesterone-receptor modulator (ulipristal).

Online patient information about the different types of emergency contraception is available.

[The emergency contraception website]

[fpa: Your guide to emergency contraception (UK)]

Emergency contraception: progestogen-only emergency contraception

Progestogen-only emergency contraception works primarily by preventing or delaying ovulation. Taken within 72 hours of unprotected intercourse, this method reduces the risk of pregnancy by 89%. This method does not disrupt an implanted pregnancy.

Women may take a single oral dose of levonorgestrel 1.5 mg within 72 hours of unprotected intercourse, or as a dose of levonorgestrel 0.75 mg followed by 0.75 mg 12 hours later. This medication is more effective the sooner it is taken, but it retains some efficacy up to 5 days after unprotected intercourse.

Adverse effects include:

• Nausea

• Spotting

• Change in timing of menstruation.

Guidelines on emergency contraception differ between regions. In the US, progestogen-only emergency contraception is available without a prescription to women aged over 17 years. Girls aged under 17 years must have a prescription. In the UK, emergency contraception can be bought over the counter without a prescription by those aged over 16 years.

Women or girls who vomit less than 2 hours after taking emergency contraception may need to repeat the dose. If needed, antiemetics should be taken 1 hour before emergency contraception.

No particular follow-up arrangement is necessary, unless there is concern about possible pregnancy.

Levonorgestrel has some post-coital effect up to 120 hours after intercourse and is often used off-licence in this way.

Emergency contraception: oestrogen/progestogen emergency contraception

Oestrogen/progestogen emergency contraception works primarily by preventing or delaying ovulation. Taken within 72 hours of unprotected intercourse, this method reduces the risk of pregnancy by 75%. This method does not disrupt an implanted pregnancy. This method causes more nausea than progestogen-only emergency contraception, with similar moderate efficacy. Specific instructions depend on the brand of oral contraceptive used.

Adverse effects include:

• Nausea

• Vomiting

• Spotting

• Change in timing of menstruation.

Women or girls who vomit less than 2 hours after taking emergency contraception may need to repeat the dose. If needed, antiemetics should be taken 1 hour before emergency contraception.

No particular follow-up arrangement is necessary, unless there is concern about possible pregnancy.

Emergency contraception: copper IUD

The copper IUD prevents fertilisation and implantation. It is nearly 100% effective up to 5 days after unprotected intercourse.

Adverse effects include:

• Transient risk of infection

• Heavier, more painful menstrual periods.

This is the most effective emergency contraceptive and is the best method for women who want an IUD for long-term contraception.

Emergency contraception: ulipristal

Ulipristal is a selective progesterone-receptor modulator. It has agonist and antagonist effects on progesterone receptors. Although its mechanism of action is uncertain, it may work by delaying ovulation and through endometrial effects. Taken within 5 days of unprotected intercourse, it reduces the risk of pregnancy by about 90%. [26]

Side effects include headache, dizziness, and abdominal pain. Women who vomit less than 3 hours after taking emergency contraception may need to repeat the dose. If needed, antiemetics should be taken 1 hour before emergency contraception.

No particular follow-up arrangement is necessary, unless there is concern about possible pregnancy.