Combined Hormonal Contraception

Combined hormonal contraception pairs an oestrogen with a progestin to suppress ovulation. It is delivered as a daily pill, a weekly transdermal patch, a vaginal ring worn for 3 weeks in each cycle, or a monthly intramuscular injection.

All four forms are reversible, protect from the first cycle when started correctly, and give no protection against HIV or other sexually transmitted infections. One set of eligibility categories, interactions and warning signs applies across the class.

Classification. By route: oral, transdermal, vaginal or intramuscular. By oestrogen: ethinylestradiol in most pills, the patch and the common ring; oestradiol valerate, oestradiol cypionate, oestradiol or estetrol in selected pills and injectables. By regimen: cyclic, extended or continuous. By progestin: levonorgestrel, norethisterone, norgestimate, desogestrel, gestodene, drospirenone, dienogest, nomegestrol acetate or cyproterone acetate.

Mechanism. Suppression of gonadotropin release stops follicular development and ovulation. The progestin also thickens cervical mucus and thins the endometrium. The hormone-free interval produces a withdrawal bleed, not a true menstruation, and lengthening that interval lets follicles develop and ovulation escape.

Effectiveness. First-year pregnancies out of 100 women:

The risk of pregnancy is greatest when a new pack, patch or ring is started 3 or more days late, or when 3 or more active pills are missed near the start or end of a pack.

Onset of protection. Immediate when pill, patch or ring is started within 5 days of the start of menses, and when the injectable is given within 7 days of the start of menses. Otherwise 7 days of backup contraception are needed.

Duration and return to fertility. Pill, patch and ring protect only while in use, and fertility returns without delay after stopping, so pregnancy is possible in the first cycle. The combined injectable protects for about 30 days from each dose, and fertility returns after an average of about 5 months.

Non-contraceptive effects. Benefits: lighter and shorter menses, less dysmenorrhoea, improvement in endometriosis and polycystic ovary syndrome symptoms, less iron-deficiency anaemia, improvement in acne and hirsutism, lower risk of ovarian and endometrial cancer, and possible protection against symptomatic pelvic inflammatory disease. Harms: venous thromboembolism, arterial events in patients with risk factors, and a small rise in breast and cervical cancer risk with prolonged use that falls after stopping.

Venous thromboembolism. Absolute risk is about 2 in 10,000 woman-years in non-pregnant non-users, 5 to 7 with levonorgestrel, norethisterone or norgestimate, and 9 to 12 with desogestrel, gestodene or drospirenone. Risk is highest in the first year and on restarting after a break of 4 weeks or more, and remains lower than the risk in pregnancy and the postpartum period.

Suitable candidates. Patients from menarche to 40 years, of any parity, with no category 3 or 4 condition, who want a reversible, user-controlled method with a predictable bleeding pattern. Age and parity alone do not restrict use.

History.

• Venous thromboembolism, stroke, ischaemic heart disease and valvular disease
• family history of thrombosis in a first-degree relative
• blood pressure history
• migraine and whether aura occurs
• smoking and age
• diabetes, its duration and complications
• liver and gall bladder disease
• breast cancer
• postpartum and breastfeeding status
• planned surgery with immobilisation
• all current medicines

Examination and investigations. Measure blood pressure and body mass index before starting. Breast examination, pelvic examination, cervical screening, routine blood tests, lipid profile, glucose and thrombophilia screening are not needed before starting when there is no specific indication. A pregnancy test is needed only when pregnancy cannot be excluded by history.

Eligibility categories. Category 1: no restriction. Category 2: benefits generally outweigh risks. Category 3: risks usually outweigh benefits; use only when no other method is available or acceptable and follow up is assured. Category 4: unacceptable health risk.

Interactions. Enzyme inducers lower hormone levels and cause contraceptive failure: rifampicin, rifabutin, phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine, griseofulvin and St John’s wort. Efavirenz, nevirapine and ritonavir-boosted regimens are category 2 and need consistent condom use. Tenofovir, abacavir, zidovudine, lamivudine, emtricitabine, rilpivirine, etravirine, raltegravir and dolutegravir do not reduce effectiveness. Lamotrigine levels fall during hormone use.

Counselling points for the clinician. Confirm consent and the absence of coercion. Give adolescents under 18 years the chance to assent, with consent in line with the law; no combined method is withheld on age alone. Explain the bleeding pattern, the warning signs, the need for condoms against HIV and sexually transmitted infections, and what to do after a missed dose.

Special groups. Adolescents: eligible from menarche; adherence support is needed. Perimenopause: category 2 from 40 years; reassess at each review, and a change to a progestin-only or non-hormonal method at about 50 years is usual practice. HIV: eligible, after the interaction check. Obesity: category 2; counsel on thrombosis risk. Sickle cell disease: category 2. Epilepsy: depends on the antiseizure medicine.

Tuberculosis treatment with rifampicin: a combined method is not advised and medroxyprogesterone acetate 150 mg injectable, a copper device or a levonorgestrel intrauterine system is used. Pills may be supplied by trained non-clinical providers using an eligibility checklist; patients with category 3 or 4 conditions are referred.

Start timing.

• Pill, patch and ring: start on any day if pregnancy is reasonably excluded. Within 5 days of the start of menses needs no backup, and later starts need backup for 7 days.
• Injectable: within 7 days of the start of menses needs no backup. Later starts need backup for 7 days.

Pregnancy exclusion. Pregnancy is reasonably excluded in any of these situations:

• no intercourse since the last menses
• a reliable method has been used correctly and consistently
• menses began within the past 7 days
• the patient is within 7 days of an abortion or miscarriage
• the patient is within 4 weeks of childbirth and not breastfeeding

Otherwise do a pregnancy test. When pregnancy cannot be excluded, a quick start with 7 days of backup is acceptable, and the pills may be issued to begin with the next menses.

Postpartum and postabortion. Not breastfeeding: not before 21 days. Breastfeeding: from 6 months; between 6 weeks and 6 months a combined method is generally avoided. After first or second trimester abortion, start immediately.

Switching. From another hormonal method used correctly, start at once. From an injectable progestin, start when the next injection is due. From an intrauterine device, start within 5 days of the start of menses and remove the device at the same time; if later, remove it at the next menses.

Supply and follow up. Up to 3 cycles may be issued at a visit. Review at about 3 months and then yearly: blood pressure, weight, smoking, new medicines, bleeding pattern and satisfaction. Stop 4 weeks before major elective surgery with prolonged immobilisation and restart 2 weeks after full mobility. Stopping needs no taper.

Expected effects. Nausea, breast tenderness, mild headache, weight and mood change, and spotting or irregular bleeding, mainly in the first 3 months. Amenorrhoea may occur. Nausea is reduced by taking the pill with food or at bedtime.

Serious complications. Venous thromboembolism, stroke, myocardial infarction, hypertension and, rarely, liver tumours and gall bladder disease.

Red flags. Severe abdominal pain, chest pain or breathlessness, severe or new headache, eye problems and severe calf pain. Stop the method at once and arrange urgent evaluation. The method is not restarted after a confirmed venous thromboembolism, stroke or myocardial infarction.

Unscheduled bleeding. Exclude pregnancy, infection, missed doses, interacting medicines and cervical disease. If persistent and unacceptable, give ibuprofen 800 mg orally three times daily for 5 days with food (maximum 2.4 g daily; avoid in renal impairment, active peptic ulcer or significant liver disease; not used in pregnancy). Aspirin is not used. If bleeding persists after 3 months of correct use, change the formulation or method.

When to change method. Development of a category 4 condition, blood pressure of 160/100 or more, migraine with aura, new need for an enzyme-inducing medicine, or unacceptable side effects.

Referral and escalation. Suspected venous thromboembolism, stroke or myocardial infarction needs emergency transfer. Undiagnosed breast lump, unexplained persistent bleeding and cervical lesions need evaluation while the method continues or is paused depending on findings.