Progestin Only Contraception

Progestin-only contraception is the group of hormonal methods that contain a progestin without oestrogen: daily pills, two-monthly and three-monthly injections, subdermal implants and the levonorgestrel intrauterine device. They suit patients in whom oestrogen is contraindicated or poorly tolerated, including breastfeeding women. Their shared main adverse effect is a change in bleeding pattern, and none protects against sexually transmitted infections or HIV.

Methods and regimens.

Method	Active agent and strength	Route	Interval or duration
Traditional pill	Levonorgestrel 30 microgram	Oral	Daily, no break
Desogestrel pill	Desogestrel 75 microgram	Oral	Daily, no break
Drospirenone pill	Drospirenone 4 mg	Oral	Daily, 24 active then 4 inactive tablets
DMPA intramuscular	Medroxyprogesterone acetate 150 mg	Deep intramuscular	Every 13 weeks
DMPA subcutaneous	Medroxyprogesterone acetate 104 mg	Subcutaneous	Every 13 weeks
Norethisterone enanthate	200 mg	Intramuscular	Every 8 weeks
Etonogestrel implant	68 mg, single rod	Subdermal	3 years
Levonorgestrel implant	75 mg each rod, two rods	Subdermal	5 years (5-year system) or 3 years (other system)
Levonorgestrel intrauterine device	52 mg	Intrauterine	5 years

Mechanism. All thicken cervical mucus and thin the endometrium. Injectables, implants, and desogestrel and drospirenone pills also suppress ovulation consistently. Traditional low-dose pills suppress ovulation in only some cycles, and the levonorgestrel device acts mainly within the uterus.

Effectiveness. First-year pregnancies in 100 women, typical use then perfect use: pills 9 and 0.3; injectables 4 and 0.2; levonorgestrel 52 mg device 0.2 and 0.2; implants 0.05 and 0.05. Pills and injectables lose protection quickly when doses are late.

Return to fertility. Fertility returns at once after stopping pills, implants and the device. After injectables, ovulation may be delayed for four months or longer, and in some patients up to 12 months.

Ideal candidates. Patients who need or prefer an oestrogen-free method: breastfeeding women, smokers, and patients with hypertension, obesity, migraine, valvular heart disease or a history of venous thromboembolism.

Assessment. Take a menstrual, obstetric, breastfeeding and medicine history and measure blood pressure. Pelvic examination, breast examination, routine laboratory tests and cervical screening are not needed before starting. Offer an HIV test as part of routine contact.

Pregnancy exclusion. A patient is reasonably certainly not pregnant if any one of these applies:

Baby under 6 months, fully breastfeeding and no menses since birth.
Delivery within the last 21 days.
No sex since the last normal period.
Within 5 days of the start of a normal period.
Within 5 days of abortion or miscarriage.
Negative pregnancy test and no unprotected sex in the last 3 weeks.
Consistent and correct use of a reliable method.

If none applies, do a sensitive urine pregnancy test. If testing is unavailable, the patient uses condoms or abstains until menses or a test confirms non-pregnancy. When a method is started with backup after a negative test, repeat the test once 3 weeks have passed since the last unprotected sex.

Eligibility categories. Category 1 means no restriction, category 2 means benefits usually outweigh risks, category 3 means risks usually outweigh benefits (use only when no other method is acceptable, clinical judgement is possible and follow up is assured), category 4 means do not use.

Condition	Pills	Injectables
Breastfeeding, under 6 weeks postpartum	2 under 4 weeks, 1 from 4 weeks	3
Current breast cancer	4	4
Past breast cancer	3	3
Acute deep vein thrombosis or pulmonary embolism	3	3
Past deep vein thrombosis or pulmonary embolism	2	2
Ischaemic heart disease or stroke	2	3
Severe decompensated cirrhosis, hepatocellular adenoma, hepatoma	3	3
Unexplained abnormal vaginal bleeding before evaluation	2	3
Lupus with positive or unknown antiphospholipid antibodies	3	3
Rifampicin or rifabutin	3	DMPA 1, norethisterone enanthate 2
Phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine	3	DMPA 1, norethisterone enanthate 2
HIV infection	1	1
Efavirenz, nevirapine or ritonavir-boosted regimens	2	2

Interactions. Rifampicin, rifabutin, enzyme-inducing antiseizure medicines, efavirenz, ritonavir-boosted regimens, griseofulvin and St John’s wort lower pill hormone levels. DMPA effectiveness is not reduced by enzyme inducers.

Counselling. Obtain informed consent, protect confidentiality and exclude coercion. Adolescents under 18 years give assent, and consent follows the law. Do not withhold any method on age alone. Explain bleeding changes, delayed fertility after injectables, and condom use for infection protection.

Method	Start without backup	Start later	Late or missed rule
Traditional pill	Days 1 to 5 of menses	Backup 2 days	Late at 3 hours; backup 2 days
Desogestrel pill	Days 1 to 5 of menses	Backup 2 days	Late at over 12 hours; backup 2 days
Drospirenone pill	Day 1 of menses	Backup 7 days	Late at over 24 hours; backup 7 days
DMPA 150 mg or 104 mg	Within 7 days of menses	Backup 7 days	Up to 4 weeks late without backup
Norethisterone enanthate 200 mg	Within 7 days of menses	Backup 7 days	Up to 2 weeks late without backup

Postpartum. Pills: breastfeeding women from 4 weeks; non-breastfeeding women at once or within 3 weeks. Injectables: breastfeeding women from 6 weeks; non-breastfeeding women at once or within 21 days. Later than that, exclude pregnancy and use backup (2 days for pills, 7 days for injectables).

Postabortion. Pills start at once. Injectables start within 7 days, or later with backup for 7 days.

Switching. Start at once after a hormonal method used correctly. From an injectable to a pill, start when the repeat injection is due. DMPA and norethisterone enanthate are not interchangeable except by switching when the next injection falls due. From an intrauterine device, start in the first 5 days of menses (pills) or 7 days (injectables) and remove the device then; otherwise keep it until the next menses.

Monitoring. Review for bleeding or side effects, with a visit at least once a year for resupply, blood pressure and weight. Community providers may supply up to 3 pill cycles at a time to category 2 users.

Stopping. Remove or stop on request. Offer another method for protection if pregnancy is not wanted.

Expected effects. Irregular, frequent, prolonged or absent bleeding; headache; dizziness; mood change; breast tenderness; acne; weight change. Bleeding change is common and harmless. Amenorrhoea develops in most injectable users within a year.

Heavy or prolonged bleeding. Exclude gynaecological disease and pregnancy first. Then give either:

Ibuprofen 400 to 800 mg orally three times daily with food for 7 to 14 days; maximum 2400 mg in 24 hours. Avoid in peptic ulcer, significant renal impairment, severe liver disease, NSAID-sensitive asthma and the third trimester; acceptable in breastfeeding.
A combined oral contraceptive, one active tablet daily for 1 to 3 cycles, only if oestrogen is not contraindicated and the patient is not breastfeeding under 6 months.

If bleeding stays unacceptable or threatens health, stop the method and change it.

Red flags. Refer or evaluate at once for:

Severe lower abdominal pain: exclude ectopic pregnancy.
Severe or worsening headache, or new migraine with aura.
Calf pain or swelling, chest pain or breathlessness.
Jaundice.
A breast lump.
Bleeding that starts after months of regular or absent bleeding: assess for pregnancy and other pathology.

Referral and escalation. Refer unexplained abnormal bleeding for pelvic examination and cervical screening where available, and refer any pregnancy for antenatal care after stopping the method.

Progestin Only Contraception

Overview And Clinical Pharmacology

Patient Selection And Medical Eligibility

Prescription, Administration And Follow Up

Adverse Effects, Complications And Clinical Management