01Purpose and principlesWhat the treatment does and how it fits into care.
Progestogen-only pills thicken cervical mucus; desogestrel and drospirenone formulations also suppress ovulation more consistently than traditional POPs. They require daily use and formulation-specific timing. A traditional norethisterone or levonorgestrel pill is late after three hours, desogestrel after 12 hours and drospirenone after 24 hours. Drospirenone is supplied as 24 active tablets followed by four inactive tablets, so its missed-pill algorithm cannot be substituted for desogestrel rules. Name the product when counselling.
Quick-start rules depend on formulation. A POP started early in a natural cycle may be immediately effective; later starts generally require additional precautions for two days with traditional or desogestrel POPs and seven days with drospirenone, subject to current product guidance and switching context. Following a missed pill, establish lateness, subsequent tablets and intercourse before deciding about emergency contraception. Vomiting soon after a dose or severe diarrhoea may act like a missed tablet.
The etonogestrel implant is a single subdermal rod that suppresses ovulation and thickens mucus. The UK licence was extended in 2026 from three to five years, so use the current replacement interval and document insertion date. Effectiveness exceeds 99% and fertility returns promptly after removal. Confirm the rod is palpable immediately after insertion and teach the patient how to check its location. Deep, migrated, fractured or impalpable implants need trained assessment and imaging, not exploratory removal.
Unscheduled bleeding is the commonest implant problem and does not indicate reduced effectiveness when the device is in date and no interaction exists. Explore the pattern, pregnancy risk, infection symptoms, cervical screening status and medicine changes. Explain that bleeding may be absent, infrequent, frequent or prolonged and remains unpredictable for an individual. If treatment is requested, use a guideline-supported short course selected for eligibility and preferences; removal remains available at any time.
DMPA provides high-dose ovulation suppression. Depo-Provera 150 mg IM and Sayana Press 104 mg SC are administered every 13 weeks; properly supported self-administration of the subcutaneous product may improve autonomy. Typical-use effectiveness is about 94% because late repeat doses occur. DMPA is unaffected by hepatic enzyme induction, but it cannot be removed after injection and adverse effects persist while drug levels decline.
Counselling for DMPA must include bleeding change, possible weight gain, temporary bone-mineral-density loss and delayed fertility return. Fertility may take up to one year to return to its prior level after stopping, which differs from implant and POP. Review ongoing use in adolescents and people with significant osteoporosis risk, and reassess beyond age 45 rather than imposing an arbitrary two-year maximum. Balance bone considerations against pregnancy risk and alternative acceptability.
Across all three methods, use UKMEC for breast cancer, liver disease and major comorbidity. Progestogen-only methods do not carry the same oestrogen-related VTE restrictions, but DMPA may differ from POP or implant in some cardiovascular settings. Reconcile enzyme-inducing antiseizure medicines, rifamycins and St John’s wort: these reduce POP and implant reliability, whereas DMPA and intrauterine methods remain effective. Include STI prevention and a seamless switch whenever a method is stopped.
Key points
- Progestogen-only methods avoid oestrogen and are suitable for many people who cannot use CHC, but current breast cancer and some serious liver or vascular conditions still alter eligibility.
- Know the pill formulation: traditional norethisterone or levonorgestrel POP has a three-hour late window, desogestrel a 12-hour window and drospirenone a 24-hour window with different missed-pill rules.
- The etonogestrel implant is over 99% effective and, following the 2026 UK licence extension, provides contraception for five years; check the actual insertion and replacement date.
- Depot medroxyprogesterone acetate is given every 13 weeks: 150 mg intramuscularly or 104 mg subcutaneously. Effectiveness falls if repeat administration is late.
- Irregular, prolonged or absent bleeding is common with POPs and the implant; it is usually not dangerous but pregnancy, infection, cervical or uterine pathology and interactions still need selective exclusion.
- DMPA can reduce bone mineral density during use and delay return to fertility for up to a year after stopping; discuss this before initiation rather than when pregnancy is later desired.
- Hepatic enzyme inducers can reduce POP and implant effectiveness but do not reduce DMPA effectiveness; intrauterine contraception is also unaffected.
- None of these methods protects against STIs. Provide condom advice, exact start or switch backup, missed-use instructions and a route for troublesome bleeding or removal.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
Three, 12 and 24-hour POP windows are not interchangeable; the active and inactive tablet pattern also determines what action is required.
Failure to feel both ends may reflect deep placement or migration and requires localisation before removal and assessment of contraceptive cover.
Amenorrhoea, spotting, prolonged or frequent bleeding can occur without disease, but a new concerning pattern still deserves focused assessment.
A repeat dose after its accepted interval can allow ovulation to resume, making exact administration and intercourse dates essential.
Ovulation may remain suppressed for months after the final DMPA dose, unlike the rapid fertility return after POP cessation or implant removal.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Pregnancy-risk assessmentFirst step - Why
- Identify emergency contraception, safe initiation and repeat-testing needs after missed or late use.
- Interpretation and limitations
- Use exact doses, injection or insertion dates and intercourse. A negative test soon after exposure needs repetition 21 days after the latest risk.
- 02
Implant palpation and localisation - Why
- Confirm presence and position before relying on, replacing or removing an uncertain implant.
- Interpretation and limitations
- Both ends should be palpable. Use high-frequency ultrasound and specialist pathways for an impalpable device; never attempt blind removal.
- 03
Targeted abnormal-bleeding assessment - Why
- Separate expected method bleeding from pregnancy, infection or genital-tract pathology.
- Interpretation and limitations
- History directs pregnancy testing, STI tests, examination or imaging. Stable longstanding irregular bleeding with no risk feature often needs reassurance rather than broad investigation.
- 04
Medicine interaction review - Why
- Detect reduced POP or implant effectiveness and teratogenic exposure before failure occurs.
- Interpretation and limitations
- Enzyme inducers make POP and implant unsuitable for reliable cover; DMPA, copper IUD and LNG-IUD are not reduced by induction.
- 05
Selective bone-health assessment - Why
- Identify major osteoporosis risks when initiating or continuing DMPA.
- Interpretation and limitations
- Routine DXA is not required for every user. Clinical fracture history, glucocorticoids, eating disorder and other risks determine investigation or specialist advice.
04Treatment approachPreparation, options, escalation and aftercare.
01Method selectionMatch duration and reversibilityFirst stepA patient wants an oestrogen-free hormonal method.+
- 1Compare daily pill timing, a five-year removable implant and a 13-week injection that cannot be withdrawn, including typical effectiveness and privacy.
- 2Apply UKMEC and assess enzyme inducers, bleeding priorities, future pregnancy timing, weight and bone-health factors relevant to DMPA.
- 3Agree the method voluntarily and give exact start, backup, missed-use, replacement or removal information in the product’s own terms.
02Missed protectionReconstruct the timelineA POP is late, an injection overdue or implant duration uncertain.+
- 1Identify the exact formulation and every relevant dose, administration, replacement and intercourse date; do not apply generic mini-pill rules.
- 2Assess emergency contraception and pregnancy testing, then restart, inject or bridge according to current method-specific guidance and pregnancy certainty.
- 3Provide the correct duration of additional precautions and schedule a urine pregnancy test 21 days after the latest at-risk intercourse.
03Bleeding problemExclude causes and preserve choiceIrregular, frequent or prolonged bleeding becomes unacceptable.+
- 1Characterise change, adherence, pregnancy risk, pain, discharge, postcoital bleeding, cervical screening and interacting medicines, then investigate selectively.
- 2Explain expected method-related patterns and offer an eligible evidence-based short treatment where appropriate, including its duration and limitations.
- 3AlternativeContinue, switch or remove the method according to the patient’s preference, ensuring alternative cover and emergency contraception where timing requires it.
04Impalpable rodLocalise before interventionThe patient or clinician cannot confidently feel the implant.+
- 1Advise additional contraception if device presence or duration is uncertain and assess recent intercourse for emergency contraception.
- 2Refer for localisation with high-frequency ultrasound and use radiographic imaging when appropriate for the radiopaque implant.
- 3Arrange removal by a trained service once located and investigate chest migration only when arm imaging fails or symptoms indicate it.
05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.
Desogestrel 75 microgram progestogen-only pill
Take one tablet orally at the same time every day without a pill-free interval; a dose more than 12 hours late is missed and requires the product-specific missed-pill pathway.Check pregnancy, breast and liver eligibility and enzyme-inducing medicines; explain irregular bleeding, vomiting or diarrhoea advice and the need for condoms for STI prevention.
Drospirenone 4 mg progestogen-only pill
Take one active tablet orally daily for 24 days followed by four inactive tablets in each 28-day pack; use its 24-hour missed-pill window and formulation-specific instructions.Avoid uncritical substitution of other POP rules; assess renal, hepatic and adrenal disease, medicines that raise potassium, enzyme induction, pregnancy risk and bleeding acceptability.
Etonogestrel 68 mg subdermal implant
Insert one radiopaque implant subdermally in the upper arm using trained technique; under the current UK licence replace by five years, or remove earlier whenever requested.Confirm immediate palpability, check insertion timing and enzyme inducers, and refer deep or impalpable devices for imaging and specialist removal rather than exploring blindly.
Depot medroxyprogesterone acetate
Administer 150 mg by deep intramuscular injection or 104 mg subcutaneously every 13 weeks, following product instructions and current late-injection guidance.Discuss bleeding, weight, temporary bone-density reduction, delayed fertility return and inability to reverse a dose; reassess cardiovascular and osteoporosis risks and pregnancy status when late.
06Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- Record the exact POP formulation, implant insertion and replacement date, or injection product and administration date; generic labels create unsafe timing advice.
- Review bleeding pattern, pregnancy symptoms, adherence, acceptability and STI needs, escalating pain, postcoital bleeding or other concerning change.
- Reconcile enzyme-inducing, teratogenic and potassium-altering medicines whenever treatment changes and arrange an unaffected method before exposure where possible.
- For an implant, confirm palpability after placement and evaluate any change in location, neurological symptoms or removal difficulty through a trained pathway.
- For DMPA, revisit fertility timing, weight, bone-health risk, age and alternatives periodically, while avoiding an automatic discontinuation rule unsupported by individual risk.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Name the pill
Calling every formulation the mini-pill obscures three different late windows and can convert a correct instruction into contraceptive failure.
The implant now lasts five years
UK licensing changed in 2026; replacement counselling and records should use the current five-year duration rather than the historic three-year interval.
Bleeding does not measure efficacy
Irregular implant or POP bleeding does not itself show that ovulation has returned, although pregnancy and interactions must be assessed when relevant.
An injection cannot be removed
This practical difference matters when uncertain about adverse effects, fertility timing or coercion and should be explained before administration.
DMPA survives enzyme induction
Its high systemic progestogen exposure remains reliable with enzyme inducers, unlike POPs and the etonogestrel implant.
08Common pitfallsFrequent interpretation and management errors.
- 01
Giving one missed-pill rule for traditional, desogestrel and drospirenone progestogen-only pills.
- 02
Telling patients in 2026 that the etonogestrel implant routinely expires after three years.
- 03
Attempting to remove an impalpable implant before imaging has established its location.
- 04
Treating all irregular bleeding as hormonal without checking pregnancy risk, infection features, cervical symptoms and interactions.
- 05
Omitting DMPA’s delayed fertility return or temporary bone-density effect from pre-injection counselling.
- 06
Assuming enzyme induction affects DMPA in the same way that it affects POPs and implants.