Eligibility and Contraindications for Contraceptive Implants

Medical eligibility for implants rests on the safety of a low, continuous dose of progestin without oestrogen. Implants are safe for most patients, including those who cannot use oestrogen, and only current or past breast cancer is an absolute contraindication. The main questions before insertion are pregnancy, unexplained bleeding, active thrombosis, severe liver disease, breast cancer and interacting medicines.

Categories. Category 1: use without restriction. Category 2: advantages generally outweigh theoretical or proven risks; use with follow up. Category 3: risks usually outweigh advantages; use only with clinical judgement when no other method is available or acceptable and follow up is assured. Category 4: unacceptable health risk; do not use.

Pharmacological basis. Progestin-only methods have no meaningful effect on clotting factors, blood pressure or carbohydrate metabolism at implant doses. Concern arises with hormone-sensitive tumours, hepatic metabolism, and enzyme induction lowering progestin levels.

Effectiveness. About 0.05 pregnancies per 100 women in the first year. Duration 3 years for etonogestrel and the 3-year levonorgestrel system, 5 years for the 5-year levonorgestrel system.

Category 1 conditions.

• Any age from menarche, any parity, smoking at any age.

• Non-breastfeeding postpartum at any time; postabortion after first or second trimester or septic abortion.

• Past ectopic pregnancy, past pelvic surgery.

• Obesity with BMI 30 kg/m2 or more.

• Hypertension, including blood pressure 140 to 159 systolic or 90 to 99 diastolic, and past hypertension in pregnancy.

• Family history of venous thromboembolism, surgery without immobilisation, varicose veins, superficial thrombophlebitis.

• Valvular heart disease, complicated or uncomplicated.

• Non-migrainous headache, depressive disorders, epilepsy without enzyme inducers.

• Endometriosis, fibroids, benign breast disease, family history of breast cancer, endometrial or ovarian cancer, gestational trophoblastic disease.

• Current or past pelvic inflammatory disease, STIs, HIV at any stage, tuberculosis, malaria, schistosomiasis.

• Thyroid disease, mild compensated cirrhosis, viral hepatitis, pregnancy-related cholecystitis, history of gestational diabetes.

• Anaemia, sickle cell disease, thalassaemia.

• Nucleoside reverse transcriptase inhibitors, etravirine, rilpivirine, raltegravir, dolutegravir; most antibiotics, antifungals and antiparasitics.

Category 2 conditions.

• Breastfeeding under 6 weeks postpartum.

• Multiple arterial cardiovascular risk factors; blood pressure 160 systolic or 100 diastolic or more; hypertension with vascular disease.

• Past deep vein thrombosis or pulmonary embolism; established on anticoagulation; major surgery with prolonged immobilisation.

• Initiation with past or current ischaemic heart disease or stroke.

• Systemic lupus erythematosus with severe thrombocytopenia or on immunosuppression.

• Migraine without aura; migraine with aura at initiation.

• Irregular, heavy or prolonged vaginal bleeding patterns.

• Cervical intraepithelial neoplasia or cervical cancer awaiting treatment; undiagnosed breast mass.

• Diabetes without vascular disease; gallbladder disease; focal nodular hyperplasia.

• Efavirenz, nevirapine, ritonavir and ritonavir-boosted atazanavir, lopinavir or darunavir.

• Rifampicin or rifabutin; phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine.

Category 3 conditions.

• Current deep vein thrombosis or pulmonary embolism, at initiation and continuation.

• Ischaemic heart disease or stroke developing during use (continuation).

• Migraine with aura that develops or worsens during use (continuation).

• Severe decompensated cirrhosis; hepatocellular adenoma; malignant hepatoma.

• Unexplained vaginal bleeding suspicious for serious disease, before evaluation; reassess the category once a cause is found.

Category 4 condition.

• Current breast cancer or history of breast cancer.

Not contraindications. Nulliparity, adolescence, HIV, obesity, smoking, hypertension, diabetes without complications, sickle cell disease, and history of ectopic pregnancy do not prevent implant use. Weight, blood pressure and laboratory tests are not prerequisites.

Applying eligibility at the visit. Screen for pregnancy, breast cancer, current venous thromboembolism, severe liver disease, unexplained bleeding and current medicines. If none applies, the patient can have an implant on the same day.

Category 2 patients. Insert and give a clear return plan for the relevant concern, for example new leg swelling in a patient with past thrombosis, or condom use and medicine review in a patient on an enzyme inducer.

Category 3 patients. Document the reason other methods are unsuitable, the patient's informed choice, and the follow up plan. Prefer a nonhormonal method (copper IUD) where suitable.

Regimen reminders.

• Etonogestrel 68 mg rod: replace at 3 years.

• Levonorgestrel two 75 mg rods: replace at 5 years (5-year system) or 3 years (3-year system).

• Insert within 7 days of the start of bleeding for immediate protection; later, exclude pregnancy and use backup 7 days.

Interacting medicines. With rifampicin, rifabutin, efavirenz, nevirapine, boosted protease inhibitors or enzyme-inducing antiseizure medicines, advise condoms for the duration and for 28 days after stopping, or offer DMPA, copper IUD or levonorgestrel IUD. Review medicines at every contact.

Special groups. Adolescents: no restriction; assent and consent in line with the law. Breastfeeding: implant insertion from immediately postpartum. Perimenopause: may continue until menopause. HIV: preferred antiretroviral regimens based on dolutegravir do not interact. Sickle cell disease: implants are suitable.

New conditions during use.

• Venous thromboembolism: treat the thrombosis; the implant may stay (category 3 for continuation) with anticoagulation; discuss removal and alternatives.

• Ischaemic heart disease or stroke during use: remove and change method unless no alternative is acceptable.

• Migraine with aura that starts or worsens: remove and offer a nonhormonal method.

• Breast cancer diagnosis: remove the implant and offer a copper IUD or barrier method.

• Severe liver disease or hepatic tumour: remove and offer a nonhormonal method.

• Jaundice: assess liver function; remove if acute hepatocellular disease or tumour is found.

Unexplained bleeding. New, persistent or post-coital bleeding needs pregnancy testing, cervical inspection, STI testing and pelvic assessment; do not attribute it to the implant without evaluation.

Red flags. Leg swelling, chest pain, sudden severe headache, new focal neurological symptoms, breast mass, jaundice, heavy bleeding with anaemia.

Referral and escalation. Refer suspected venous thromboembolism, stroke or acute coronary syndrome urgently. Refer breast masses and hepatic tumours for diagnosis.