Side effects are the commonest reason for discontinuing a method. Many are harmless and improve with time, but patients who are not warned or treated stop their method and may become pregnant. Counselling before the method is chosen, a plan for side effects, and a ready switch to another method are central. Switching must keep protection continuous.

Approach. Take a history of the effect, exclude pregnancy and serious disease, treat or reassure, and offer a switch when the effect is unacceptable.

Pregnancy exclusion. Reasonably certain if no intercourse since last menses, consistent use of a reliable method, within 7 days of the start of menses, within 4 weeks postpartum, or fully breastfeeding amenorrhoeic under 6 months postpartum. Otherwise test.

Danger signs. Abdominal pain, chest pain or shortness of breath, severe headache, eye problems and severe calf pain.

Assessment. Distinguish expected effects from effects needing evaluation: pregnancy, infection, thromboembolism, new migraine with aura, hypertension, breast mass, abnormal bleeding.

Common effects and first-line management.

Effect	Management
Nausea and dizziness (combined pill)	Assess for pregnancy, reassure, take with meals or at bedtime
Spotting	Assess for pregnancy, reassure, check adherence; if unacceptable ibuprofen 800 mg orally three times daily with food for 5 days, maximum 2.4 g daily
Heavy or prolonged bleeding	Exclude gynaecological disease; ibuprofen 800 mg three times daily for 5 days, or tranexamic acid 500 mg three times daily for 5 days, or a combined pill for 21 days where eligible
Amenorrhoea	Exclude pregnancy, reassure
Headache	Check blood pressure; mild: paracetamol 1 g every 6 hours, maximum 4 g daily; migraine with aura: stop combined method
Breast tenderness	Assess for pregnancy, reassure, give analgesic, refer a breast mass
Mood change	Counsel; if worse, change method
Abdominal pain	Exclude ectopic pregnancy, infection and device problems

Switching rules, to maintain protection.

From	To	Rule
Another hormonal method	Combined pill, progestin-only pill, implant, injectable	Start at once if the previous method was used consistently and correctly, or pregnancy is excluded; if the previous method was an injectable, start when the next injection is due
Nonhormonal method (not an intrauterine device)	Combined pill	Start within 5 days of menses; later if reasonably certain not pregnant with 7 days of backup
Nonhormonal method	Progestin-only pill	Within 5 days of menses; later if pregnancy excluded with 2 days of backup
Nonhormonal method	Injectable or implant	Within 7 days of menses; later if reasonably certain not pregnant with 7 days of backup
Intrauterine device	Hormonal method	Within 7 days of menses (5 days for pills): start and remove the device, no backup. Later: start the method and remove the device at the next menses, or remove at once with backup for 7 days (2 days for progestin-only pills) if not sexually active since last menses
Intrauterine device	Nonhormonal method	Start the method at the next sexual contact after removal
Any method	Intrauterine device	Insert at once if pregnancy is excluded, no need to wait for menses
DMPA	Norethisterone enanthate or reverse	Switch at the time the next injection is due

Instructions after removal of the previous method. Give condoms during any gap.

Interventions to improve continuation. Pre-method counselling about expected effects, follow up within 3 months, a plan for bleeding changes, and an open return policy.

Method changes by effect.

Bleeding unacceptable and persistent: switch from a copper device to a levonorgestrel device or progestin-only method; or from an injectable to another method.
Migraine with aura on a combined method: stop at once and use a method without oestrogen.
Mood change: stop the suspect method after review and switch.
Weight or acne complaint: counsel, then switch if unresolved.

Managing Contraceptive Adverse Effects and Method Switching

Clinical Context And Assessment

Evaluation And Differential Diagnosis

Management And Regimens

Follow Up, Method Decisions And Escalation