Which combined oral contraceptive pill (COC) can be prescribed for breakthrough bleeding in an 18‑year‑old woman using the Nexplanon (etonogestrel) implant, assuming no estrogen contraindications?

Combined Oral Contraceptive for Nexplanon-Related Breakthrough Bleeding

For an 18-year-old with breakthrough bleeding on Nexplanon, prescribe a monophasic combined oral contraceptive containing 30-35 μg ethinyl estradiol with levonorgestrel or norgestimate as first-line therapy. 1, 2, 3

Recommended Formulations

The optimal choice is a 24/4 regimen (24 active pills, 4 placebo pills) containing 30-35 μg ethinyl estradiol combined with either levonorgestrel or norgestimate. 2 This regimen provides:

• Superior endometrial suppression compared to standard 21/7 formulations 2
• Lower rates of breakthrough bleeding due to the shorter hormone-free interval 2
• Better cycle control, particularly important for managing irregular bleeding 2

Alternative acceptable formulations include standard 21/7 monophasic pills with 30-35 μg ethinyl estradiol and levonorgestrel or norgestimate if 24/4 regimens are unavailable. 1, 3 These are considered first-line because they have the lowest effective estrogen dose, relatively low VTE risk, and established safety profiles in adolescents. 3

Initiation Protocol

Start the COC immediately (same-day start) regardless of where she is in her cycle. 4, 1

• If started within 5 days of menstrual bleeding onset: No backup contraception needed 1, 2, 5
• If started more than 5 days after bleeding began: Use backup contraception (condoms) for 7 consecutive days 1, 2, 5

Continue the Nexplanon implant in place—do not remove it. The COC is being added solely to manage bleeding, not to replace contraception. 4

Managing Persistent Breakthrough Bleeding

Counsel the patient that unscheduled spotting or bleeding is common during the first 3-6 months and typically improves with continued use. 1, 2, 6 This is not harmful and does not indicate method failure. 1

If breakthrough bleeding persists beyond 3-4 months or becomes problematic:

1. First-line: Add NSAIDs (ibuprofen 400-600 mg three times daily) for 5-7 days during bleeding episodes 1, 7

2. Second-line: If using an extended/continuous regimen, allow a 3-4 day hormone-free interval to temporarily induce bleeding 1, 7, 8

   • Do NOT do this during the first 21 days of COC use 1
   • Do NOT do this more than once per month 1
   • This approach was shown to be significantly more effective than continuing active pills (P < .0001) 8

3. Before treating persistent bleeding, rule out:

   • Pregnancy 1, 2
   • Sexually transmitted infections 1, 2
   • Medication interactions (especially enzyme-inducing drugs) 6
   • Smoking (increases breakthrough bleeding via estrogen metabolism interference) 6
   • New uterine pathology (polyps, fibroids) 1, 2

Critical Safety Screening

Before prescribing, confirm the patient does NOT have: 2

• Severe uncontrolled hypertension
• Active or chronic hepatic dysfunction
• Complicated valvular heart disease
• Migraines with aura
• History of thromboembolism or known thrombophilia
• Current smoking (not a contraindication at age 18, but increases bleeding risk) 4, 6

Adherence Counseling

Provide clear missed-pill instructions: 1, 5

• One pill missed (<48 hours): Take immediately, continue regular schedule, no backup needed
• Two or more pills missed (≥48 hours): Take most recent missed pill, use backup contraception for 7 days, consider emergency contraception if unprotected intercourse occurred in previous 5 days 4, 5

Emphasize that 7 consecutive hormone pills are needed to prevent ovulation if pills are missed. 1 Non-adherence is the most common cause of breakthrough bleeding with COCs. 6

Recommend adherence strategies: 1

• Cell phone alarms
• Taking pills at the same time daily (preferably after evening meal or bedtime) 5
• Support from a family member

Important Caveats

The COC does NOT provide additional contraceptive protection beyond the Nexplanon—the implant remains the primary contraceptive method. 4 The implant has a failure rate of <0.05%, far superior to COCs. 4

Heavier baseline menstrual flow predicts more breakthrough bleeding during extended regimens. 8 If this patient had heavy periods before Nexplanon, counsel that breakthrough bleeding may take longer to resolve (potentially 3-6 months). 1, 8

Emphasize consistent condom use for STI protection regardless of contraceptive method. 1 This is particularly important in adolescents who have higher STI rates.