Examples of Low Dose Monophasic Oral Contraceptive Pills
Low dose monophasic OCPs containing 20-35 μg of ethinyl estradiol with a progestin such as levonorgestrel or norgestimate are recommended options for contraception. 1
Common Low Dose Monophasic OCPs
20 μg Ethinyl Estradiol Formulations:
Levonorgestrel 100 μg/Ethinyl estradiol 20 μg (Alesse) 2, 3
- Highly effective with Pearl index of 0.88 (pregnancies per 100 woman-years)
- Good cycle control with decreasing incidence of breakthrough bleeding over time
- Most common side effects: headache (14%) and metrorrhagia (8%)
Gestodene 75 μg/Ethinyl estradiol 20 μg 4
- Effectively inhibits ovulation
- Comparable efficacy to desogestrel-containing OCPs
- May have less bleeding during treatment cycles
Desogestrel 150 μg/Ethinyl estradiol 20 μg 4
- Complete ovulation inhibition in clinical trials
- Similar hormonal suppression profile to gestodene formulations
30-35 μg Ethinyl Estradiol Formulations:
Desogestrel 150 μg/Ethinyl estradiol 30 μg (Marvelon) 5
- Excellent cycle control with decreasing duration of withdrawal bleeding
- Minimal impact on blood pressure during long-term use
- Very reliable with low pregnancy rates
Levonorgestrel/Ethinyl estradiol 30-35 μg 1
- Recommended by many adolescent medicine providers as a starting option
- Well-established safety and efficacy profile
Norgestimate/Ethinyl estradiol 30-35 μg 1
- Commonly used first-line option
- Good balance of efficacy and tolerability
Clinical Considerations
Efficacy
- Low dose monophasic OCPs provide excellent contraceptive efficacy with typical failure rates of 5-9% 6
- Perfect use failure rates are much lower, approaching 0.3% 3
- Efficacy can be compromised by missed pills, particularly when two or more consecutive pills are missed 6
Advantages of Monophasic Formulations
- Consistent hormone levels throughout the cycle
- Simpler regimen compared to multiphasic pills
- Easier to extend cycles or use continuously when needed 1
- Particularly useful for conditions exacerbated cyclically (migraines without aura, epilepsy, irritable bowel syndrome) 1
Safety Considerations
- Low dose OCPs (≤35 μg ethinyl estradiol) increase VTE risk from baseline 1 per 10,000 to 3-4 per 10,000 woman-years 1
- This risk is substantially lower than pregnancy-associated VTE risk (10-20 per 10,000 woman-years) 1
- Contraindicated in women with:
- Severe uncontrolled hypertension
- Complicated valvular heart disease
- Migraines with aura
- Active thromboembolism or thrombophilia
- Complicated diabetes 1
Newer Formulations
- Drospirenone-containing OCPs may have beneficial effects on blood pressure 1
- Natural estrogens (estradiol valerate, estetrol) may have fewer adverse effects on blood pressure than ethinyl estradiol 1
Practical Management
Missed Pill Instructions
- If one pill is missed (<24 hours late): Take immediately and continue regular schedule 6
- If two or more pills are missed (≥48 hours late): 1, 6
- Take most recent missed pill immediately
- Continue regular schedule (may take two pills in one day)
- Use backup contraception for 7 consecutive days
- Consider emergency contraception if unprotected intercourse occurred
Follow-up
- A follow-up visit 1-3 months after initiating OCPs is useful for addressing adverse effects or adherence issues 1
- The CDC recommends prescribing up to 1 year of OCPs at a time 1
Common Side Effects
- Breakthrough bleeding (most common in first few cycles)
- Headache
- Nausea
- Breast tenderness
When selecting a low dose monophasic OCP, consider starting with a 30-35 μg ethinyl estradiol formulation with levonorgestrel or norgestimate for most patients, as these provide reliable contraception with well-established safety profiles. For patients concerned about estrogen-related side effects, 20 μg ethinyl estradiol formulations offer effective alternatives with potentially fewer adverse effects.