Ethinyl Estradiol with Levonorgestrel Dosing for Contraception
For routine contraception, use ethinyl estradiol 20-30 mcg combined with levonorgestrel 100-150 mcg daily for 21 days, followed by a 7-day hormone-free interval (or 2 days placebo plus 5 days low-dose ethinyl estradiol), taken at the same time each day to maximize contraceptive efficacy. 1, 2, 3
Standard Contraceptive Regimens
Daily Dosing Options
The most commonly studied and effective formulations include:
Ethinyl estradiol 20 mcg + levonorgestrel 100 mcg: This ultra-low-dose combination demonstrates excellent contraceptive efficacy with a Pearl index of 0.29 (method failure) and 0.88 (overall), with good cycle control and minimal side effects 2, 4
Ethinyl estradiol 30 mcg + levonorgestrel 150 mcg: This slightly higher dose formulation shows a corrected Pearl index of 0.13, representing highly effective contraception with very low failure rates 3
Cycle Regimens
28-Day Standard Cycle 1:
- 21 days of active white tablets (ethinyl estradiol + levonorgestrel)
- 2 days of placebo (light-green inert tablets)
- 5 days of low-dose ethinyl estradiol only (light-blue tablets)
- This provides 4 withdrawal bleeding episodes per year
91-Day Extended Cycle 5:
- 84 days of levonorgestrel 150 mcg/ethinyl estradiol 30 mcg
- 7 days of ethinyl estradiol 10 mcg
- This reduces withdrawal bleeding to 4 episodes per year with a Pearl index of 0.76 (0.26 for method failure)
Initiation Protocols
Sunday Start 1
- Begin first tablet on the first Sunday after menstruation begins
- Use backup contraception for the first 7 consecutive days
- If menstruation begins on Sunday, start that same day
Day 1 Start 1
- Begin first tablet on the first day of menstruation
- No backup contraception needed if started on true Day 1
- More immediate contraceptive protection compared to Sunday start
Missed Pill Management
Critical timing window: The 20 mcg ethinyl estradiol formulations maintain adequate ovarian suppression even when 1-2 pills are missed mid-cycle, though backup contraception is still recommended 6
One Missed White Tablet 1
- Take the missed tablet as soon as remembered
- Continue regular schedule
- No backup contraception needed
Two Consecutive Missed White Tablets (Week 1 or 2) 1
- Take 2 tablets the day remembered
- Take 2 tablets the next day
- Resume 1 tablet daily thereafter
- Use backup contraception for 7 days after missing pills
Two Consecutive Missed Tablets (Week 3) or Three or More Missed Tablets 1
- Sunday Start: Continue taking 1 white tablet daily until Sunday, then discard the pack and start a new pack that Sunday
- Day 1 Start: Discard the current pack immediately and start a new pack that same day
- Use backup contraception for 7 days
Safety Margin and Efficacy
The 20 mcg ethinyl estradiol formulations maintain adequate pituitary-ovarian suppression even with deliberate mid-cycle pill omissions, showing no breakthrough ovulation in controlled studies, though some continued ovarian steroidogenesis occurs 6. This provides reassurance about the safety margin, but existing missed pill instructions should still be followed to ensure maximal contraceptive protection.
Tolerability Profile
Common side effects (generally mild and decreasing over time) 2, 4:
- Headache (17.3% of users, most common reason for discontinuation at 2%)
- Breast tension (11.0%)
- Nausea (7.7%)
- Metrorrhagia (2% discontinuation rate)
Cycle control characteristics 2, 4:
- Intermenstrual bleeding highest in first few cycles, then decreases substantially
- Spotting reported in 12.4% of cycles, breakthrough bleeding in 4.5%
- Absence of withdrawal bleeding occurs in only 2.4% of cycles by cycle 6
- Mean withdrawal bleeding duration: 2 days per cycle with extended regimens 5
Important Clinical Considerations
Postpartum initiation 1:
- May be initiated 4 weeks postpartum in non-breastfeeding women
- Consider increased thromboembolic risk in the postpartum period
- Use backup contraception until 7 consecutive days of white tablets have been taken
Pre-initiation assessment: Rule out pregnancy before starting, as ovulation and conception may occur prior to initiation 1