What is a suitable oral contraceptive (OC) pill regimen for a woman?

Oral Contraceptive Pill Regimen for Women

For most healthy women seeking contraception, start with a low-dose combined oral contraceptive containing 30-35 μg ethinyl estradiol plus levonorgestrel or norgestimate, taken daily for 21 days followed by 7 hormone-free days. 1

Standard Regimen Selection

First-Line Choice: Combined Oral Contraceptives (COCs)

• Begin with 30-35 μg ethinyl estradiol combined with a progestin such as levonorgestrel or norgestimate 1
• Take one active pill daily at the same time each day for 21 consecutive days 2, 3
• Follow with 7 hormone-free days (or inactive pills) to allow withdrawal bleeding 2, 3
• Start each new pack on the same day of the week 3

Initiation Timing

Day 1 Start (Preferred):

• Begin the first active tablet on Day 1 of menstrual bleeding 2, 3
• No backup contraception needed 3

Sunday Start (Alternative):

• Begin the first active tablet on the first Sunday after menses onset 2, 3
• Use backup contraception (condoms) for the first 7 days 1, 3

Special Population Considerations

When Contraception is Required in High-Risk Patients

For adolescents or young women with premature ovarian insufficiency requiring contraception, 17β-estradiol-based COCs are first choice (17β-estradiol + nomegestrol acetate OR 17β-estradiol + dienogest), with ethinyl estradiol-based COCs as second choice 1. This recommendation stems from the better metabolic and bone health profile of 17β-estradiol in at-risk populations 1.

Adolescents

• Any low-dose pill (≤35 μg ethinyl estradiol) can be used 1
• No gynecologic examination required before prescribing 1
• Prescribe up to 1 year supply at initial visit 1
• Schedule follow-up at 1-3 months to address adherence and side effects 1

Contraindications (Absolute)

Do not prescribe COCs if the patient:

• Is over 35 years old AND smokes 2, 3
• Has severe uncontrolled hypertension (≥160/100 mmHg) 1
• Has migraines with aura or focal neurologic symptoms 1
• Has current or history of thromboembolism or thrombophilia 1
• Has complicated valvular heart disease 1
• Has ongoing hepatic dysfunction 1
• Has diabetes with vascular complications 1

Managing Missed Pills

If ONE pill is missed (<48 hours late):

• Take the missed pill immediately 1
• Continue remaining pills at usual time (even if taking two pills same day) 1
• No backup contraception needed 1

If TWO or more consecutive pills are missed (≥48 hours):

• Take the most recent missed pill immediately; discard other missed pills 1
• Use backup contraception (condoms) for 7 consecutive days 1
• If pills were missed in Week 3 (days 15-21): skip the hormone-free interval and start a new pack immediately 1
• If pills were missed in Week 1 AND unprotected intercourse occurred in previous 5 days: consider emergency contraception 1

Expected Outcomes and Side Effects

Efficacy

• Perfect use: <1% pregnancy rate per year 4
• Typical use: 4-7% pregnancy rate per year 4
• The 150 μg levonorgestrel/30 μg ethinyl estradiol formulation provides excellent contraceptive effectiveness with acceptable bleeding patterns 5

Bleeding Patterns

• Breakthrough bleeding occurs in approximately 6% of cycles 5
• Amenorrhea occurs in <3% of cycles 5
• Approximately 90% of users have cycle lengths of 28 ± 3 days 5
• Withdrawal bleeding duration and amount typically decrease with continued use 6

Serious Risks

• Venous thromboembolism risk increases from 2-10 per 10,000 woman-years to 7-10 per 10,000 woman-years 4
• This risk is still lower than the 10-20 per 10,000 woman-years risk during pregnancy and postpartum 1
• Smoking in women <35 years is NOT a contraindication, though should be discouraged 1

Common Transient Side Effects

• Irregular bleeding, headache, and nausea are most common 1
• Headache occurs in approximately 10% of cycles 5
• Focal migraine headaches require immediate discontinuation 5
• Minor side effects typically decrease with continued use 6

Critical Counseling Points

• Take pills at the same time daily (preferably after evening meal or at bedtime) 2
• COCs do not protect against STIs; condoms should be used for STI prevention 1
• Breakthrough bleeding is a leading cause of discontinuation, which often results in switching to less effective methods or no method, increasing unintended pregnancy risk 7
• Counsel patients about expected bleeding patterns before initiation to improve continuation rates 7