What are the guidelines for using progesterone-only oral contraceptive pills (OCPS)?

Progestin-Only Oral Contraceptive Pills (POPs)

Progestin-only pills are effective contraceptives that can be started immediately at any time if pregnancy is reasonably excluded, require backup contraception for 2 days after initiation, and are suitable for women of all ages including those with contraindications to estrogen-containing contraceptives. 1

Efficacy and Mechanism

• POPs have a typical-use failure rate of approximately 9 pregnancies per 100 women in the first year of use 1
• POPs inhibit ovulation in only about half of cycles, with rates varying widely by individual 1
• The primary contraceptive mechanism relies on cervical mucus thickening, which requires approximately 48 hours of consistent use to achieve full effect 1
• Peak serum steroid levels occur about 2 hours after administration, followed by rapid elimination such that levels return near baseline by 24 hours 1
• Taking POPs at approximately the same time each day is critical for efficacy due to this rapid pharmacokinetic profile 1

Initiation Guidelines

Timing of Initiation

• POPs can be started at any time if it is reasonably certain the woman is not pregnant 1
• If started within the first 5 days since menstrual bleeding began, no additional contraceptive protection is needed 1
• If started >5 days since menstrual bleeding started, the woman needs to abstain from sexual intercourse or use backup contraception for the next 2 days 1

Postpartum Initiation

• POPs can be started immediately postpartum (≥21 days), including in breastfeeding women 1
• Women ≥21 days postpartum whose menstrual cycles have not returned need backup contraception for 2 days 1
• This represents a significant advantage over combined oral contraceptives, which are not recommended in breastfeeding women during the initial 6 months 2

Postabortion Initiation

• POPs can be started within the first 7 days postabortion, including immediately 1
• Backup contraception is needed for 2 days unless POPs are started at the time of surgical abortion 1

Switching from Another Method

• POPs can be started immediately when switching from another contraceptive method without waiting for the next menstrual period 1
• If >5 days since menstrual bleeding started, backup contraception is needed for 2 days 1
• When switching from an IUD, consider retaining the IUD for at least 2 days after POP initiation, or advise abstinence/barrier contraception for 2 days before IUD removal 1

Pre-Initiation Requirements

No examinations or tests are required before initiating POPs in healthy women 1

• Blood pressure measurement, bimanual examination, cervical cytology, and laboratory tests (glucose, lipids, liver enzymes, hemoglobin, thrombogenic mutations) are all classified as "not needed" for POP initiation 1
• A baseline weight and BMI measurement may be useful for monitoring over time 1
• Women with known medical problems may require additional evaluation 1

Advantages Over Combined Oral Contraceptives

• POPs do not contain estrogen, making them suitable for women with contraindications to estrogen including those with cardiovascular risk factors, immediate postpartum period, and breastfeeding 2
• POPs avoid estrogen-related adverse effects such as headache and cardiovascular events 2
• The desogestrel-containing POP has demonstrated contraceptive effectiveness similar to combined oral contraceptives 2

Common Side Effects and Management

Bleeding Irregularities

• The most commonly reported complaint with POPs is irregular bleeding patterns 2
• Unscheduled bleeding and spotting are common, particularly during the first 3-6 months of use 1
• These bleeding irregularities are generally not harmful and usually improve with persistent use 1
• Counseling about expected variable bleeding patterns before initiation improves compliance and acceptance 2

Treatment of Breakthrough Bleeding

• Adding 5 mg norethisterone acetate significantly reduces bleeding frequency and quantity in women experiencing vaginal bleeding on POPs 3
• This intervention showed significant improvement at 2,4, and 6 weeks compared to continuing single-dose POP, doubling the POP dose, or switching formulations 3
• Approximately 40% of women taking POPs report vaginal bleeding/spotting, with 25% finding this a reason for cessation 3

Important Counseling Points

• POPs do not protect against sexually transmitted diseases; consistent and correct use of male latex condoms reduces STD risk including HIV 1
• POPs are reversible and can be used by women of all ages 1
• Emphasize the critical importance of taking pills at the same time each day due to the short duration of contraceptive effect 1
• Discuss expected bleeding patterns upfront to reduce discontinuation rates 2

Special Considerations

• In situations where uncertainty exists about pregnancy status, the benefits of starting POPs likely exceed any risk; starting POPs should be considered with follow-up pregnancy testing in 2-4 weeks 1
• Progestin-only formulations (pills, injections, IUDs, or implants) may worsen acne in contrast to combined hormonal contraceptives which have anti-androgenic properties 1