Progestin-Only Pills (POPs) Have NO Role in Managing Unwanted Pregnancy
POPs are contraceptives designed to prevent pregnancy, not to manage or terminate an existing unwanted pregnancy. If a woman is already pregnant, POPs will not affect the pregnancy and should not be used 1.
Critical Distinction: Prevention vs. Management
POPs Are for Pregnancy Prevention Only
- POPs work by thickening cervical mucus and inconsistently inhibiting ovulation in only about half of cycles 1, 2
- They must be taken daily at the same time (within 3 hours) to maintain contraceptive effectiveness 1
- With typical use, approximately 9 out of 100 women become pregnant in the first year, making them less effective than other contraceptive methods 2
If Pregnancy Has Already Occurred
- A baseline urine pregnancy test should be performed before initiating any contraceptive method, including POPs 1
- If the test is positive, POPs are inappropriate and ineffective 1
- The patient needs pregnancy options counseling, not contraception 1
What You May Be Confusing: Emergency Contraception
Emergency Contraception Is Different from Regular POPs
If the question concerns preventing pregnancy after unprotected intercourse (not managing an established pregnancy), emergency contraception with levonorgestrel is the appropriate intervention:
- Levonorgestrel emergency contraception (1.5 mg single dose or 0.75 mg twice, 12 hours apart) should be offered to females who have been vaginally penetrated or who think ejaculate contacted their genitalia 1
- This must be taken within 72 hours of unprotected intercourse for FDA-approved use, though efficacy decreases with time 3, 4
- Taking both 0.75 mg tablets at once is easier and equally effective without increasing adverse effects 1, 3
- Emergency contraception prevents approximately 80% of pregnancies when taken promptly 5
Mechanism Clarification
- Emergency contraception works primarily by blocking or delaying ovulation when given before the preovulatory LH peak 5
- It may also affect sperm migration, but there is no evidence for an anti-implantation effect 5
- Once pregnancy is established, emergency contraception will not work 5
Appropriate Use of Regular POPs
When POPs Are Indicated
- Breastfeeding women, as POPs do not affect milk production 2
- Women with contraindications to estrogen (history of venous thromboembolism, hypertension, migraine with aura) 2, 6
- Women who need ongoing contraception and can adhere to strict daily timing requirements 1
When POPs Are NOT Recommended
- POPs are generally not recommended as first-choice contraceptives for healthy adolescents due to strict timing requirements, lower effectiveness, and irregular bleeding patterns 2
- Women who frequently miss pills should consider more effective, user-independent methods like IUDs or implants 1
Common Pitfall to Avoid
Do not confuse emergency contraception (levonorgestrel for post-coital prevention) with regular POPs (daily contraception) or with management of established pregnancy. These are three entirely different clinical scenarios requiring different interventions 1, 5, 7.