Why prescribe a patient a progesterone-only pill (POP) instead of a combination oral contraceptive (COC) pill?

When to Prescribe Progestin-Only Pills Instead of Combined Oral Contraceptives

Progestin-only pills (POPs) should be prescribed instead of combined oral contraceptives (COCs) for patients with thrombosis risk factors, cardiovascular disease, antiphospholipid antibodies, breastfeeding women, and those who cannot tolerate estrogen-related side effects. 1

Medical Conditions Requiring Progestin-Only Pills

Thrombosis Risk Factors

• POPs are the preferred oral contraceptive for patients with:
  • Positive antiphospholipid antibodies (aPL) 2, 1
  • History of deep venous thrombosis (DVT) or pulmonary embolism (PE) 2
  • Known thrombophilia 2
  • Active cancer 2

The risk of venous thromboembolism (VTE) in healthy women taking COCs is 3-6 times higher than baseline, while POPs show no increased thrombosis risk (RR 0.90,95% CI 0.57-1.45) 1.

Cardiovascular Conditions

• POPs are indicated for patients with:
  • Hypertension 2
  • Peripartum cardiomyopathy 2
  • Valvular heart disease 2
  • Congenital heart disease 3

A study of patients with congenital heart disease found that many had inappropriately used estrogen-containing contraceptives despite contraindications, with 3.8% experiencing thromboembolic events during use 3.

Autoimmune Conditions

• For patients with systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS):
  • COCs should be discouraged in women with positive aPL 2
  • Progestin-only methods are suitable for these women, although their use should be weighed against the risk of thrombosis 2
  • The American College of Rheumatology recommends screening all patients for aPL before prescribing contraceptives 1

Breastfeeding Women

• POPs are safe for breastfeeding women, while COCs may affect milk production 2, 1
• Can be started after 1 month postpartum in breastfeeding women 1

Estrogen Intolerance

• For women experiencing estrogen-related adverse effects such as:
  • Headaches 4
  • Nausea
  • Breast tenderness
  • Fluid retention

Efficacy Comparison

• POPs with desogestrel have shown similar contraceptive effectiveness to COCs 4
• First-year failure rate for perfectly used POPs is 0.5% 5
• Typical failure rate is estimated to be closer to 5% due to late or omitted pills 5
• The POP containing desogestrel was not associated with a significantly lower risk of accidental pregnancy compared to levonorgestrel POP (rate ratio 0.27,95% CI 0.06 to 1.19) 6

Practical Considerations for POP Use

Timing Requirements

• POPs must be taken at the same time every day (within a 3-hour window) 1
• No pill-free interval 1
• Stricter timing requirements than COCs 1

Side Effect Profile

• Most common complaint with POPs is irregular bleeding patterns 5, 4
• POPs may cause more bleeding problems than COCs, though this difference is not always statistically significant 6
• POPs avoid estrogen-related side effects 4, 7

Patient Counseling

• Counseling about variable bleeding patterns may improve compliance and acceptance 4
• Irregular bleeding is often temporary, especially during the first few months of therapy 7
• Backup contraception should be used for 7 days when switching from a COC to a POP 1

Conclusion

When choosing between POPs and COCs, the primary consideration should be patient safety based on individual risk factors. POPs are the safer choice for women with thrombosis risk factors, cardiovascular conditions, positive antiphospholipid antibodies, during breastfeeding, and for those who cannot tolerate estrogen-related side effects. While POPs require stricter adherence to timing and may cause more irregular bleeding, they offer comparable contraceptive efficacy with fewer serious health risks for these populations.