What are the various contraceptive methods, how do combined estrogen‑progestin oral contraceptives differ from progestin‑only pills, and which patients should be prescribed combined pills versus progestin‑only pills?

Birth Control Options and Selection Guide

For most healthy women, combined estrogen-progestin pills are appropriate first-line contraception, but you must prescribe progestin-only pills for women with thrombotic risk factors (including antiphospholipid antibodies, history of VTE, active lupus, migraines with aura, uncontrolled hypertension ≥160/100, or smoking age ≥35), breastfeeding women in the first 6 weeks postpartum, and those with contraindications to estrogen. 1, 2

Available Contraceptive Methods

Hormonal Methods

Combined Hormonal Contraceptives (CHCs):

• Oral pills (COCs): contain estrogen (typically ethinyl estradiol ≤35 μg) plus progestin
• Transdermal patch: releases 150 μg norelgestromin + 20 μg ethinyl estradiol daily
• Vaginal ring: releases 120 μg etonogestrel + 15 μg ethinyl estradiol daily
• Typical use failure rate: 9 per 100 women-years 3

Progestin-Only Methods:

• Progestin-only pills (POPs): contain only progestin, no estrogen
• DMPA injections (depot medroxyprogesterone acetate)
• Subdermal implants (etonogestrel)
• Levonorgestrel IUD
• Typical use failure rate for POPs: 9 per 100 women-years 3

Long-Acting Reversible Contraceptives (LARCs):

• Copper IUD (non-hormonal)
• Levonorgestrel IUD
• Subdermal progestin implant
• These have the lowest failure rates 1

Non-Hormonal Methods

• Copper IUD
• Barrier methods (condoms, diaphragm, cervical cap)
• Fertility awareness-based methods
• Sterilization (male/female)

Key Differences: Combined vs. Progestin-Only Pills

Combined Estrogen-Progestin Pills

Mechanism:

• Estrogen provides synergistic ovulation inhibition with progestin
• Estrogen ensures better cycle control and reduces breakthrough bleeding
• Both components work together to suppress gonadotropins 4

Advantages:

• More predictable bleeding patterns
• Can be used continuously/extended cycle to reduce menstrual frequency
• Generally better cycle control than progestin-only options 5

Critical Risk:

• VTE risk increases 36-fold above baseline (from 1/10,000 to 36/10,000 women annually) 1
• VTE risk varies by progestin type: odds ratios range 2.2 to 6.6 1

Progestin-Only Pills

Mechanism:

• Ovulation inhibition through progestin alone (dose-dependent)
• Cervical mucus thickening to block sperm penetration
• Endometrial changes preventing implantation 6

Advantages:

• No increased VTE risk (RR 0.90,95% CI 0.57-1.45) 1
• Safe for women with thrombotic risk factors
• Can be used during breastfeeding
• No estrogen-related contraindications 1

Disadvantages:

• More irregular bleeding patterns (common and expected)
• Must be taken at same time daily (less forgiving than COCs)
• Requires consistent counseling about bleeding irregularities 3

Clinical Decision Algorithm: Who Gets What

PRESCRIBE COMBINED PILLS (COCs) FOR:

✓ Healthy women without contraindications ✓ Age <35 if non-smoker (smoking not contraindicated in women <35) 7 ✓ Stable, low-activity SLE patients who are aPL-negative 1 ✓ Women desiring predictable bleeding patterns ✓ Blood pressure <160/100 mmHg 7

Start with: 30-35 μg ethinyl estradiol + levonorgestrel or norgestimate 7

PRESCRIBE PROGESTIN-ONLY PILLS (POPs) FOR:

✓ Antiphospholipid antibody-positive patients (with or without clinical APS) - STRONGLY RECOMMENDED 1, 8 ✓ History of VTE or current thrombophilia ✓ Active or moderate-to-severe SLE (including nephritis) 1 ✓ Migraines with aura or focal neurologic symptoms 7 ✓ Severe uncontrolled hypertension (≥160/100 mmHg) 7 ✓ Breastfeeding women (especially first 6 weeks postpartum) 3 ✓ Smokers age ≥35 years ✓ Complicated valvular heart disease ✓ Peripartum cardiomyopathy with any impairment 2 ✓ History of thrombogenic conditions ✓ Women who cannot tolerate estrogen side effects

AVOID SPECIFIC FORMULATIONS:

Do NOT use transdermal estrogen-progestin patch in SLE patients - higher estrogen exposure than oral/vaginal routes increases flare/thrombosis risk 1

Do NOT use DMPA in aPL-positive patients - concern for thrombogenicity (RR 2.67 for VTE, similar to COCs) 1

Critical Counseling Points

For Combined Pills:

• Start within first 5 days of menses for immediate protection; if started later, use backup contraception for 7 days 3
• Expect irregular bleeding first 3-6 months (generally not harmful) 3
• If vomiting/diarrhea ≥48 hours: use backup contraception until 7 consecutive pills taken after symptoms resolve 3

For Progestin-Only Pills:

• Must take at same time daily - less margin for error than COCs
• Irregular bleeding is expected and normal - counsel extensively before initiation 3
• Amenorrhea common after prolonged use (not harmful, provide reassurance) 3
• Use backup contraception for 7 days if starting >5 days after menses 3

Common Pitfalls to Avoid

1. Failing to screen for aPL before prescribing COCs - presence of aPL is an absolute contraindication to estrogen-containing contraceptives 1, 8

2. Prescribing COCs to active/moderate SLE patients - only studied in stable, low-activity disease 1

3. Inadequate counseling about bleeding irregularities - leading cause of discontinuation; enhanced counseling reduces discontinuation rates 3

4. Assuming all progestin-only methods have same thrombotic risk - DMPA has higher VTE risk than POPs or levonorgestrel IUD 1

5. Restricting contraceptive options unnecessarily - remember pregnancy-related VTE risk (>10 times higher than COC use) and pregnancy complications in high-risk patients far exceed contraceptive risks 1

Emergency Contraception Note

Levonorgestrel emergency contraception has NO medical contraindications - including thrombophilia, SLE, and aPL-positive status. Discuss with ALL patients as risks are low compared to unplanned pregnancy 1