What birth control options are recommended for a patient with protein S deficiency?

Birth Control Recommendations for Protein S Deficiency

Women with protein S deficiency should use progestin-only intrauterine devices (IUDs) or copper IUDs as first-line contraception, and must strictly avoid all combined estrogen-progestin contraceptives due to significantly elevated thrombotic risk. 1

Primary Recommended Options

Levonorgestrel IUD (Preferred)

• Provides the highest efficacy (<1% pregnancy rate annually) with no increased thrombotic risk in women with thrombophilia 1
• Reduces menstrual bleeding, which is particularly beneficial if anticoagulation therapy is needed 2
• Does not require daily adherence, eliminating user-dependent failure 1
• Safe regardless of disease activity or other thrombotic risk factors 2

Copper IUD (Equally Safe Alternative)

• Completely hormone-free option with equivalent contraceptive efficacy (<1% failure rate) 1
• No hormonal effects on coagulation pathways 1
• May increase menstrual bleeding, which could be problematic if anticoagulation is required 1

Progestin-Only Pills (Less Preferred)

• Safe thrombotic profile in women with thrombophilia 1
• Lower efficacy (5-8% failure rate) due to strict adherence requirements—must be taken at the same time daily 1
• No increased venous thromboembolism risk (relative risk 0.90) 1

Absolutely Contraindicated Options

Combined Estrogen-Progestin Contraceptives (All Forms)

• Protein S deficiency represents a severe thrombophilia that creates unacceptable thrombotic risk when combined with estrogen 3, 4
• Women with protein S deficiency taking oral contraceptives have a 7-fold increased risk of venous thromboembolism compared to non-users 3
• Absolute VTE risk reaches 4.3-4.6 per 100 pill-years in women with severe thrombophilia (including protein S deficiency) using combined contraceptives 3
• Estrogen-containing contraceptives further decrease free protein S levels, compounding the existing deficiency 5, 6, 7
• This prohibition includes all delivery methods: oral pills, transdermal patches, and vaginal rings 1, 8

Depot Medroxyprogesterone Acetate (DMPA)

• Should be avoided due to higher VTE risk (relative risk 2.67) compared to other progestin-only methods 1
• Thrombotic risk approaches that of combined oral contraceptives 1
• Additional concern for bone mineral density loss with long-term use 1

Clinical Implementation Algorithm

Step 1: Confirm Diagnosis

• Document protein S deficiency with laboratory testing before contraceptive counseling 3, 4
• Assess for additional thrombotic risk factors (family history of VTE, personal history of thrombosis) 3

Step 2: First-Line Recommendation

• Offer levonorgestrel IUD as optimal choice 1, 2
• Explain <1% pregnancy rate and lack of thrombotic risk 1
• Emphasize benefit of reduced menstrual bleeding if anticoagulation is present 2

Step 3: Alternative if IUD Declined

• Copper IUD if patient prefers hormone-free option 1
• Progestin-only pills if patient cannot tolerate IUD, with strong counseling about daily adherence requirements 1

Step 4: Barrier Methods as Adjunct

• Recommend condoms for sexually transmitted infection protection regardless of primary method chosen 1

Critical Pitfalls to Avoid

• Never prescribe combined hormonal contraceptives to women with protein S deficiency, even if they request it—the thrombotic risk is unacceptable 3, 4
• Do not assume progestin implants are equivalent to other progestin-only methods—insufficient data exists for women with severe thrombophilia 1
• Avoid DMPA despite being progestin-only due to its unique thrombogenic profile 1
• Do not delay contraceptive counseling until after a thrombotic event occurs 3, 4

Emergency Contraception

• Levonorgestrel emergency contraception (Plan B) is safe and not contraindicated in protein S deficiency 1
• No medical contraindications exist for progestin-only emergency contraception 1
• Risks of emergency contraception are substantially lower than risks of unintended pregnancy 1

Special Considerations

If Anticoagulation Required

• Levonorgestrel IUD becomes even more advantageous due to menstrual bleeding reduction 2
• Copper IUD may worsen bleeding in anticoagulated patients 1

If Pregnancy Desired in Future

• IUDs are immediately reversible with rapid return to fertility upon removal 1
• No delay in fertility restoration compared to barrier methods 1