Contraception - A Comprehensive Overview

Effectiveness at a Glance

• Ganong's Review of Medical Physiology, 26e (failure rates per 100 woman-years also confirm vasectomy 0.02, tubal ligation 0.13, combined OCP 0.27-0.32, IUD 1.3-1.5, diaphragm 1.9, condom 3.6, rhythm 15.5)

1. Combined Hormonal Contraceptives (CHCs)

Mechanism of Action

• Suppress gonadotropins (both FSH and LH): estrogen suppresses FSH; progestin blunts the LH surge, preventing ovulation
• Thicken cervical mucus (progestin): impedes sperm penetration
• Alter endometrium: renders it inhospitable for implantation
• Low-dose estrogen preparations are as effective as high-dose ones

Forms

• Taken for 21 active days, then 5-7 days off for withdrawal bleeding (or 24/4 in newer formulations)
• Contain ethinyl estradiol + a synthetic progestin (norethindrone, levonorgestrel, desogestrel, norgestimate, drospirenone)
• Progestin generations matter:
  • 1st-3rd generation (norethindrone, LNG, norgestimate): 3× risk of VTE over non-users
  • 4th generation - drospirenone (Yaz, Yasmin): derived from 17α-spironolactone, has doubled VTE risk compared to LNG-containing pills, 6× over non-users - use has declined sharply due to over $1.6 billion in lawsuits

• Contains ethinyl estradiol + norelgestromin or levonorgestrel
• Applied weekly for 3 consecutive weeks, then patch-free week for withdrawal bleed
• Less effective in women >90 kg; total estrogen exposure may be higher than oral pills, increasing VTE risk
• Contraindicated in BMI ≥30 kg/m²

• Contains ethinyl estradiol + etonogestrel
• Inserted vaginally, left in place for 3 weeks, removed for 1 week
• Most common reason for discontinuation: vaginal irritation or ring expulsion

2. Progestin-Only Contraceptives

a) Progestin-Only Pills ("Mini-pill")

• Usually contain norethindrone (low daily dose)
• Must be taken at same time each day - less margin for error
• Irregular menstrual cycles are more common
• Alternative: drospirenone 4 mg - 24 active + 4 placebo days per cycle

b) Injectable - DMPA (Depo-Provera)

• Medroxyprogesterone acetate (MPA) 150 mg IM or 104 mg SC every 3 months
• Provides high, sustained progestin levels; amenorrhea common
• Return to fertility may be delayed 6-12+ months after stopping
• Bone loss with long-term use - limit to 2 years unless no other option is appropriate
• Common side effect: weight gain

c) Progestin Implant (Nexplanon)

• Etonogestrel rod implanted subdermally in upper arm
• Effective for up to 3 years; as reliable as sterilization
• Fully reversible upon removal
• LARC (Long-Acting Reversible Contraceptive)

d) Levonorgestrel IUD

• Several options: 3, 5, or 7 years of contraception
• Also highly effective treatment for heavy menstrual bleeding
• Avoid in: active pelvic inflammatory disease, history of ectopic pregnancy
• LARC - most effective reversible methods

3. Non-Hormonal IUD - Copper-T

• Provides contraception for up to 10 years
• Mechanism: copper exerts a spermatocidal effect; also prevents sperm from fertilizing ova
• Does not suppress ovulation - suitable for women who prefer hormone-free contraception
• Important downside: increases menstrual bleeding (contrast to LNG-IUD which reduces it)
• IUDs in general may cause intrauterine infections, usually within first month of insertion and mainly in women with STI exposure

4. Barrier Methods

5. Fertility Awareness Methods (FAMs)

• Track menstrual cycles, basal body temperature, cervical mucus (Billings method), or combinations
• Typical use failure: ~24% - higher than most other methods
• Lactational Amenorrhea Method (LAM): effective only if exclusively breastfeeding, <6 months postpartum, and no return of menses

6. Permanent Sterilization

• For vasectomy: use backup contraception for first 3 months until azoospermia confirmed

7. Emergency Contraception (EC)

• The copper IUD is the most effective form of emergency contraception - preferred when rapid, reliable EC is needed with ongoing protection
• Levonorgestrel EC is generally better tolerated than estrogen-progestin combination regimens

8. Choosing a Contraceptive Method - Key Questions

1. Does the patient want hormonal contraception? If no → copper IUD, condom, diaphragm, fertility awareness
2. Are there contraindications to estrogen? (VTE history, migraine with aura, age >35 + smoking, cardiovascular disease) → progestin-only methods
3. What comorbidities exist? Consult the CDC US Medical Eligibility Criteria (USMEC) for guidance
4. Desired duration? Short-term → pills/patch/ring; Long-term → LARC (implant, IUD)
5. Breastfeeding? → progestin-only (estrogen inhibits milk production)
6. STI risk? → always add condoms regardless of primary method

Key Contraindications to Combined OCPs (estrogen-containing)

• Active or history of thromboembolic disease (DVT/PE)
• Stroke or ischemic heart disease
• Migraine with aura
• Uncontrolled hypertension
• Breast cancer (current)
• Age >35 + cigarette smoking (carries higher death risk - only age group where OCPs increase mortality risk)
• Liver disease / hepatic tumors

Special Considerations

• Adolescents: Low-dose progestin IUDs are recommended for early adolescence to improve compliance. Estrogen and progestin dosing often needs adjustment from adolescent to perimenopausal years.
• Postmolar pregnancy: Oral contraceptives can be used safely after molar evacuation; IUDs should be deferred until hCG normalizes to avoid perforation risk.
• Drug interactions: Antiretrovirals significantly alter hormonal contraceptive efficacy - a 2024 systematic review (PMID 38762199) confirmed important interactions requiring method adjustment.
• Adolescents (2025 AAP guideline, PMID 40518137): The American Academy of Pediatrics reaffirmed broad access to all contraceptive methods for adolescents including LARCs as first-line options.

Sources

• Textbook of Family Medicine, 9e (Harper, Wilfing, Blanner - Chapter 26)
• Lippincott Illustrated Reviews: Pharmacology (Chapter 25)
• Ganong's Review of Medical Physiology, 26e (Chapter 22)
• U.S. Selected Practice Recommendations for Contraceptive Use, 2024 - CDC (PMID 39106301)

Contraception After Molar Pregnancy

Why Contraception Matters Post-Molar

• Cause hCG to rise, making it impossible to distinguish a new pregnancy from developing GTN
• Require interruption of the surveillance protocol
• Complicate or delay initiation of chemotherapy if GTN is confirmed

Duration of Contraception Required

• Average time to first normal hCG after evacuation: ~9 weeks
• After achieving non-detectable hCG, risk of GTN approaches zero

Which Methods Are Safe?

✅ Oral Contraceptive Pills (OCPs) - SAFE

"Data from a prospective trial and other centers indicate that oral contraceptive use does not increase the risk of postmolar trophoblastic disease. It appears that oral contraceptives may be used safely after molar evacuation during the entire interval of hormonal follow-up." - Berek & Novak's Gynecology

• The early reports of increased persistent tumor in OCP users were not confirmed in prospective studies
• Combined OCPs and progestin-only pills are both acceptable options
• A key additional benefit: hormonal contraception keeps hCG interpretable because OCPs prevent ovulation and thus prevent a new intrinsic rise in hCG

✅ Barrier Methods - SAFE

• Male condom, female condom, diaphragm - all acceptable
• Condoms have the added benefit of STI protection

❌ Intrauterine Devices (IUDs) - DEFERRED Until hCG Normalizes

"Because of the potential risk of uterine perforation, bleeding, and infection, intrauterine devices should not be inserted until the patient achieves a normal hCG level." - Berek & Novak's Gynecology

⚠️ Sterilization - Special Consideration

• Hysterectomy does not eliminate the need for hCG follow-up - it does not prevent metastasis
• If the patient is unsure or desires future fertility, sterilization should be deferred

After GTN Treatment

• 12 months of surveillance with contraception is recommended following treatment to allow complete surveillance for relapse (Schwartz's Principles of Surgery)
• Any increase in β-hCG during surveillance triggers further evaluation and consideration of further chemotherapy

Summary Table

• Berek & Novak's Gynecology, Chapter 41 (Gestational Trophoblastic Disease)
• Schwartz's Principles of Surgery, 11e
• Braga A, Berkowitz R, Horowitz N. Etiology, Natural History, and Management of Recent Advances in Molar Pregnancy. Obstet Gynecol. 2025. (PMID 40638920)
• Cooper M, Cameron S. Contraception after abortion, miscarriage, ectopic and molar pregnancy. Best Pract Res Clin Obstet Gynaecol. 2024. (PMID 38142524)