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Contraception & Abortion — Key Points by Topic

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1. Introduction / Global Context

• Over 200 million women worldwide want to avoid pregnancy but aren't using effective contraception.
• ~25 million unsafe abortions/year → 31,000 deaths + 7 million injuries annually — all preventable.

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2. Mechanism of Action

• Preventing ovulation → CHC (pill/patch/ring), POP with desogestrel/drospirenone, injectable, implant
• Thickening cervical mucus → all progestogen-only methods
• Preventing implantation → Cu-IUD, LNG-IUD
• Blocking sperm passage → diaphragm, cap
• Killing/blocking sperm entry → condoms, spermicides

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3. Efficacy & Effectiveness

• LARC methods (implant, IUDs): typical use ≈ perfect use failure rate (0.1–0.8%)
• Short-acting methods (pill, condom): typical use failure rates are much higher than perfect use
• Typical use pregnancy rates at 1 year:
  • No method: 85%
  • Condom: 13%
  • Pill/patch/ring: 7%
  • Injectable: 4%
  • Cu-IUD: 0.8% | LNG-IUD/Implant: 0.1%

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4. Safety — WHO Medical Eligibility Criteria (MEC)

• Category 4 = absolute contraindication to CHC:
  • Age >35 + smoking, BP >160/100, DVT (current/past), MI/stroke, known thrombogenic mutations, current breast cancer
• MEC has 4 levels (1 = no restriction → 4 = unacceptable risk)

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5. Drug Interactions with Hormonal Contraception

• Enzyme inducers reduce efficacy of pill, patch, ring, implant, POP:
  • Anticonvulsants: carbamazepine, phenytoin, phenobarbital, topiramate
  • Antibiotics: rifampicin (the main one)
  • Antiretrovirals: protease inhibitors, NNRTIs (efavirenz, nevirapine)
  • Antifungal: griseofulvin
• Solutions: switch to injectable, Cu-IUD or LNG-IUD (unaffected), or add condoms
• Broad-spectrum antibiotics do NOT reduce pill efficacy

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6. Side Effects of Hormonal Methods

• Common: unexpected bleeding, weight gain, headaches, mood swings, low libido
• Weight gain evidence: Only the injectable in adolescents has good evidence; no evidence for other hormonal methods
• Mood/libido: No good evidence of adverse effects
• Unexpected bleeding on COCP: common in first 3 months — investigate if persists >3 months

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7. Non-Contraceptive Benefits

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8. Combined Hormonal Contraception (CHC)

• Contains oestrogen + progestogen → pill, patch, ring; all similarly effective
• Mechanism: inhibit ovulation via FSH/LH suppression
• Second-generation progestogens (levonorgestrel, norethisterone) = first choice — lower VTE risk than 3rd/4th generation
• Pill: usually 21 days + 7-day break; can be taken continuously (no medical need for withdrawal bleed)
• VTE risk: 10/10,000 in COCP users vs 5/10,000 non-users vs 29–400/10,000 in pregnancy
• Absolute contraindications: migraine with aura, smokers >35 years, personal/family DVT/PE history

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9. Cancer Risk with COCP

• Reduced: ovarian (↓46% ever use, ↓50% with 10 years use), endometrial (~50%), colorectal
• Increased: breast cancer during use — risk returns to baseline 10 years after stopping
• Protection against ovarian/endometrial cancer persists >15 years after stopping
• Cervical cancer risk slightly increased (likely confounded by less condom use)

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10. Missed Pills

• 1 missed pill (24–48h late): take it ASAP, no extra precautions needed (usually)
• 2+ missed pills (>48h late): take most recent ASAP + condoms for next 7 days
• If missed in week 1 + unprotected sex in pill-free interval → EC required
• If missed in week 3 → skip pill-free interval, start new pack immediately

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11. Progestogen-Only Pill (POP)

• Desogestrel-containing POP: inhibits ovulation in 99% of cycles
• Other POPs: inhibit ovulation in <50% of cycles (rely on mucus effect)
• New drospirenone POP: 24 days + 4-day break
• Missed POP: use extra precautions (condoms) for 48 hours; EC if unprotected sex occurred

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12. Progestogen-Only Implant (Nexplanon®)

• Single rod (40×2 mm), etonorgestrel 68 mg, lasts 3 years
• Inserted subdermally 8 cm above medial epicondyle, non-dominant arm
• Contains barium (visible on X-ray); also locatable with low-frequency ultrasound
• Fertility restored within 1 week of removal
• No routine follow-up needed until replacement

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13. Progestogen-Only Injectable (Depo-Provera / Sayana Press)

• IM (150 mg) or SC (104 mg) every 13 weeks; both equally effective
• Amenorrhoea in >50% at 1 year
• Only hormonal method that delays return of fertility — up to 1 year after last injection
• Small risk of bone mineral density loss (~5% at lumbar spine) — plateaus, not associated with fractures, reversible on stopping
• No increased HIV acquisition risk vs implant/IUD

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14. LNG-IUD (Mirena®, Kyleena®, Jaydess®)

• 52 mg (Mirena) → licensed 6 years; if inserted ≥45 years → can stay until menopause/age 55
• 19.5 mg (Kyleena) → 5 years; 13.5 mg (Jaydess) → 3 years
• Does not prevent ovulation → works via endometrial atrophy + cervical mucus thickening
• Key benefit: reduces heavy menstrual bleeding by 90% at 12 months
• Initial unpredictable bleeding is common — counsel in advance to prevent unnecessary removal

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15. Copper IUD (Cu-IUD)

• Duration: 3–10 years depending on device; if inserted ≥40 → can stay until menopause
• Mechanism: inflammatory reaction toxic to sperm + inhibits implantation
• May cause heavier, more painful periods (treat with NSAIDs or tranexamic acid)
• Most effective emergency contraception (failure rate 1/1,000)

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16. IUD Complications

• If pregnancy occurs with IUD in situ: ~50% risk of ectopic — always scan first
• Evidence confirms IUDs do not delay return of fertility or cause infertility

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17. Barrier Methods

• Male condom: only reversible male method; protects against STIs including HIV; typical failure rate 13%
• Female condom: also protects against STIs; polyurethane
• Diaphragm/cap: typical failure rate ~18%; may increase UTIs
• Spermicides alone: not recommended (low effectiveness); Nonoxynol-9 may increase HIV transmission with frequent use

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18. Female Sterilization

• Laparoscopic: usually Filshie clips on fallopian tubes
• Failure rate: 1 in 200 (similar to LARC)
• Risk of ectopic if failure
• Effective contraception required until next menses after procedure
• Caesarean section sterilization: consent must be obtained well in advance
• Risk factors for regret: age <30, nulliparity, recent pregnancy, relationship issues

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19. Vasectomy

• Interruption of vas deferens; no-scalpel technique under local anaesthesia
• Failure rate: 1 in 2,000 (safer and more effective than female sterilization)
• Post-vasectomy semen analysis at 12 weeks → confirm azoospermia before stopping other contraception

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20. Fertility Awareness-Based Methods

• Calendar/rhythm: fertile window = shortest cycle − 20 to longest cycle − 10 (for 28-day cycle: days 8–18 abstinence)
• Temperature method: basal body temperature rises 0.5°C after ovulation (progesterone)
• Cervical mucus: fertile = clear, watery, slippery (like raw egg white); post-ovulation = thick, opaque
• Lactational amenorrhoea: ~2% pregnancy risk if <6 months post-partum, amenorrhoeic, fully breastfeeding
• All methods: high typical failure rates; require regular cycles and motivation

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21. Emergency Contraception (EC)

• Cu-IUD = most effective EC (failure 1/1,000); can be inserted up to 5 days after ovulation; provides ongoing contraception
• Ulipristal acetate (UPA 30 mg): more effective than LNG; use up to 120 hours after sex
• Levonorgestrel (LNG 1.5 mg): up to 72 hours after sex
• Both oral methods work by delaying ovulation (not abortifacient)
• Oral EC prevents only ~2/3 of expected pregnancies — much less effective than regular contraception
• Start ongoing contraception immediately after EC

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22. Abortion — Law (UK)

• 1967 Abortion Act (England, Scotland, Wales): requires 2 doctors to agree
• >95% performed under Ground C (<24 weeks, risk to physical/mental health of woman)
• Upper limit: 24 weeks (reflects fetal viability)
• ~1% for severe fetal abnormality (Ground E) — no gestational limit
• Northern Ireland: decriminalized in 2019 but services remain limited

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23. Methods of Abortion

• Medical abortion (most common where available):
  • Mifepristone (oral) then misoprostol 24–48 hours later
  • Up to 12 weeks: can be done and managed at home

  • 12 weeks: clinical facility required (larger fetus, more discomfort)

  • After 21 weeks + 6 days: feticide required (KCl intracardiac or digoxin) before expulsion
• Surgical abortion:
  • Up to 14 weeks: vacuum aspiration (<10 mins); local anaesthesia preferred
  • After 14 weeks: D&E (dilatation and evacuation)
  • Sharp curettage must never be performed (risk of perforation + intrauterine adhesions)
  • Cervical priming: 400 µg misoprostol sublingual 1 hour before, or mifepristone 24h before
  • Prophylactic antibiotics required for surgical (not medical) abortion

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24. Medical Abortion — What to Expect

• Incomplete abortion requiring surgery: <5%
• Ongoing pregnancy: 1–2%
• Severe infection: <1%
• Haemorrhage >1L: 0.1%
• Median bleeding: 12 days (at 8 weeks)
• Greater pain: with advanced gestation, nulliparity, dysmenorrhoea

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25. Sequelae of Abortion

• No association with breast cancer
• No adverse effect on mental health overall — but higher risk of distress in: pre-existing mental health issues, unsupported women, ambivalent women, those with moral objections
• Modern methods not associated with increased preterm delivery risk (recent studies)
• No impact on future fertility (absent serious complication)

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26. Post-Abortion Contraception

• Most women ovulate within first month after abortion; >50% resume sex within 2 weeks
• Start contraception immediately after abortion
• All hormonal methods can start at time of mifepristone
• IUD can be inserted at time of surgical abortion or after medical abortion expulsion
• Women using LARC post-abortion have significantly lower risk of subsequent unintended pregnancy

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27. Opportunities to Provide Contraception

• After EC: 2–3× higher risk of unintended pregnancy if further unprotected sex occurs in same cycle
• Post-partum: non-breastfeeding women may ovulate as early as day 21
• Antenatal/post-partum: 95% of post-partum women want to avoid pregnancy in next 12 months
• Post-miscarriage/ectopic: not all were unintended, but contraception should be discussed
• After ectopic treated with methotrexate: effective contraception essential (teratogenic)