Emergency contraception

Progestin (levonorgestrel)-Only Regimen

General
  • First dose within 48 hours after unprotected intercourse followed by second dose 12 hours later
    • May also be taken as single dose (double dose)
  • Relative risk reduction of pregnancy = 89% (1% with vs 8% without)
    • Effectiveness may be reduced in obese patients; some emerging evidence suggests doubling dose for obese patients[1]

Adverse Reactions
  • Nausea (23%)
  • Vomiting (6%)
  • No teratogenesis

Dosing
  • Plan B (marketed specifically for emergency contraception) - levonorgestrel 0.75mg PO per pill
  • May also be taken as one-time dose of levonorgestrel 1.5mg PO once

Yuzpe Regimen (Combination OCPs)

General
  • First dose within 72 hours after unprotected intercourse followed by second dose 12 hours later
  • May be given up to 120 hours later (but efficacy reduced)
  • Reduces risk of pregnancy by 75% (2% with vs 8% without)

Adverse Reactions
  • Nausea (50%)
  • Vomiting (20%)

Safety
  • No teratogenic effect

Contraindications
  • Pregnancy

FDA approved regimens
  • Ovral, Ogestrel - 2 pills (100 ug ethiny estradiol/0.5mg levonorgestrel) per dose; repeat in 12h
  • Alesse, Aviane, Levlite - 5 pills (100 ug ethiny estradiol/0.5mg levonorgestrel) per dose; repeat in 12h
  • Levlen, Levora, Lo/Ovral, Low-Ogestrel - 4 pills (120 ug ethiny estradiol/0.6mg levonorgestrel) per dose; repeat in 12h
  • Triphasil, Tri-Levlen, Trivora - 4 pills (120 ug ethiny estradiol/0.5mg levonorgestrel) per dose; repeat in 12h

Ulipristal acetate (Ella)
  • Progesterone-receptor modulator, effective up to 120 hours after unprotected sex
  • May be more effective than levonorgestrel in overweight patients[2]
  • 30 mg PO in single dose
  • Adverse effects: Nausea (~13%), abdominal pain (8-15%), headache (19%)[3]

IUD
  • Copper intrauterine device (Paragard) can be used as emergency contraception up to 120 hours after unprotected sex
  • Advantages:
    • More effective than oral regimens (>99% vs ~88%)[4]
    • Serves as long-acting reversible contraception for up to 12 years after insertion
  • Disadvantages:
    • Contraindicated in patients with PID or active gonorrhea/chlamydia: STD screening recommended prior to insertion
    • Not a very feasible method in the ED

See Also

References
  1. Edelman A, Cherala G, Blue S, Erikson D, Jensen J. Impact of obesity on the pharmacokinetics of levonorgestrel-based emergency contraception: single and double dosing. Contraception. 2016 ;94:52-57.
  2. Glasier A, Cameron ST, Blithe D, Scherrer B, Mathe H, Levy D, Gainer E, Ulmann A. Can we identify women at risk of pregnancy despite using emergency contraception? Data from randomized trials of ulipristal acetate and levonorgestrel. Contraception. 2011;84:363-7.
  3. Micromedex
  4. http://ec.princeton.edu/questions/ec-review.pdf#page=3
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