Emergency Contraception

• EC is indicated for individuals who have had unprotected intercourse or contraception failure and who do not wish to conceive. [16]

• Type of emergency contraceptives are based on the following:

  • Contraindications (e.g., cardiovascular disease, migraines, liver disease, obesity)

  • Wish for long-acting contraception

• EC should be initiated as soon as possible to maximize efficacy.

General

• Does not disrupt embryo implantation or already established pregnancies

• Indications

  • Individuals who meet standard criteria for an IUD

  • Individuals who desire long-acting contraception

  • Individuals who have a BMI ≥ 30

Types

• Copper intrauterine device

  • Most effective emergency contraception method

  • Mechanism of action: prevents fertilization by interfering with sperm and ovum viability and function [16][18]

  • For more information, see “Nonhormonal copper device.”

• Progestin intrauterine device: prevents fertilization by interfering with sperm and ovum function and transport [19]

Adverse effects

• Abnormal uterine bleeding and/or menstrual changes

• Dysmenorrhea

• Pelvic pain following insertion

General

• Most effective when taken within 3 days of unprotected intercourse (ulipristal acetate can be taken within 5 days)

• Does not disrupt embryo implantation or already established pregnancies

• Significantly less effective in obese (BMI ≥ 30 kg/m2) or overweight (BMI 25–29.9 kg/m2) individuals [20][21]

• For more information on the mechanisms of action, see “Pharmacodynamics” in "Hormonal contraceptives."

Types

• Antiprogestins (ulipristal acetate) [22]

  • Most effective oral emergency contraception method

  • Requires a prescription in the US

  • Administered as a single dose

• Progestins (levonorgestrel) [20]

  • Available as an over-the-counter medication in the US

  • Typically administered as a single dose or as two doses over one day

• Combined oral contraceptives pills (Yuzpe regimen)

  • Usually a combination of ethinyl estradiol and levonorgestrel

  • Inhibits the LH/FSH → prevents estrogen surge → inhibits LH surge → prevents ovulation

  • Requires a prescription in the US

  • Typically administered as a single dose or as two doses over one day

Adverse effects

• Headache, fatigue, dizziness

• Nausea, vomiting

• Breast tenderness, dysmenorrhea, menstrual changes (e.g., earlier onset of menstrual bleeding associated with levonorgestrel use, delayed onset of menstrual bleeding related to ulipristal acetate use)