Emergency contraceptives

Summary

Emergency contraception prevents pregnancy after unprotected sex if used before implantation. Options include oral pills (levonorgestrel, ulipristal) and the copper IUD, the most effective method, which also provides long-term contraception. These methods delay ovulation, block fertilization, or prevent implantation and are for emergency use only.

Overview

Also known as post-coital contraception, refers to methods used after unprotected sexual intercourse to prevent pregnancy. These methods are effective at any time during the menstrual cycle if administered before implantation. They primarily act by inhibiting or delaying ovulation, impairing fertilization, or preventing implantation. Importantly, emergency contraception does not terminate an established pregnancy and is ineffective once implantation has occurred.

Note
These methods should not replace regular contraceptive use but serve as a backup in emergencies.	ملاحظة

Indications

• Unprotected sexual intercourse.

• Contraceptive failure (e.g., condom rupture, missed oral contraceptive pills, or dislodged intrauterine device).

• Sexual assault without contraception.

Methods

1. Oral Hormonal Methods

• Levonorgestrel (LNG):

• Given as a single 1.5 mg dose within 72 hours, or two doses of 0.75 mg taken 12 hours apart.

• Prevents approximately 89% of pregnancies.

• Efficacy decreases with time; thus, earlier administration is preferred.

• Advantages:

• • • Accessible and well-tolerated.

    • Effective if taken within 72 hours of unprotected intercourse (most effective within 24 hours).

• Ulipristal Acetate (UPA):

• A selective progesterone receptor modulator, administered as a single 30 mg dose.

• Effective up to 120 hours (5 days) post-intercourse and more effective than LNG, particularly when ovulation is imminent.
  

• Combined Oral Contraceptives (Yuzpe Regimen):

• 100 µg ethinylestradiol plus 0.50 mg LNG (usually 4 tablets), followed by a repeat dose after 12 hours.

• Prevents up to 89% of pregnancies but is associated with more nausea and vomiting than LNG or UPA.
  

• Other agents (less commonly used today):

• High-dose progestins (e.g., older formulations of norethindrone).

• Danazol (600 mg, repeated after 12 hours), though largely obsolete due to low efficacy and significant side effects.

 

2. Intrauterine Device (IUD)

• Copper IUD (Cu-IUD):
  
  

• The most effective method of emergency contraception.

• Can be inserted immediately or up to 5 days after unprotected intercourse.

• Mechanism of action: The device releases copper ions, which are spermicidal and embryotoxic, and induces a sterile inflammatory reaction within the endometrium that prevents implantation. 

• Advantages: provides ongoing long-term contraception if left in place.

• Contraindications: active pelvic infection, acute cervicitis, or unexplained vaginal bleeding.

• Potential complications: infection, uterine perforation, or irregular bleeding.

• Antibiotic prophylaxis is recommended when inserting an IUD in women at risk of sexually transmitted infections.

• Age and parity are not contraindications to IUD use; it can be safely used even in adolescents and nulliparous women.