Reproductive · Contraception
The facts most likely to be tested
The copper intrauterine device (Cu-IUD) is the most effective form of emergency contraception and can be inserted up to 5 days after unprotected intercourse.
Ulipristal acetate is a selective progesterone receptor modulator (SPRM) that remains effective for up to 120 hours (5 days) post-coitus.
Levonorgestrel (Plan B) is most effective when taken within 72 hours of unprotected intercourse and has decreased efficacy in patients with a high BMI (>25-30 kg/m²).
Emergency contraception functions primarily by delaying or inhibiting ovulation rather than preventing implantation of a fertilized egg.
Ulipristal acetate is superior to levonorgestrel in efficacy, particularly as the time interval from intercourse increases toward the 5-day limit.
A negative pregnancy test is not required prior to the administration of emergency contraception, as these agents do not disrupt an established pregnancy.
The copper IUD provides the added benefit of serving as a highly effective form of long-term contraception after the emergency window has passed.
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A 22-year-old female presents to the clinic 4 days after having unprotected intercourse. She has a history of obesity with a BMI of 34 kg/m². She is concerned about the risk of pregnancy and requests the most effective method of emergency contraception available. Her physical examination is unremarkable, and a urine pregnancy test is negative.
What is the most appropriate next step in management?
Insertion of a copper intrauterine device (Cu-IUD)
The copper IUD is the most effective form of emergency contraception and is not affected by the patient's high BMI, unlike levonorgestrel, which has reduced efficacy in patients with elevated BMI.
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High yield triage
Etiology / Epidemiology
Indicated for unprotected intercourse or contraceptive failure. Efficacy is time-dependent; initiate as soon as possible.
Clinical Manifestations
No physical exam findings; diagnosis is based on patient history of recent sexual activity and negative pregnancy test.
Diagnosis
Confirm non-pregnant status via urine beta-hCG prior to administration. Pregnancy of unknown location must be excluded if symptoms exist.
Treatment
Levonorgestrel (Plan B) is first-line within 72 hours; Ulipristal is superior up to 120 hours. Copper IUD is most effective.
Prognosis
Does not cause abortion of an established pregnancy. Ectopic pregnancy risk remains if treatment fails.
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Epidemiology & Etiology
Indicated for patients seeking to prevent pregnancy after unprotected intercourse, sexual assault, or barrier method failure. Efficacy decreases as the interval from coitus increases. It is not an abortifacient and will not disrupt an established pregnancy.
Pertinent Anatomy
The hypothalamic-pituitary-ovarian axis is the target of hormonal agents. The endometrium is the target of the copper IUD, which induces a sterile inflammatory response.
Pathophysiology
Levonorgestrel acts primarily by delaying or inhibiting ovulation. Ulipristal is a selective progesterone receptor modulator that delays follicular rupture. The Copper IUD creates a spermicidal environment and prevents fertilization.
Clinical Manifestations
Patients are typically asymptomatic. Red flags include lower abdominal pain or vaginal bleeding, which may indicate an existing ectopic pregnancy or spontaneous abortion. A negative pregnancy test is mandatory before initiation.
Diagnosis
The urine beta-hCG is the gold standard to rule out existing pregnancy. If the patient is already pregnant, emergency contraception is ineffective and unnecessary. No other diagnostic testing is required.
Treatment
Levonorgestrel (1.5 mg) is the standard oral agent within 72 hours. Ulipristal (30 mg) is more effective for patients with BMI >25 or those presenting between 72-120 hours. The Copper IUD is the most effective method regardless of BMI. Contraindications for Ulipristal include breastfeeding and known pregnancy.
Prognosis
Failure rates are low but non-zero. Patients must be counseled that if menses does not occur within 3 weeks, a follow-up pregnancy test is required. Ectopic pregnancy must be ruled out if the patient presents with pelvic pain after treatment failure.
Differential Diagnosis
Established pregnancy: positive beta-hCG
Ectopic pregnancy: adnexal mass or pain
Spontaneous abortion: vaginal bleeding and cramping
Pelvic inflammatory disease: cervical motion tenderness
Ovarian cyst rupture: sudden onset unilateral pain