Contraception
Contraception is the deliberate prevention of pregnancy through hormonal, intrauterine, barrier, or surgical methods, selected against a patient's medical eligibility and preferences. Long-acting reversible contraception, the etonogestrel implant and the intrauterine devices, is first-line for most patients because it removes the adherence step and carries failure rates under 1%.
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What this article covers
- Overview
Definition: contraception is the deliberate prevention of pregnancy using hormonal, intrauterine, barrier, behavioral, or surgical methods matched to a patient's medical eligibility and preferences.
- Epidemiology
Unintended pregnancy burden: about 45% of pregnancies in the United States are unintended, with a higher incidence among women of color and those of lower socioeconomic status.
- Risk factors
Adherence-dependent methods: the combined pill, patch, ring, progestin-only pill, and barrier methods require consistent correct use, so typical-use failure runs well above perfect-use failure.
- Pathophysiology
Combined hormonal contraception: estrogen plus progestin suppress hypothalamic gonadotropin-releasing hormone (GnRH) pulsatility, lowering follicle-stimulating hormone (FSH) and luteinizing hormone…
- Clinical features
Combined methods (pill, patch, ring): predictable, lighter menses and less acne, but breakthrough bleeding in 10% to 30% of users and rising VTE risk in smokers over 35; the patch delivers a higher average estrogen exposure than the pill.
- Differential diagnosis
Combined hormonal versus progestin-only: choose progestin-only when estrogen is contraindicated, migraine with aura, prior VTE, uncontrolled hypertension, or smoking over 15 cigarettes a day at 35 or…
- Diagnosis
What establishes eligibility: candidacy for a method is established by a directed history classified against the Centers for Disease Control and Prevention (CDC) Medical Eligibility Criteria (MEC)…
- Management
First action: confirm the patient's desire to prevent pregnancy, screen against the MEC, then offer LARC, the implant or an IUD, as first-line to any patient without a device-specific…
- Complications
CHC: a small VTE increase, higher in smokers 35 or older who smoke more than 15 cigarettes a day, and a stroke-risk contraindication in migraine with aura.
- Prognosis
Efficacy tiers: the implant, IUDs, and sterilization exceed 99% effectiveness; the pill, patch, ring, progestin-only pill, and DMPA are 90% to 99%; barrier methods are 75% to 90%; withdrawal alone is 68% to 74%.
- Prevention
Match risk to method at every visit: screen against the MEC, since a new comorbidity, migraine with aura or a VTE, should trigger reassessment of an existing CHC prescription.
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