In the late 1990s, the World Health Organization (WHO) created the Medical Eligibility Criteria for Contraceptive Use (MEC), which provide evidence-based recommendations for safe and effective contraception in women with medical problems. The WHO MEC incorporate the best available evidence, are periodically updated, and are designed to be modified for specific populations. The US Centers for Disease Control and Prevention published US MEC in 2010. Changes to WHO guidelines for use in the US population include the following areas: breastfeeding, intrauterine device use, valvular heart disease, ovarian cancer, uterine fibroids, and venous thromboembolism. Medical conditions not covered by WHO recommendations but added to the US MEC include contraceptive guidance for women with inflammatory bowel disease, history of bariatric surgery, rheumatoid arthritis, endometrial hyperplasia, history of peripartum cardiomyopathy, and history of solid organ transplant. This article reviews the changes and additions to WHO MEC found in the US MEC.