© 2014 by The American College of Obstetricians and Gynecologists. OBJECTIVE: To conduct a retrospective observational cohort study to estimate the abortion complication rate, including those diagnosed or treated at emergency departments (EDs). METHODS: Using 2009-2010 abortion data among women covered by the fee-for-service California Medicaid program and all subsequent health care for 6 weeks after having an abortion, we analyzed reasons for ED visits and estimated the abortion-related complication rate and the adjusted relative risk. Complications were defined as receiving an abortion-related diagnosis or treatment at any source of care within 6 weeks after an abortion. Major complications were defined as requiring hospital admission, surgery, or blood transfusion. RESULTS: A total of 54,911 abortions among 50,273 feefor- service Medi-Cal beneficiaries were identified. Among all abortions, 1 of 16 (6.4%, n53,531) was followed by an ED visit within 6 weeks but only 1 of 115 (0.87%, n5478) resulted in an ED visit for an abortionrelated complication. Approximately 1 of 5,491 (0.03%, n515) involved ambulance transfers to EDs on the day of the abortion. The major complication rate was 0.23% (n5126, 1/436): 0.31% (n535) for medication abortion, 0.16% (n557) for first-trimester aspiration abortion, and 0.41% (n534) for second-trimester or later procedures. The total abortion-related complication rate including all sources of care including EDs and the original abortion facility was 2.1% (n51,156): 5.2% (n5588) for medication abortion, 1.3% (n5438) for first-trimester aspiration abortion, and 1.5% (n5130) for second-trimester or later procedures. CONCLUSION: Abortion complication rates are comparable to previously published rates even when ED visits are included and there is no loss to follow-up.