OBJECTIVES: To perform the first population-based measurement of clinical and economic outcomes after thyroid and parathyroid surgery in pregnant women and identify the characteristics of this population and the predictors of outcome. DESIGN: Retrospective cross-sectional study. SETTING: Health Care Utilization Project Nationwide Inpatient Sample (HCUP-NIS), a 20% sample of nonfederal US hospitals. PATIENTS: All pregnant women, compared with age-matched nonpregnant women, who underwent thyroid and parathyroid procedures from 1999 to 2005. MAIN OUTCOME MEASURES: Fetal, maternal, and surgical complications, in-hospital mortality, median length of stay, and hospital costs. RESULTS: A total of 201 pregnant women underwent thyroid (n = 165) and parathyroid (n = 36) procedures and were examined together. The mean age was 29 years, 60% were white, 25% were emergent or urgent admissions, and 46% had thyroid cancer. Compared with nonpregnant women (n = 31 155), pregnant patients had a higher rate of endocrine (15.9 vs 8.1%; P < .001) and general complications (11.4 vs 3.6%; P < .001), longer unadjusted lengths of stay (2 days vs 1 day; P < .001), and higher unadjusted hospital costs ($6873 vs $5963; P = .007). The fetal and maternal complication rates were 5.5% and 4.5%, respectively. On multivariate regression analysis, pregnancy was an independent predictor of higher combined surgical complications (odds ratio, 2; P < .001), longer adjusted length of stay (0.3 days longer; P < .001), and higher adjusted hospital costs ($300; P < .001). Other independent predictors of outcome were surgeon volume, patient race or ethnicity, and insurance status. CONCLUSIONS: Pregnant women have worse clinical and economic outcomes following thyroid and parathyroid surgery than nonpregnant women, with disparities in outcomes based on race, insurance, and access to high-volume surgeons.