OBJECTIVE: To examine birth outcomes and pregnancy complications in women with a history of anorexia nervosa. DESIGN: Prospective cohort study. SETTING: Nationwide study in Sweden. POPULATION: All primiparous women--discharged from hospital with a diagnosis of anorexia nervosa during 1973 to 1996--who gave birth during 1983 to 2002 (n = 1000) were compared with all non-anorexia nervosa primiparous women who gave birth during the same years (n = 827,582). METHOD: Register study with data from Medical Birth Registry and National Patient Discharge Register. MAIN OUTCOME MEASURES: Pre-eclampsia, instrumental delivery, prematurity, small for gestational age, birthweight, Apgar score and perinatal mortality. RESULTS: Main birth outcome measures in women with a history of anorexia nervosa were very similar to the main population. The only observed differences were a slightly lower mean birthweight and lower adjusted odds ratios for instrumental delivery in the anorexia nervosa group compared with the main population. Neither severity of the disease nor a shorter recovery phase after first hospitalisation was related to pregnancy complications or birth outcomes. CONCLUSION: A history of anorexia nervosa was not associated with negative birth outcomes. Thus, special obstetric monitoring of pregnant women with history of anorexia nervosa does not seem to be warranted in a country with a satisfactory maternity surveillance.