OBJECTIVE: To study the factors associated with the formation of striae gravidarum and the measures used by women to prevent them. DESIGN: Retrospective cohort study. SETTING: One private and one teaching hospital in St Paul, Minn. PARTICIPANTS: Forty-eight nulliparous women at 34 to 36 weeks' estimated gestational age attending prenatal classes or tours of the labor and delivery departments. INTERVENTIONS: None. MAIN OUTCOME MEASURE: Presence of abdominal striae. RESULTS: Women with abdominal striae were significantly younger, more likely to receive state medical assistance, more likely to have hip striae, and had a greater total weight gain than women without abdominal striae. Results of diabetes screening tests and glycosylated hemoglobin levels were similar in women with and without striae. Although most women attempted to prevent striae formation, women who used oils or creams formed striae as frequently as those who did not. CONCLUSIONS: A previously reported association between increased striae and glucose intolerance, which led to the theory of adrenal cortical hyperactivity as a cause of striae gravidarum, was not confirmed by this study. Many women use creams or oils in an attempt to prevent striae formation despite their ineffectiveness.