According to data presented at the American Congress of Obstetricians and Gynecologists' 58th Annual Clinical Meeting in San Francisco, underweight pregnant women are more likely to be admitted for preterm contractions than normal weight or overweight women. Mihai Muredan, MD, and Neal Ipema, MD, of Resurrection Healthcare, St. Joseph Hospital in Chicago, conducted a retrospective cohort study of patients who presented for preterm contractions from 2000 through 2008. The body mass index (BMI) categories were <19 as underweight, 20-25 as normal, and >25 as overweight. Preterm contractions were documented using an external tocodynamometer. Exclusion criteria included pregnancies with multiple gestations, gestational age <24 weeks or >37 weeks, neonatal anomalies, and premature rupture of membrane. Chi-square testing compared the probability of admission as a function of weight groups as well as variable of age and race. Of 840 patients identified with preterm contractions, 7% were admitted while 93% were discharged. Of the total patients, 15% were underweight, 43% were of normal weight, and 42% were classified as overweight. Following data analysis, Drs. Muredan and Ipema found that admission for preterm contractions was highest in the underweight (95%), followed by normal weight patients (5%). None of those admitted were overweight. Probability models showed that normal weight patients were less likely to be admitted for preterm contractions compared with underweight patients even after controlling for age and race. In other research presented at the meeting, investigators from Thomas Jefferson University in Philadelphia showed that women who undergo bariatric surgery for the purpose of permanent weight loss tend to do better during pregnancy than women who have not undergone bariatric surgery.