and risk of spontaneous preterm delivery Bo Jacobsson, Anne Lise Brantster, Hakon K. Gjessing, Solveig Myking, Helle Margrete Meltzer, Margareta Haugen, Ronny Myhre Sahlgrenska University Hospital, Department of Obstetrics and Gynecology, Gothenburg, Sweden, Norwegian Institute of Public Health, Division of Environmental Medicine, Oslo, Norway, Norwegian Institute of Public Health, Division of Epidemiology, Oslo, Norway OBJECTIVE: Several studies have found that microbial invasion of the amniotic fluid during pregnancy is associated with preterm delivery. The use of antibiotic interventions and treatments has had less effect than anticipated. Some food contains components with antimicrobial activity. Current knowledge on potential influence of antimicrobial components in food on pregnancy complications caused by microbes is limited. We hypothesized that intake of food with antimicrobial components might influence and reduce pregnancy complications caused by some pathogenic microorganisms and in this study we investigate the influence of food with known antimicrobial components on the rate of spontaneous preterm delivery. STUDY DESIGN: We studied dietary food intake using the prospective Norwegian Mother Child Cohort for the pregnancy outcome spontaneous preterm delivery ( 37 weeks). First we performed a literature search to identify different microbes involved in pregnancy complications associated with spontaneous preterm delivery. Secondly we identified food types included in the cohort’s food frequencies questionnaire that contained known antimicrobial components active towards microbes assumed to be associated with spontaneous preterm delivery. Data were analyzed using binary logistic regression method with covariates maternal age, parity, BMI before pregnancy, marital status, smoking prior to pregnancy and education level. RESULTS: In the adjusted model, the food types garlic / onion / leek (p 0.028) and dried fruits (p 0.005) were associated in a dose-dependent manner with lower spontaneous preterm delivery rate. Home made salad dressing with oil (p 0.031) and green tea (p 0.059) showed a borderline significant risk reduction. CONCLUSION: Dietary intake of certain food with known antimicrobial compounds was associated with lower risk of spontaneous preterm delivery. However unable to other than speculate in the biological effect of these food types they do contain antimicrobial components known to be active towards some pathogens which are involved in pregnancy conditions associated with spontaneous preterm delivery. 466 17-hydroxyprogesterone caproate for women with history of preterm birth in a prior pregnancy and twins in the current pregnancy C. Andrew Combs, Thomas J. Garite, Kimberly Maurel, Deborah Cebrik, For the Obstetrix Collaborative Research Network Obstetrix Medical Group, Center for Research, Education, & Quality, Sunrise, FL, Obstetrix Medical Group twins trial, Axistat, Inc., Biostatistics, San Francisco, CA OBJECTIVE: Prophylactic 17-hydroxyprogesterone caproate (17P) reduces risk of preterm birth (PTB) in singleton pregnancies with maternal history of prior PTB but does not reduce PTB in unselected twin pregnancies. We sought to determine whether 17P will reduce the rate of PTB among a subset of twin pregnancies with a maternal history of PTB in a prior pregnancy. STUDY DESIGN: Secondary analysis of the Obstetrix double-blinded, randomized trial of 17P (250 mg weekly) versus placebo in dichorionic-diamniotic twins. Among 238 analyzable subjects, 29 reported a history of PTB. We compared gestational age (GA) at delivery and latency (randomization-to-delivery interval) of the 17P versus placebo groups in 3 subsets: those with history of PTB, parous women without history of PTB, and nulliparas. RESULTS: Median delivery GA and latency were similar in all 3 subsets (Table). There were no statistically significant differences in delivery GA or latency between 17P and placebo groups in any subset. CONCLUSION: We found no evidence that 17P prolonged twin pregnancy, even with a maternal history of PTB in a prior pregnancy. A trial with larger numbers or a metaanalysis of completed trials of 17P for twins may give further insight into this question.