218 Umbilical cord blood is increasingly used as an alterna- tive source of hematopoietic stem cells for related 1 and un- related 2 allogeneic transplantation in children and adoles- cents. Recent data show that clinical outcome of cord blood transplantation is influenced by the number of nu- cleated cells transplanted. 3, 4 Therefore the yield of stem cells remains an important aim of cord blood collection in addition to donor (ie, maternal and neonatal) safety. The strategy of cord blood collection varies between different cord blood banks. 5 Open systems, which were initially used for cord blood retrieval, 6 have been re- placed by closed systems with blood-collection bags to minimize the risk of contamination with bacteria or ma- ternal cells. 7 Some authors described cord blood collec- tion at vaginal delivery after expulsion of the placenta, 8 whereas others perform the collection while the placenta is still in utero 9 or use a combination of the two. 6 In a ran- domized trial we previously showed that cord blood col- lection during vaginal delivery is improved if performed before placental expulsion. 10 If a cesarean delivery is per- formed for obstetric reasons, an optimal collection tech- nique is also essential, especially if cord blood transplan- tation in a sibling is planned. There are, however, no prospective data about different cord blood-collection methods during cesarean delivery available to date. The aim of our study was to assess, in a randomized trial, whether cord blood collection before delivery of the placenta during cesarean delivery is superior to sampling from the delivered placenta by using a single umbilical vein puncture and a closed blood-collection system. Methods Study design. Pregnant women undergoing cesarean delivery at the Department of Obstetrics and Gynecology of the University Hospital of Basel were considered for in- clusion into the study. Criteria for inclusion were single- ton pregnancy, elective or secondary cesarean delivery, and willingness to participate in the study. Exclusion cri- From the Department of Obstetrics and Gynecology, a the Laboratory of Hematology, Department of Central Laboratories, b and the Division of Hematology, Department of Internal Medicine, c University of Basel. Received for publication July 29, 1999; revised December 2, 1999; accepted January 12, 2000. Reprint requests: Daniel V. Surbek, MD, Harris Birthright Research Cen- tre for Fetal Medicine, King’s College Hospital, Denmark Hill, London, United Kingdom SE5 9RS. Copyright © 2000 by Mosby, Inc. 0002-9378/2000 $12.00 + 0 6/1/105744 doi:10.1067/mob.2000.105744 Umbilical cord blood collection before placental delivery during cesarean delivery increases cord blood volume and nucleated cell number available for transplantation Daniel V. Surbek, MD, a Eva Visca, MD, a Christian Steinmann, MD, a André Tichelli, MD, b Stefan Schatt, a Sinuhe Hahn, PhD, a Alois Gratwohl, MD, c and Wolfgang Holzgreve, MD, MS a Basel, Switzerland OBJECTIVE: We sought to determine whether umbilical cord blood collection during cesarean delivery can be improved by collecting cord blood before delivery of the placenta. STUDY DESIGN: Patients undergoing cesarean delivery were randomly assigned to cord blood collection before or after placental delivery. Closed sterile collection systems were used for blood sampling. Cord blood characteristics and maternal outcome parameters were compared between the 2 groups. RESULTS: A total number of 40 patients were available for analysis. No differences in maternal and neonatal characteristics were found. A larger amount of cord blood volume (mean ± SEM, 93 ± 7.5 vs 66 ± 6.6 mL; P = .013) and total nucleated cell number (11.1 ± 1.2 vs 7.4 ± 0.8 × 10 8 cells; P = .026) was obtained in the samples collected before compared with those collected after placental delivery.Similarly, there was a trend toward higher total CD34 + cell number in samples collected in situ (30.0 ± 6.0 vs 17.4 ± 2.4 × 10 5 cells; P = .076). Estimated intraoperative blood loss, difference between prepartum and postpartum hemoglobin values, operating time, and puerperal infection rates were similar in both groups. CONCLUSION: If a cesarean delivery is performed, cord blood sampling is more efficacious if performed before delivery of the placenta. This collection method seems beneficial and safe and might therefore be preferably used for related, as well as unrelated, cord blood stem cell banking and transplantation. (Am J Obstet Gynecol 2000;183:218-21.) Key words: Umbilical cord blood, hematopoietic stem cells, cesarean delivery, cord blood collection