Table of Contents
ISRN Obstetrics and Gynecology
Volume 2013 (2013), Article ID 873563, 6 pages
Research Article

Survival Rate of Extremely Low Birth Weight Infants and Its Risk Factors: Case-Control Study in Japan

1Perinatal Medical Center, Tokyo Women’s Medical University Hospital, Kawadacho 8-1, Shinjuku, Tokyo 1628666, Japan
2Department of Obstetrics and Gynecology, Tokyo Women’s Medical University, Tokyo 1628666, Japan

Received 6 September 2013; Accepted 9 October 2013

Academic Editors: C. Iavazzo and M. C. Klein

Copyright © 2013 Masaki Ogawa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Aim. To clarify the effect of perinatal events on the survival of ELBW infants in Japan. Methods. 1,713 ELBW infants, from 92,630 live births in 2001 and 2002, born at 22–36 weeks of gestation were registered. Case was defined as death at discharge. The relevant variables were compared between the cases ( ) and the controls ( ). Results. The total survival rate was 78.6%. There was a significant difference between the survival rate in cesarean and vaginal delivery at 24–31 weeks of gestation. Cesarean delivery in infants with a birth weight >400 g was significantly advantageous to the survival rate of ELBW infants than vaginal delivery. The significant contributing factors were gestational age at delivery (OR: 0.97), Apgar score at 5 min (0.56), antenatal steroid (0.41), and birth weight (0.996). Nonvertex presentation (1.81), vaginal delivery (1.56), and placental abruption (2.50) were found to be significantly associated with neonatal death. Conclusions. Cesarean section might be advantageous for survival in ELBW infants over 24 gestational weeks or 400 grams of birth weight. Nonvertex presentation, vaginal delivery, and placental abruption could be significant risk factors for survival of ELBW infants.