title: Randomized double-blind comparison of the effects of intramyometrial and intravenous oxytocin during elective cesarean section.
abstract: OBJECTIVE
  Obstetricians sometimes administer intramyometrial oxytocin to stimulate uterine contraction during cesarean section, but its effects have not been well investigated. We performed a randomized, double-blind study to test the hypothesis that a small dose of intramyometrial oxytocin would induce acceptable uterine contractility more quickly and with fewer hemodynamic side-effects than the same dose administered intravenously.
  
  
  METHODS
  Forty women with a single fetus at ≥36 weeks of gestational age scheduled for elective cesarean section under spinal anesthesia were randomized to the intravenous and intramyometrial groups to receive oxytocin at 0.07 IU/kg. The drug was administered immediately after umbilical cord clamping. Systolic blood pressure, heart rate, intraoperative blood loss, uterine tone, total amount of intraoperative oxytocin, and additional uterotonic drugs administered in the first 24 h were compared.
  
  
  RESULTS
  Maximum uterine contractility was achieved after 2 and 10 min for the intravenous and intramyometrial groups, respectively. The mean hemodynamic parameters of the intramyometrial group were stable. In contrast, the intravenous group showed a reduction in systolic blood pressure after 2-4 min and increased heart rate after 1-2 min. Intraoperative blood loss, total oxytocin dose, and frequency of additional uterotonic drugs were comparable between the two groups.
  
  
  CONCLUSIONS
  Although intraoperative blood loss was comparable, a small dose of intramyometrial oxytocin was inappropriate to obtain a prompt and acceptable uterine contraction during cesarean section.
authors.affiliation: Perinatal Medical Center, Hamamatsu University Hospital, Hamamatsu, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Akinaga
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Uchizaki
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Kurita
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Taniguchi
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Makino
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Uchida
authors.affiliation: Perinatal Medical Center, Hamamatsu University Hospital, Hamamatsu, Japan.
authors.forename: Kazunao
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Perinatal Medical Center, Hamamatsu University Hospital, Hamamatsu, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Itoh
authors.affiliation: Department of Biomedical Informatics, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Tani
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Shigehito
authors.initials: S
authors.lastname: Sato
authors.affiliation: Division of Obstetric Anesthesia, Center for Maternal, Fetal, and Neonatal Medicine, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: Katsuo
authors.initials: K
authors.lastname: Terui
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical; D002585:Cesarean Section / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D009215:Myometrium / Q000187:drug effects; D010121:Oxytocin / Q000008:administration & dosage*; D011247:Pregnancy; D013997:Time Factors; D014590:Uterine Contraction
chemical_list: D010121:Oxytocin
keywords: cesarean section; intramyometrial administration; intravenous administration; oxytocin; uterine contraction