Oxitocina

Reviews
OBSTETRICS

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High-dose vs low-dose oxytocin for labor augmentation: a systematic review
Shu-Qin Wei, MD, PhD; Zhong-Cheng Luo, MD, PhD; Hui-Ping Qi, MD, MSc; Hairong Xu, MD, MSc; William D. Fraser, MD, MSc augmentation of labor on method of delivery and on indicators of maternal and neonatal morbidity.

The objective of this systematic review was to estimate theefficacy and safety of high-dose vs low-dose oxytocin for labor augmentation on the risk of cesarean section and on indicators of maternal and neonatal morbidity. We searched PubMed, MEDLINE, EMBASE, and the Cochrane Library for randomized clinical trials published until January 2010. Ten randomized clinical trials, including 5423 women, met the inclusion criteria. High-dose oxytocin was associated witha moderate decrease in the risk of cesarean section (relative risk [RR], 0.85; 95% confidence interval [CI], 0.75– 0.97), a small increase in spontaneous vaginal delivery (RR, 1.07; 95% CI, 1.02–1.12), and a decrease in labor duration (mean difference: –1.54 hours, 95% CI, –2.44 to – 0.64). While hyperstimulation was increased with high-dose oxytocin (RR, 1.91; 95% CI, 1.49 –2.45), there was noevidence of an increase in maternal or neonatal morbidity. We conclude that high-dose oxytocin for labor augmentation is associated with a decrease in cesarean section and shortened labor. Key words: active management, augmentation, oxytocin dose

M ATERIALS AND M ETHODS
Data sources A comprehensive literature search was performed using several search strategies. Published studies were identifiedthrough manual searches and through a computerized search of the Cochrane Collaboration Pregnancy and Childbirth Group Trial Register, PubMed, MEDLINE, and EMBASE in any language until January 2010. The key words were: oxytocin, dose, active management of labor (AML), randomized clinical trials, augmentation, and labor. References cited in these articles were manually searched to obtain additionalarticles. Study selection Two investigators (S-Q.W. and H-P.Q.) independently scrutinized the electronic searches and obtained full manuscripts of all citations that were potentially eligible studies for inclusion. Included studies had to meet the following criteria. (1) Study design was a randomized controlled trial. (2) Population consisted of pregnant women in spontaneous labor and withoutprior use of oxytocin. (3) The study contrasted 2 interventions for labor augmentation: high-dose vs low-dose oxytocin. “High dose” was defined as an initial dose of 4 mU/min and dose increments of at least 4 mU/min; “low-dose” protocols were defined as those with an initial dose ranging between 1-4 mU/min with increments of 1-2 mU/min. (4) Outcomes measured at least 1 of the following: cesareansection, spontaneous vaginal delivery, operative vaginal delivery, duration of labor, hyperstimulation, postpartum hemorrhage, use of epidural analgesia, maternal blood transfusion, Apgar score, and neonatal complications.

T

hei rise in cesarean section continues to be a matter of obstetric concern.1 Recent reports suggest that high cesarean rates may have an adverse impact on maternal and neonatalmorbidity and mortality.2 Dystocia is the leading indication for
From the Department of Obstetrics and Gynecology, Saint-Justine Hospital, University of Montreal, Montreal, Quebec, Canada (Drs Wei, Luo, Xu, and Fraser); and Department of Obstetrics and Gynecology, the First Affiliated Hospital, Harbin Medical University, Harbin, China (Drs Wei and Qi).
Received Jan. 6, 2010; revised Feb. 19,2010; accepted March 3, 2010. Reprints: William D. Fraser, MD, MSc, Department of Obstetrics and Gynecology, Université de Montréal, 3175 Chemin de la Côte Sainte-Catherine, Montreal (Quebec), Canada H3T 1C5. william.fraser@umontreal.ca. Dr Fraser was supported by a Canada Research Chair from the Canadian Institutes of Health Research (CIHR), Drs Wei and Xu by a scholarship from the CIHR...