Outcomes after internal versus external tocodynamometry for monitoring labor.
BACKGROUND
It has been hypothesized that internal tocodynamometry, as compared with external monitoring, may provide a more accurate assessment of contractions and thus improve the ability to adjust the dose of oxytocin effectively, resulting in fewer operative deliveries and less fetal distress. However, few data are available to test this hypothesis.


METHODS
We performed a randomized, controlled trial in six hospitals in The Netherlands to compare internal tocodynamometry with external monitoring of uterine activity in women for whom induced or augmented labor was required. The primary outcome was the rate of operative deliveries, including both cesarean sections and instrumented vaginal deliveries. Secondary outcomes included the use of antibiotics during labor, time from randomization to delivery, and adverse neonatal outcomes (defined as any of the following: an Apgar score at 5 minutes of less than 7, umbilical-artery pH of less than 7.05, and neonatal hospital stay of longer than 48 hours).


RESULTS
We randomly assigned 1456 women to either internal tocodynamometry (734) or external monitoring (722). The operative-delivery rate was 31.3% in the internal-tocodynamometry group and 29.6% in the external-monitoring group (relative risk with internal monitoring, 1.1; 95% confidence interval [CI], 0.91 to 1.2). Secondary outcomes did not differ significantly between the two groups. The rate of adverse neonatal outcomes was 14.3% with internal monitoring and 15.0% with external monitoring (relative risk, 0.95; 95% CI, 0.74 to 1.2). No serious adverse events associated with use of the intrauterine pressure catheter were reported.


CONCLUSIONS
Internal tocodynamometry during induced or augmented labor, as compared with external monitoring, did not significantly reduce the rate of operative deliveries or of adverse neonatal outcomes. (Current Controlled Trials number, ISRCTN13667534; Netherlands Trial number, NTR285.)
Bakker
Jannet J H
JJ
Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands. j.j.bakker@amc.uva.nl
Verhoeven
Corine J M
CJ
Janssen
Petra F
PF
van Lith
Jan M
JM
van Oudgaarden
Elisabeth D
ED
Bloemenkamp
Kitty W M
KW
Papatsonis
Dimitri N M
DN
Mol
Ben Willem J
BW
van der Post
Joris A M
JA
D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data*; D005113:Extraction, Obstetrical / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007751:Labor, Induced; D007743:Labor, Obstetric; D011247:Pregnancy; D011256:Pregnancy Outcome; D018709:Statistics, Nonparametric; D018590:Uterine Monitoring / Q000295:instrumentation / Q000379:methods*