Intrapartum monitoring of high-risk deliveries with ST analysis of the fetal electrocardiogram: an observational study of 6010 deliveries.
OBJECTIVE
To evaluate the clinical use of ST analysis (STAN) for intrapartum monitoring of high-risk pregnancies.


METHODS
Prospective observational study.


METHODS
University hospital, Norway, 2004-2008.


METHODS
Singleton pregnancies with a gestational age above 35(+6) weeks.


METHODS
Analysis of maternal and neonatal outcomes for all deliveries according to the method of intrapartum monitoring.


METHODS
Prevalence of cord metabolic acidosis (pH < 7.05, extracellular fluid base deficit (extracellular fluid) >12 mmol/L).


RESULTS
Of 23 203 deliveries, 6010 (25.9%) were monitored with STAN. Fetal blood sampling was performed in 146 (2.4%) of the 6010 cases. During the study period, the prevalence of cord metabolic acidosis and moderate cord acidosis (pH < 7.15) decreased in STAN-monitored deliveries from 1.4 to 0.3% (p = 0.01) and from 16.4 to 11.7% (p = 0.001), respectively. The prevalence of moderate and severe neonatal encephalopathy was 0.38%. In the birth population, the proportion of cesarean deliveries decreased from 10.1 to 8.8%. The risk of emergency cesarean section after STAN monitoring compared with those monitored with auscultation/cardiotocography was high (odds ratio 5.4, 95% confidence interval = 4.9-6.1) but remained stable during the study period.


CONCLUSIONS
ST analysis is a useful tool for identification of fetuses at risk of intrapartum hypoxia. Despite the restricted use of fetal blood sampling, we found a low proportion of cord metabolic acidosis and newborn morbidity.
Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway. jorg.kessler@kk.uib.no
Jörg
J
Kessler
Dag
D
Moster
Susanne
S
Albrechtsen
D000138:Acidosis / Q000097:blood; D000328:Adult; D015148:Cardiotocography / Q000379:methods*; D002585:Cesarean Section / Q000706:statistics & numerical data; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018566:Pregnancy, High-Risk; D015995:Prevalence; D011446:Prospective Studies