title: A randomised clinical trial on cardiotocography plus fetal blood sampling versus cardiotocography plus ST-analysis of the fetal electrocardiogram (STAN) for intrapartum monitoring.
abstract: BACKGROUND
  Cardiotocography (CTG) is worldwide the method for fetal surveillance during labour. However, CTG alone shows many false positive test results and without fetal blood sampling (FBS), it results in an increase in operative deliveries without improvement of fetal outcome. FBS requires additional expertise, is invasive and has often to be repeated during labour. Two clinical trials have shown that a combination of CTG and ST-analysis of the fetal electrocardiogram (ECG) reduces the rates of metabolic acidosis and instrumental delivery. However, in both trials FBS was still performed in the ST-analysis arm, and it is therefore still unknown if the observed results were indeed due to the ST-analysis or to the use of FBS in combination with ST-analysis.
  
  
  METHODS
  We aim to evaluate the effectiveness of non-invasive monitoring (CTG + ST-analysis) as compared to normal care (CTG + FBS), in a multicentre randomised clinical trial setting. Secondary aims are: 1) to judge whether ST-analysis of fetal electrocardiogram can significantly decrease frequency of performance of FBS or even replace it; 2) perform a cost analysis to establish the economic impact of the two treatment options. Women in labour with a gestational age > or = 36 weeks and an indication for CTG-monitoring can be included in the trial. Eligible women will be randomised for fetal surveillance with CTG and, if necessary, FBS or CTG combined with ST-analysis of the fetal ECG. The primary outcome of the study is the incidence of serious metabolic acidosis (defined as pH < 7.05 and Bdecf > 12 mmol/L in the umbilical cord artery). Secondary outcome measures are: instrumental delivery, neonatal outcome (Apgar score, admission to a neonatal ward), incidence of performance of FBS in both arms and cost-effectiveness of both monitoring strategies across hospitals. The analysis will follow the intention to treat principle. The incidence of metabolic acidosis will be compared across both groups. Assuming a reduction of metabolic acidosis from 3.5% to 2.1 %, using a two-sided test with an alpha of 0.05 and a power of 0.80, in favour of CTG plus ST-analysis, about 5100 women have to be randomised. Furthermore, the cost-effectiveness of CTG and ST-analysis as compared to CTG and FBS will be studied.
  
  
  CONCLUSIONS
  This study will provide data about the use of intrapartum ST-analysis with a strict protocol for performance of FBS to limit its incidence. We aim to clarify to what extent intrapartum ST-analysis can be used without the performance of FBS and in which cases FBS is still needed.
  
  
  BACKGROUND
  ISRCTN95732366.
authors.affiliation: Department of Obstetrics and Gynaecology, University Medical Center Utrecht, The Netherlands. M.E.M.H.Westerhuis@umcutrecht.nl
authors.forename: Michelle E M H
authors.initials: ME
authors.lastname: Westerhuis
authors.forename: Karel G M
authors.initials: KG
authors.lastname: Moons
authors.forename: Erik
authors.initials: E
authors.lastname: van Beek
authors.forename: Saskia M
authors.initials: SM
authors.lastname: Bijvoet
authors.forename: Addy P
authors.initials: AP
authors.lastname: Drogtrop
authors.forename: Herman P
authors.initials: HP
authors.lastname: van Geijn
authors.forename: Jan M M
authors.initials: JM
authors.lastname: van Lith
authors.forename: Ben W J
authors.initials: BW
authors.lastname: Mol
authors.forename: Jan G
authors.initials: JG
authors.lastname: Nijhuis
authors.forename: S Guid
authors.initials: SG
authors.lastname: Oei
authors.forename: Martina M
authors.initials: MM
authors.lastname: Porath
authors.forename: Robbert J P
authors.initials: RJ
authors.lastname: Rijnders
authors.forename: Nico W E
authors.initials: NW
authors.lastname: Schuitemaker
authors.forename: Ingeborg
authors.initials: I
authors.lastname: van der Tweel
authors.forename: Gerard H A
authors.initials: GH
authors.lastname: Visser
authors.forename: Christine
authors.initials: C
authors.lastname: Willekes
authors.forename: Anneke
authors.initials: A
authors.lastname: Kwee
mesh_terms: D000138:Acidosis / Q000097:blood / Q000209:etiology; D001238:Asphyxia Neonatorum / Q000517:prevention & control; D001784:Blood Gas Analysis / Q000191:economics / Q000379:methods; D015148:Cardiotocography / Q000191:economics / Q000379:methods; D003362:Cost-Benefit Analysis; D004562:Electrocardiography / Q000191:economics / Q000379:methods; D005260:Female; D005312:Fetal Blood; D005311:Fetal Hypoxia / Q000097:blood / Q000175:diagnosis*; D005323:Fetal Monitoring / Q000191:economics* / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy