Identification of cases with adverse neonatal outcome monitored by cardiotocography versus ST analysis: secondary analysis of a randomized trial.

OBJECTIVE: To evaluate whether correct adherence to clinical guidelines might have led to prevention of cases with adverse neonatal outcome. DESIGN: Secondary analysis of cases with adverse outcome in a multicenter randomized clinical trial. SETTING: Nine Dutch hospitals. POPULATION: Pregnant women with a term singleton fetus in cephalic position. METHODS: Data were obtained from a randomized trial that compared monitoring by STAN® (index group) with cardiotocography (control group). In both trial arms, three observers independently assessed the fetal surveillance results in all cases with adverse neonatal outcome, to determine whether an indication for intervention was present, based on current clinical guidelines. MAIN OUTCOME MEASURES: Adverse neonatal outcome cases fulfilled one or more of the following criteria: (i) metabolic acidosis in umbilical cord artery (pH < 7.05 and base deficit in extracellular fluid >12 mmol/L); (ii) umbilical cord artery pH < 7.00; (iii) perinatal death; and/or (iv) signs of moderate or severe hypoxic ischemic encephalopathy. RESULTS: We studied 5681 women, of whom 61 (1.1%) had an adverse outcome (26 index; 35 control). In these women, the number of performed operative deliveries for fetal distress was 18 (69.2%) and 16 (45.7%), respectively. Reassessment of all 61 cases showed that there was a fetal indication to intervene in 23 (88.5%) and 19 (57.6%) cases, respectively. In 13 (50.0%) vs. 11 (33.3%) cases, respectively, this indication occurred more than 20 min before the time of delivery, meaning that these adverse outcomes could possibly have been prevented. CONCLUSIONS: In our trial, more strict adherence to clinical guidelines could have led to additional identification and prevention of adverse outcome.

Prediction of neonatal metabolic acidosis in women with a singleton term pregnancy in cephalic presentation.

We sought to predict neonatal metabolic acidosis at birth using antepartum obstetric characteristics (model 1) and additional characteristics available during labor (model 2). In 5667 laboring women from a multicenter randomized trial that had a high-risk singleton pregnancy in cephalic presentation beyond 36 weeks of gestation, we predicted neonatal metabolic acidosis. Based on literature and clinical reasoning, we selected both antepartum characteristics and characteristics that became available during labor. After univariable analyses, the predictors of the multivariable models were identified by backward stepwise selection in a logistic regression analysis. Model performance was assessed by discrimination and calibration. To correct for potential overfitting, we (internally) validated the models with bootstrapping techniques. Of 5667 neonates born alive, 107 (1.9%) had metabolic acidosis. Antepartum predictors of metabolic acidosis were gestational age, nulliparity, previous cesarean delivery, and maternal diabetes. Additional intrapartum predictors were spontaneous onset of labor and meconium-stained amniotic fluid. Calibration and discrimination were acceptable for both models (c-statistic 0.64 and 0.66, respectively). In women with a high-risk singleton term pregnancy in cephalic presentation, we identified antepartum and intrapartum factors that predict neonatal metabolic acidosis at birth.

Predictive value of the baseline T-QRS ratio of the fetal electrocardiogram in intrapartum fetal monitoring: a prospective cohort study.

OBJECTIVE: To evaluate the added value of the baseline T/QRS ratio to other known risk factors in predicting adverse outcome and interventions for suspected fetal distress. DESIGN: Prospective cohort study. SETTING: Three academic and six non-academic teaching hospitals in the Netherlands. POPULATION: Laboring women with a high-risk cephalic singleton pregnancy beyond 36 weeks of gestation. METHODS: We obtained STAN(®) recordings (ST-analysis, Neoventa, Sweden) from two previous studies. Three patient groups were defined: cases with adverse outcome, cases with emergency delivery because of suspected fetal distress without adverse outcome, and a reference group of uncomplicated cases. Baseline T/QRS ratios among the adverse outcome and intervention for suspected fetal distress cases were compared to those of the uncomplicated cases. The ability of baseline T/QRS to predict adverse outcome and suspected fetal distress was determined using a multivariable logistic model. MAIN OUTCOME MEASURES: The added value of the baseline T/QRS to other known risk factors in the prediction of adverse outcome and interventions for suspected fetal distress. RESULTS: From 3462 recordings, 2459 were available for analysis. Median baseline T/QRS for uncomplicated cases, adverse outcome and interventions for suspected fetal distress were 0.12 (range 0.00-0.52), 0.12 (0.00-0.42) and 0.13 (0.00-0.39), respectively. There was no statistical difference between these groups. Multivariable analysis showed no added value of baseline T/QRS in the prediction of either adverse outcome or interventions for suspected fetal distress. CONCLUSION: Baseline T/QRS has no added value in the prediction of adverse neonatal outcome or interventions for suspected fetal distress.

Cost-effectiveness of cardiotocography plus ST analysis of the fetal electrocardiogram compared with cardiotocography only.

OBJECTIVE: To assess the cost-effectiveness of addition of ST analysis of the fetal electrocardiogram (ECG; STAN) to cardiotocography (CTG) for fetal surveillance during labor compared with CTG only. DESIGN: Cost-effectiveness analysis based on a randomized clinical trial on ST analysis of the fetal ECG. SETTING: Obstetric departments of three academic and six general hospitals in The Netherlands. Population. Laboring women with a singleton high-risk pregnancy, a fetus in cephalic presentation, a gestational age >36 weeks and an indication for internal electronic fetal monitoring. METHODS: A trial-based cost-effectiveness analysis was performed from a health-care provider perspective. MAIN OUTCOME MEASURES: Primary health outcome was the incidence of metabolic acidosis measured in the umbilical artery. Direct medical costs were estimated from start of labor to childbirth. Cost-effectiveness was expressed as costs to prevent one case of metabolic acidosis. RESULTS: The incidence of metabolic acidosis was 0.7% in the ST-analysis group and 1.0% in the CTG-only group (relative risk 0.70; 95% confidence interval 0.38-1.28). Per delivery, the mean costs per patient of CTG plus ST analysis (n= 2 827) were €1,345 vs. €1,316 for CTG only (n= 2 840), with a mean difference of €29 (95% confidence interval -€9 to €77) until childbirth. The incremental costs of ST analysis to prevent one case of metabolic acidosis were €9 667. CONCLUSIONS: The additional costs of monitoring by ST analysis of the fetal ECG are very limited when compared with monitoring by CTG only and very low compared with the total costs of delivery.

Cardiotocography plus ST analysis of fetal electrocardiogram compared with cardiotocography only for intrapartum monitoring: a randomized controlled trial.

OBJECTIVE: To estimate the effectiveness of intrapartum fetal monitoring by cardiotocography plus ST analysis using a strict protocol for performance of fetal blood sampling. METHODS: We performed a multicenter randomized trial among laboring women with a high-risk singleton pregnancy in cephalic presentation beyond 36 weeks of gestation. Participants were assigned to monitoring by cardiotocography with ST analysis (index) or cardiotocography only (control). Primary outcome was metabolic acidosis, defined as an umbilical cord artery pH below 7.05 combined with a base deficit calculated in the extracellular fluid compartment above 12 mmol/L. Secondary outcomes were metabolic acidosis in blood, operative deliveries, Apgar scores, neonatal admissions, and hypoxic-ischemic encephalopathy. RESULTS: We randomly assigned 5,681 women to the two groups (2,832 index, 2,849 control). The fetal blood sampling rate was 10.6% in the index compared with 20.4% in the control group (relative risk 0.52; 95% [CI] 0.46-0.59). The primary outcome occurred 0.7% in the index compared with 1.1% in the control group (relative risk 0.70; 95% CI 0.38-1.28; number needed to treat 252). Using metabolic acidosis calculated in blood, these rates were 1.6% and 2.6%, respectively (relative risk 0.63; 95% CI 0.42-0.94; number needed to treat 100). The number of operative deliveries, low Apgar scores, neonatal admissions, and newborns with hypoxic-ischemic encephalopathy was comparable in both groups. CONCLUSION: Intrapartum monitoring by cardiotocography combined with ST analysis does not significantly reduce the incidence of metabolic acidosis calculated in the extracellular fluid compartment. It does reduce the incidence of metabolic acidosis calculated in blood and the need for fetal blood sampling without affecting the Apgar score, neonatal admissions, hypoxic-ischemic encephalopathy, or operative deliveries. LEVEL OF EVIDENCE: I.

Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks' gestation (HYPITAT): a multicentre, open-label randomised controlled trial.

BACKGROUND: Robust evidence to direct management of pregnant women with mild hypertensive disease at term is scarce. We investigated whether induction of labour in women with a singleton pregnancy complicated by gestational hypertension or mild pre-eclampsia reduces severe maternal morbidity. METHODS: We undertook a multicentre, parallel, open-label randomised controlled trial in six academic and 32 non-academic hospitals in the Netherlands between October, 2005, and March, 2008. We enrolled patients with a singleton pregnancy at 36-41 weeks' gestation, and who had gestational hypertension or mild pre-eclampsia. Participants were randomly allocated in a 1:1 ratio by block randomisation with a web-based application system to receive either induction of labour or expectant monitoring. Masking of intervention allocation was not possible. The primary outcome was a composite measure of poor maternal outcome--maternal mortality, maternal morbidity (eclampsia, HELLP syndrome, pulmonary oedema, thromboembolic disease, and placental abruption), progression to severe hypertension or proteinuria, and major post-partum haemorrhage (>1000 mL blood loss). Analysis was by intention to treat and treatment effect is presented as relative risk. This study is registered, number ISRCTN08132825. FINDINGS: 756 patients were allocated to receive induction of labour (n=377 patients) or expectant monitoring (n=379). 397 patients refused randomisation but authorised use of their medical records. Of women who were randomised, 117 (31%) allocated to induction of labour developed poor maternal outcome compared with 166 (44%) allocated to expectant monitoring (relative risk 0.71, 95% CI 0.59-0.86, p<0.0001). No cases of maternal or neonatal death or eclampsia were recorded. INTERPRETATION: Induction of labour is associated with improved maternal outcome and should be advised for women with mild hypertensive disease beyond 37 weeks' gestation. FUNDING: ZonMw.

A randomised clinical trial on cardiotocography plus fetal blood sampling versus cardiotocography plus ST-analysis of the fetal electrocardiogram (STAN) for intrapartum monitoring.

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/DESIGN: 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. DISCUSSION: 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. TRIAL REGISTRATION NUMBER: ISRCTN95732366.