Lactate compared with pH analysis at fetal scalp blood sampling: a prospective randomised study. Determination of pH or lactate in fetal scalp blood in management of intrapartum fetal distress: randomised controlled multicentre trial. Intrapartum management of nonreassuring fetal heart rate patterns: a randomized controlled trial of fetal pulse oximetry. The Dublin randomized controlled trial of intrapartum fetal heart rate monitoring. A randomised controlled trial of simple compared with complex antenatal fetal monitoring after 42 weeks of gestation. A randomized study to assess two different techniques of aspiration while performing transabdominal chorionic villus sampling. Cardiotocography plus ST analysis of fetal electrocardiogram compared with cardiotocography only for intrapartum monitoring: a randomized controlled trial. Intrapartum fetal heart rate monitoring in a combined low- and high-risk population: a controlled clinical trial. A randomized trial of electronic fetal monitoring in preterm labor.
Fetal scalp blood sampling is a widely used method for assessing fetal condition in the event of ominous fetal heart rate patterns. The purpose of this randomised trial was to compare the value of fetal scalp blood lactate and pH management in cases of abnormal intrapartum fetal heart rate tracings.
                Of 341 cases of ominous fetal heart rate patterns, 169 were randomly assigned to pH analysis, and 172 to lactate measurements. Lactate was measured using a lactate card requiring 5 microL of blood and yielding the result within 60 seconds. pH analysis was performed with an ABL 510 acid-base analyser requiring 35 microL of blood and yielding the results within 47 seconds.
                Unsuccessful fetal blood sampling procedures (no result or an unreliable result) occurred significantly more often in the pH subgroup than in the lactate subgroup (OR 16.1 with 95% CI 5.8-44.7). In the pH subgroup the failure rate was inversely related to the degree of cervical dilatation. Compared with the pH subgroup, the lactate subgroup was characterised by fewer fetal scalp incisions per blood sampling attempt (median 1.0 [interquartile range (IQR) 1-1] vs 2.0 [IQR 1-2]), and significantly less time required for the sampling procedure (median 120 s [IQR 90-147] vs 230 s [IQR 180-300]). The groups did not differ in mode of delivery, neonatal outcome and umbilical artery acid-base balance and lactate levels.
                This trial showed the levels of lactate and pH in fetal scalp blood to be comparable in predicting perinatal outcome, but the procedure to measuring lactate was more successful than that for pH. Owing to its simplicity of performance, lactate analysis is an attractive alternative for intrapartum fetal monitoring. To examine the effectiveness of pH analysis of fetal scalp blood compared with lactate analysis in identifying hypoxia in labour to prevent acidaemia at birth.
                Randomised controlled multicentre trial.
                Labour wards.
                Women with a singleton pregnancy, cephalic presentation, gestational age >or=34 weeks, and clinical indication for fetal scalp blood sampling.
                Standard pH analysis (n=1496) or lactate analysis (n=1496) with an electrochemical microvolume (5 mul) test strip device. The cut-off levels for intervention were pH <7.21 and lactate >4.8 mmol/l, respectively.
                Metabolic acidaemia (pH <7.05 and base deficit >12 mmol/l) or pH <7.00 in cord artery blood.
                Metabolic acidaemia occurred in 3.2% in the lactate group and in 3.6% in the pH group (relative risk 0.91, 95% confidence interval 0.61 to 1.36). pH <7.00 occurred in 1.5% in the lactate group and in 1.8% in the pH group (0.84, 0.47 to 1.50). There was no significant difference in Apgar scores <7 at 5 minutes (1.15, 0.76 to 1.75) or operative deliveries for fetal distress (1.02, 0.93 to 1.11).
                There were no significant differences in rate of acidaemia at birth after use of lactate analysis or pH analysis of fetal scalp blood samples to determine hypoxia during labour.
                ISRCT No 1606064. We tested if fetal pulse oximetry in addition to electronic fetal monitoring (CTG) and scalp blood sampling improves the accuracy of fetal assessment and allows safe reduction of operative deliveries (-50%) and scalp blood sampling (-50%) performed because of nonreassuring fetal status. Study design A randomized controlled trial was conducted in 146 patients with term pregnancies in active labor and abnormal fetal heart rate patterns: 73 had electronic fetal heart rate monitoring (CTG) and fetal scalp blood sampling (control group), 73 had CTG, fetal scalp blood sampling, and continuous fetal pulse oximetry (study group).
                There was a reduction of -50% in operative deliveries and fetal scalp blood sampling performed because of nonreassuring fetal status in the study group: operative deliveries, study versus control 25/49 (P </= .001); fetal scalp sampling, study versus control 32/64 (P </= .001). An increase in cesarean sections because of dystocia in the study group did not change the net number of operative deliveries. There was no difference between the 2 groups in adverse maternal or neonatal outcomes, as well as for the end points of metabolic acidosis and need for resuscitation.
                There was a safe reduction in operative deliveries (-50%) and scalp blood sampling (-50%) performed because of nonreassuring fetal status. The increase in cesarean sections because of dystocia in the study group was a well-documented arrest of labor, but it did not change the total number of operative deliveries in this group. In a randomized controlled trial involving 12,964 women, a policy of continuous electronic intrapartum fetal heart monitoring was compared with an alternative policy of intermittent auscultation, both policies including an option to measure fetal scalp blood pH. Women allocated to electronic fetal heart monitoring had shorter labors and received less analgesia. The caesarean delivery rates were 2.4% for electronic fetal heart monitoring and 2.2% for intermittent auscultation but this small difference arose from the identification of nearly twice as many fetuses with low scalp pH (less than 7.20) in the electronic fetal heart monitoring group. The forceps delivery rate was 8.2% in the electronic fetal heart monitoring group compared with 6.3% in the intermittent auscultation group, and this excess was explained by more instrumental deliveries prompted by fetal heart rate abnormalities. There were 14 stillbirths and neonatal deaths in each group, with a similar distribution of causes. There were no apparent differences in the rates of low Apgar scores, need for resuscitation, or transfer to the special care nursery. Cases of neonatal seizures and persistent abnormal neurological signs followed by survival were twice as frequent in the intermittent auscultation group, and this differential effect was related to duration of labor. Follow-up at 1 year of babies who survived neonatal seizures revealed three clearly abnormal infants in each group. The implications of these findings for both theory and practice are discussed. To compare the impact on perinatal outcome of two different protocols for antenatal fetal monitoring after 42 weeks gestation.
                A prospective randomised controlled trial.
                Liverpool Maternity Hospital.
                One hundred and forty-five women with singleton, uncomplicated pregnancies after 42 weeks of gestation.
                Random allocation to fetal monitoring by either: 1. a modified biophysical profile comprising of computerised cardiotocography, amniotic fluid index, and assessment of fetal breathing, tone and gross body movements; or 2. standard cardiotocography and maximum pool depth.
                Cord pH at delivery, number of abnormal monitoring tests, intrapartum management, mode of delivery and neonatal outcome.
                There were significantly more abnormal antenatal monitoring results in the modified biophysical profile group (47.2% vs 20.5%; odds ratio = 3.5, 99% CI = 1.3-9.1). There were no differences in cord blood gases, neonatal outcome, or in outcomes related to labour and delivery between the two groups, but a trend towards more obstetric interventions in the modified biophysical profile group was noted. Amniotic fluid volume after 42 weeks was more likely to be labelled as abnormal with amniotic fluid index than with maximum pool depth (44.4% vs 15.1%; odds ratio = 4.5, 99% CI = 1.6-12.8).
                The results suggest that after 42 weeks fetal monitoring with the modified biophysical profile does not improve pregnancy outcome as measured by umbilical cord pH, but is more likely to yield an abnormal result. The higher incidence of abnormal monitoring results in the modified biophysical profile group was likely to be caused by different methods of amniotic fluid assessment in the modified biophysical profile group (amniotic fluid index) and simple monitoring group (maximum pool depth). The use of amniotic fluid index as a test of fetal wellbeing in prolonged pregnancy may lead to more obstetric interventions with, as yet, unclear impact on the perinatal outcome. The technique used to perform transabdominal chorionic villus sampling (CVS) is not standardized, but aspiration of villi is generally obtained by discontinuous vacuum created in a syringe, manually or by a hand-grip device. We evaluated the feasibility of a new method of performing CVS which employs a 4-mL Vacutainer connected to the needle, producing a continuous negative pressure.
                Two hundred pregnant women, whose gestational age ranged from 10 + 2 to 16 + 2 (mean, 12 + 1) weeks, entered the randomized study, which was powered to detect with 90% probability the absence of any difference in the size of chorionic samples obtained by using a 20-mL syringe with the vacuum obtained by a hand-grip device (Group 1) or by a vacutainer (Group 2). Four operators with different levels of experience performed all the procedures, which were done transabdominally using a freehand technique with a 20-gauge needle under ultrasound guidance.
                Maternal age, body mass index, gestational age and the way the needle was inserted within the chorion were similar in the two groups. The median amount of villi sampled was 20 mg, with no differences between the two groups. The rate of fetal loss was 1.7%. All losses occurred in women of Group 1 who had only one needle insertion. A second needle insertion was required more frequently while using the vacutainer.
                This new technique for performing transabdominal CVS uses a readily available device and is as effective as traditional sampling systems to aspirate villi. It has the advantage of being a one-operator procedure. To estimate the effectiveness of intrapartum fetal monitoring by cardiotocography plus ST analysis using a strict protocol for performance of fetal blood sampling.
                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.
                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.
                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.
                I. In a prospective clinical randomized investigation 487 women had the condition of the fetus during labour supervised by means of stethoscope (AUS), while 482 women went through labour under surveillance of electronic fetal monitoring, cardiotocography (EFM). 349 women refused to participate in the investigation (NAI) and had delivery conducted according to the normal procedures of the department (70% AUS, 30% EFM). Significantly more pathological fetal heart rate patterns (FHR) were found in the EFM group compared to the AUS group in both the first and the second stage of labour. As a result significantly more vacuum extractions were performed in the EFM group than in the AUS group, while no statistical difference was found between the groups in the incidence of acute cesarean sections carried out for asphyxia. One case of intrapartum death occurred in the AUS group. No differences were found in Apgar scores after 1 and 5 min or in neonatal morbidity at examination on the 2nd and 5th days after delivery. A tendency towards more biochemically compromised children was found in the AUS group. The specificity for both methods was found to be acceptably high (80%), while the predictive value for both methods was low (50%). More research is therefore urgently needed to evaluate supplementary investigations and parameters for the evaluation of the intrapartum fetal condition. Intrapartum electronic fetal heart rate (FHR) monitoring and fetal blood gas sampling were compared with periodic auscultation of FHR in a multicentered randomized trial of preterm singleton pregnancies with fetal weights of 700-1750 g. Two hundred forty-six pregnancies were studied (electronic FHR monitoring N = 122, auscultation N = 124). Perinatal or infant death was associated with 14% of pregnancies with electronic FHR monitoring and 15% with auscultation. No significant differences were noted in the prevalence of low five-minute Apgar scores, intrapartum acidosis, intracranial hemorrhage, or frequency of cesarean section (P greater than .10). Compared with electronic FHR monitoring, intrapartum auscultation as done in this study is unlikely to be associated with detectable differences in perinatal outcomes within the high-risk setting of preterm labor.
When further testing to assess fetal well-being in labour is indicated, fetal scalp blood lactate estimation is more likely to be successfully undertaken than pH estimation. Action cut-off lactate values need to consider the lactate meter used. Further studies may consider sub-group analysis by gestational age, the stage of labour and sampling within a prolonged second stage of labour. Additionally, future studies may address longer-term neonatal outcomes, maternal satisfaction with intrapartum fetal monitoring and an economic analysis.