Electronic Fetal Heart Rate Monitoring Research Articles

Central Fetal Monitoring: Effect on Perinatal Outcomes and Cesarean Section Rate

Continuous electronic fetal heart monitoring during labor is routine in the United States—it presently is used in more than 85% of births. Nevertheless, benefit has not been unequivocally demonstrated, and some practitioners believe that the procedure may in fact increase the rate of operative delivery for fetal stress. Today many hospitals are incorporating central fetal monitoring into their labor and delivery suites. This retrospective study was planned to show whether central fetal monitoring influences neonatal outcomes and cesarean section rates. Central monitoring was utilized in 3512 deliveries and was not used in 3007 others. Outcome measures included the rate of cesarean section, 5-minute Apgar scores less than 7, and admission to the neonatal intensive care unit (NICU). The two groups of parturients were well matched for maternal age, body mass index, and birth weight at delivery. The only significant demographic difference between the groups was that there were 5% more white gravidas in the central monitoring group than in the group that was not monitored centrally. The cesarean section rate was the same with and without central fetal monitoring in term deliveries (13.4% and 14.5%, respectively) and in preterm deliveries (21.3% each). Similarly, there were no significant differences in the number of low Apgar scores (<7 at 5 minutes) in either term or preterm deliveries with and without central fetal monitoring. Finally, there was no difference in the rate of admission to the NICU for either term or preterm deliveries related to whether or not central fetal monitoring was carried out. Comparable results were obtained for all three outcomes when the data for term and preterm deliveries were pooled. Central fetal monitoring did not prevent perinatal morbidity in either term or preterm births in this retrospective survey. Because the procedure is very costly both to set up and to maintain, the apparent lack of benefit raises the question of whether available health care resources should be allocated for this purpose.

Modern intrapartum fetal monitoring: room for improvement?

Electronic fetal heart monitoring is the standard of care for intrapartum surveillance of the fetus. Despite its widespread use and general acceptance, data regarding the clinical beneWt in terms of fetal morbidity and mortality are controversial. While early trials could not demonstrate a beneWt from intrapartum monitoring [1, 2], a recent systematic review and meta analysis published by the Cochrane Collaboration clariWes that electronic fetal heart rate monitoring by cardiotocography does not reduce fetal mortality, but reduces neonatal seizures by 50%. Based on 22 randomized trials, continuous cardiotocography showed no signiWcant diVerence in the overall perinatal death rate compared to intermittent auscultation [relative risk (RR) 0.85, 95% conWdence interval (CI) 0.59–1.23, n = 33,513, 11 trials], but was associated with a halving of neonatal seizures (RR 0.50, 95% CI 0.31–0.80, n = 32,386, 9 trials). Cardiotocography had no signiWcant impact on the rates of cerebral palsy (RR 1.74, 95% CI 0.97–3.11, n = 13,252, 2 trials) [3]. Therefore, it is clear that electronic fetal heart rate monitoring is a valuable instrument for improving fetal morbidity. It comes, however, at a high price for the mother, because it signiWcantly increases the risk of cesarean section (RR 1.66, 95% CI 1.30–2.13, n = 18,761, 10 trials) as well as vaginal operative delivery (RR 1.16, 95% CI 1.01–1.32, n = 18,151, 9 trials) [3]. After the widespread acceptance of continuous electronic fetal heart rate monitoring, numerous interventions have been tested in an attempt to reduce the increased rate of operative deliveries while at the same time maintaining or improving fetal safety, among them fetal scalp blood sampling, fetal ST waveform analysis and fetal pulse oxymetry. Only fetal scalp blood sampling, however, has been implicated into clinical practice so far. Fetal scalp blood sampling and the subsequent assessment of fetal pH or lactate values is a promising method using equipment readily available in the labor ward. Despite its common use and interesting experimental data and correlations with perinatal fetal outcome, fetal scalp blood sampling has not been tested in randomized trials. Thus, there are no data allowing for an evidence-based recommendation of this method as an adjunct to non-reassuring fetal heart rate patterns on cardiotocography. Based on what we know today, fetal pulse oxymetry is not helpful in improving maternal or fetal outcomes. Bloom et al. [4] clearly demonstrated in a recent large randomized trial of 5,341 nulliparous women that fetal pulse oxymetry is not associated with a reduced rate of cesarean delivery or with an improvement in perinatal morbidity and mortality. This is in accordance with a previous Cochrane Collaboration review [5], making further trials of this diagnostic method seem unpromising. On the other hand, fetal ST waveform analysis has been shown to reduce the rate of cesarean section in two properly designed randomised trials [6, 7]. This technique uses electrocardiogram analysis of the ST C. Tempfer · L. HeXer · P. Husslein Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria

Uterine activity monitoring during labor

To summarize the currently available knowledge on (1) the methods to monitor uterine activity (UA); (2) the units to quantify UA; and (3) to assess the importance of abnormal contraction patterns on the condition of the fetus. The need for correct assessment and interpretation of the uterine contraction curve to improve fetal outcome will be emphasized. Correct assessment of the uterine contraction curve is an essential part of the cardiotocogram and should be obtained by the best method available; i.e., internal tocography (IT). IT provides objective information on quantization of UA and has the ability to obtain a good quality trace in an obese, restless patient. Accurate information on UA is essential because elevated UA during the first and second stage of labor can increase the risk of adverse fetal outcome. The relaxation time appears to be an important contraction parameter to maintain fetal well-being during labor. Almost all abnormal contraction patterns are characterized by shortening of the relaxation time and can lead to severe asphyxia. Duration, amplitude and frequency of contractions are of importance as well. The mean active pressure unit is the means to quantify UA since it incorporates these three contraction parameters. Proper application of UA monitoring by means of the internal method and adequate reading and interpretation of the uterine contraction curve is a prerequisite for high quality electronic fetal heart rate monitoring.

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Department of Obstetrics and Gynecology, Division of Maternal–Fetal Medicine, Johns Hopkins Hospital, Baltimore, Maryland

Evidence-informed obstetric practice during normal birth in China: trends and influences in four hospitals

BackgroundA variety of international organizations, professional groups and individuals are promoting evidence-informed obstetric care in China. We measured change in obstetric practice during vaginal delivery that could be attributed to the diffusion of evidence-based messages, and explored influences on practice change.MethodsSample surveys of women at postnatal discharge in three government hospitals in Shanghai and one in neighbouring Jiangsu province carried out in 1999, repeated in 2003, and compared. Main outcome measures were changes in obstetric practice and influences on provider behaviour. "Routine practice" was defined as more than 65% of vaginal births. Semi-structured interviews with doctors explored influences on practice.ResultsIn 1999, episiotomy was routine at all four hospitals; pubic shaving, rectal examination (to monitor labour) and electronic fetal heart monitoring were routine at three hospitals; and enema on admission was common at one hospital. In 2003, episiotomy rates remained high at all hospitals, and actually significantly increased at one; pubic shaving was less common at one hospital; one hospital stopped rectal examination for monitoring labour, and the one hospital where enemas were common stopped this practice. Mobility during labour increased in three hospitals. Continuous support was variable between hospitals at baseline and showed no change with the 2003 survey.Provider behaviour was mainly influenced by international best practice standards promoted by hospital directors, and national legislation about clinical practice.ConclusionObstetric practice became more evidence-informed in this selected group of hospitals in China. Change was not directly related to the promotion of evidence-based practice in the region. Hospital directors and national legislation seem to be particularly important influences on provider behaviour at the hospital level.

Obstetricians Still Await a Deus ex Machina

Intrapartum electronic fetal heart-rate monitoring was introduced with great enthusiasm in the early 1970s. Most cases of cerebral palsy were thought to result from asphyxia during the intrapartum period, and it was hoped that the ability to recognize intrapartum fetal asphyxia and intervene with a timely delivery would reduce the incidence of fetal neurologic injury. During the years after the adoption of electronic fetal monitoring, numerous publications documented associations between various fetal heart-rate patterns and short-term outcome measures of neonatal well-being. These outcome measures were assumed to be reliable surrogates for the development of long-term neurologic handicaps. By the end . . .

Intrapartum Electronic Fetal Heart Rate Monitoring and the Prevention of Perinatal Brain Injury

Electronic fetal heart rate monitoring (EFM) is the most widely used method of intrapartum surveillance, and our objective is to review its ability to prevent perinatal brain injury and death. Studies that quantified intrapartum EFM and its relation to specific neurologic outcomes (seizures, periventricular leukomalacia, cerebral palsy, death) were eligible for inclusion. MEDLINE was searched from 1966 to 2006 for studies that examined the relationship between intrapartum EFM and perinatal brain injury using these MeSH and text words: "cardiotocography," "electronic fetal monitoring," "intrapartum fetal heart rate monitoring," "intrapartum fetal monitoring," and "fetal heart rate monitoring." This search strategy identified 1,628 articles, and 41 were selected for further review. Articles were excluded for the following reasons: in case reports, letters, commentaries, and review articles, intrapartum EFM was not quantified, or specific perinatal neurologic morbidity was not measured. Three observational studies and a 2001 meta-analysis of 13 randomized controlled trials were selected for determination of the effect of intrapartum EFM on perinatal brain injury. Electronic fetal monitoring was introduced into widespread clinical practice in the late 1960s based on retrospective studies comparing its use to historical controls where auscultation was performed in a nonstandardized manner. Case-control studies have shown correlation of EFM abnormalities with umbilical artery base excess, but EFM was not able to identify cerebral white matter injury or cerebral palsy. Of 13 randomized controlled trials, one showed a significant decrease in perinatal mortality with EFM compared with auscultation. Meta-analysis of the randomized controlled trials comparing EFM with auscultation have found an increased incidence of cesarean delivery and decreased neonatal seizures but no effect on the incidence of cerebral palsy or perinatal death. Although intrapartum EFM abnormalities correlate with umbilical cord base excess and its use is associated with decreased neonatal seizures, it has no effect on perinatal mortality or pediatric neurologic morbidity.

Quantitative Kardiotokographie - wie sieht sie aus und was dürfen wir von ihr erwarten?

[corrected] Cardiotocography (CTG) seems to be a non-reliable, expensive but nevertheless practical method for fetal surveillance. Moreover, its diagnostic value is dependent on a long-standing experience of the obstetrician (midwife). It is difficult to define exact diagnostic criteria since nearly all CTG phenomena are lacking precise qualification by the naked eye. Therefore, the idea must be born in mind to analyze fetal heart frequency (FHF) by computer, first off-line then on-line, in order to evaluate its true diagnostic power objectively. The FHF of 583 deliveries terminated by the vaginal route were registered prospectively using a PC and an RS422 interface. In 443 cases acid-base measurements (ABL 500, RADIOMETER, Copenhagen) in blood of the umbilical artery (UA) and vein (UV) were available and plausible. In this study only the last 30 min ante-partum were analyzed. The program for FHF analysis was written in MATLAB (The Mathworks Inc., USA). A CTG score was developed using three components of FHF: basal FHF, the deceleration area of all dips, and the micro-fluctuation (MF) of the basal fetal heart rate (FHR). MF denotes the true number of "turning-points" per minute of basal FHR. For each component a maximum of 6 scoring points could be assigned according to empirical cut-off values. These cut-off values were determined using correlation analysis with acid-base parameters in UA blood, especially the actual pH. The accordance between score and pH values was further demonstrated by assignment of 0.036 pH-units to each of the 19 (18 + zero) scoring points, thus covering a pH range between 6.700 and 7.350 (UA). A resulting variable, delta pH (pH measured, UA-pH assigned) was studied and used for further analysis. In order to define criteria for fetal mortality in utero only cases with pH, UA between 7.250 and 7.350 were accepted. Median basal FHF under normal conditions amounted to 138 bpm (mean: 137 +/- 14.9) in 4180 minutes of 372 fetuses. 120 bpm equals the 13.4(th) and 160 bpm the 94.6(th) centile of the distribution. Given fetal normacidity (UA) MF is 58/minute and the mean MF 57.9 +/- 13.4, respectively, with a 10 (th) centile of 41/minute. MF and basal FHF are correlated significantly (r = 0.410, P << 10(-4)). The declaration-area per fetus is significantly correlated with actual pH (UA), r = -0.473, P << 10(-4). the score itself is highly significantly correlated with actual pH (UA) (r = -0.559, P << 10(-4)) and the other parameters of fetal acid-base balance. Nevertheless, prediction variability for pH, especially in score = 1, 2 and zero (minimal CTG pathology) is still present: 80% of all predicted pH values lie in between -0.092 and + 0.071. It is strongly suggested that this score-related predictive pH variability is caused by maternal breathing habits during the last 30 minutes of delivery. Adequate quantification of only three variables of FHR using a score leads to fairly good correlations with parameters of the fetal acid-base balance. Thus actual pH (UA) can be predicted in reasonable clinical limits. Still present variability in prediction of pH seems to be, in part, of maternal origin. The maternal influence could be eliminated by continuous (transcutaneous) monitoring of maternal pCO(2). Along these lines the quantitative electronic monitoring of FHR will be realized and instrumented (off-line and on-line) by nexus/gmt, Frankfurt, a.M., Germany.

Acute centralization of blood flow in compromised human fetuses evoked by uterine contractions

Background During fetal hypoxia blood is redistributed to the brain (‘brain-sparing’). Sequential changes of the cerebral and placental circulation in parallel in comparisons between basal conditions and acute hypoxic stress have not yet been thoroughly studied in human fetuses. Aim To explore acute fetal middle cerebral artery (MCA) circulatory changes relative to umbilical artery (UA) blood flow in a clinical experimental model with hypoxic stress provoked by uterine contractions during an oxytocin challenge test (OCT). Study design Prospective comparative between imminently compromised (OCT positive) and un-compromised (OCT negative) fetuses. Subjects and methods 82 term pregnancies suspected of intrauterine growth restriction were exposed to simultaneous electronic fetal heart rate monitoring and Doppler recordings of pulsatility index (PI) in the UA and MCA during basal conditions and during uterine contractions and relaxations at an OCT. Outcome measures Sequential changes of UA and MCA PI, OCT positive vs. negative cases. Nonparametric statistics with a P < 0.05 considered significant. Results The UA PI was significantly higher in OCT positive cases ( N = 10) compared with OCT negative cases ( N = 72) during uterine contractions and relaxations, but not during basal measurements. During contractions and relaxations the MCA PI decreased significantly in both groups (brain-sparing), but significantly more in OCT positive cases. Conclusions During acute hypoxic stress, changes towards a centralization of blood flow to the brain develop in imminently compromised (OCT positive) fetuses at an expense of the umbilicoplacental blood flow, and the brain-sparing flow is more pronounced than in un-compromised (OCT negative) fetuses.

Practices and views on fetal heart monitoring: a structured observation and interview study

To assess and explain deviations from recommended practice in National Institute for Clinical Excellence (NICE) guidelines in relation to fetal heart monitoring. Qualitative study. Large teaching hospital in the UK. Sixty-six hours of observation of 25 labours and interviews with 20 midwives of varying grades. Structured observations of labour and semistructured interviews with midwives. Interviews were undertaken using a prompt guide, audiotaped, and transcribed verbatim. Analysis was based on the constant comparative method, assisted by QSR N5 software. Deviations from recommended practice in relation to fetal monitoring and insights into why these occur. All babies involved in the study were safely delivered, but 243 deviations from recommended practice in relation to NICE guidelines on fetal monitoring were identified, with the majority (80%) of these occurring in relation to documentation. Other deviations from recommended practice included indications for use of electronic fetal heart monitoring and conduct of fetal heart monitoring. There is evidence of difficulties with availability and maintenance of equipment, and some deficits in staff knowledge and skill. Differing orientations towards fetal monitoring were reported by midwives, which were likely to have impacts on practice. The initiation, management, and interpretation of fetal heart monitoring is complex and distributed across time, space, and professional boundaries, and practices in relation to fetal heart monitoring need to be understood within an organisational and social context. Some deviations from best practice guidelines may be rectified through straightforward interventions including improved systems for managing equipment and training. Other deviations from recommended practice need to be understood as the outcomes of complex processes that are likely to defy easy resolution.

Fetal Pulse Oximetry Does Not Alter the Rate of Cesarean Delivery

The introduction of intrapartum fetal heart-rate monitoring in the 1970s was believed to herald an era in which hypoxia during labor would become nonexistent. Three decades later, electronic fetal heart-rate monitoring has contributed to an increase in the rate of cesarean delivery, but there is …

Toward Quantitative Fetal Heart Rate Monitoring

Continuous electronic fetal heart rate (FHR) monitoring during labor is motivated by the clinical experience that fetal distress causes loss of FHR variation and the occurrence of decelerations late during uterine contraction. This practice is of uncertain clinical benefit, perhaps because the interpretation is qualitative. We have developed new quantitative measures and analyzed cardiotocograph records from 148 consecutive patients, 44 of whom had at least one "nonreassuring" epoch. In multivariate regression models, measures of deceleration and variability were significantly associated with the obstetrician's diagnosis (receiver operating characteristic area 0.84, p < 0.05). This approach may be useful clinically.

Restrained cerebral hyperperfusion in response to superimposed acute hypoxemia in growth-restricted human fetuses with established brain-sparing blood flow

Objective To investigate the cerebral circulatory response to superimposed acute hypoxemia in growth-restricted fetuses with established brain-sparing flow (BSF) during basal conditions. Material and methods 76 term fetuses suspected of growth restriction were exposed to Doppler velocimetry in the umbilical artery (UA) and middle cerebral artery (MCA), and in 38–39 cases also in Galen's vein (GV), straight sinus (SS), and transverse sinus (TS), before and during an oxytocin challenge test (OCT), and simultaneous to electronic fetal heart rate monitoring. Nonparametric statistical analyses compared presence/absence of established BSF (MCA-to-UA pulsatility index [PI] ratio < 1.08) with a two-tailed P < 0.05 considered significant. Results The OCT (positive/negative) was not different in the BSF group (BSFG, N = 16) and the normal flow group (NFG, N = 60) ( P = 0.2). During uterine contractions, the MCA PI decreased in the NFG, but not in the BSFG. De novo GV pulsations and increase of GV maximum flow velocity occurred during contractions in the NFG, but not in the BSFG. Significant SS flow velocity waveform changes were found in neither group and TS flow changes in the BSFG only. Conclusions Fetuses without established brain-sparing flow during basal conditions responded with both arterial and venous brain-sparing flow during acute hypoxemia, whereas in fetuses with established brain-sparing flow the cerebral circulatory responses were absent or equivocal. Fetuses with established brain-sparing flow may have a limited capacity of further cerebral hyperperfusion during superimposed acute hypoxic stress.

Midwives’ visual interpretation of intrapartum cardiotocographs: intra‐ and inter‐observer agreement

This paper reports an examination of intra- and inter-observer agreement in midwives' visual interpretation of intrapartum cardiotocographs (CTGs). The issue of intra- and inter-observer agreement in the interpretation of CTG interpretation has serious implications for the validity of electronic fetal heart rate monitoring and subsequent decisions on intrapartum management. However, no studies were found that assessed intra- and inter-observer agreement in midwives' interpretations of CTG tracings. Twenty-eight midwives independently interpreted three intrapartum CTG tracings on two separate occasions using a self-administered Cardiotocograph Interpretation Skills Test. Inter-rater agreement in interpretation was assessed by cross-tabulating the two sets of raw data obtained at time 1 and time 2 and computing Cohen's Kappa (kappa). Intra-rater agreement was assessed by computing kappa for each rater with the two sets of raw data (time 1 and time 2) obtained from each individual. The data were collected in 2000. Overall intra-rater agreement ranged from 'fair to good' (kappa = 0.48) to 'excellent' (kappa = 0.92). Raters' classifications altered in 18% (n = 5) of cases for the normal tracing, in 29% (n = 8) for the suspicious tracing and in 11% (n = 3) for the pathological tracing. Inter-rater agreement was fair to good, with kappa statistics ranging from 0.65 to 0.74, respectively. Agreement was highest in the classification of decelerations (kappa = 0.79) and lowest in the assessment of baseline variability (kappa = 0.50). Overall inter-rater agreement was highest in the suspicious tracing (kappa = 0.77, excellent) and lowest in the normal tracing (kappa = 0.54, fair to good). Inter- and intra-observer variability are intrinsic characteristics of the interpretation of intrapartum CTGs. Levels of agreement revealed degrees of variation that expose room for improvement. Efforts are needed to reduce inter- and intra-observer variation in interpretation of intrapartum CTG tracings. In addition, research should focus on the development and evaluation of non-invasive, low observer variability methods of intrapartum assessment of fetal well-being. The subjectivity of CTG interpretation and inconsistencies in interpretation should also be considered in intrapartum management, clinical audit and in medico-legal settings.

Use of fetal pulse oximetry among high-risk women in labor: A randomized clinical trial

The purpose of this study was to determine the clinical role of fetal pulse oximetry to reduce cesarean delivery for a nonreassuring fetal heart rate tracing. Singletons > or =28 weeks were randomized to fetal pulse oximetry plus electronic fetal heart rate monitoring (monitoring + fetal pulse oximetry) or monitoring alone. Overall, 360 women in labor were recruited: 150 cases with monitoring+fetal pulse oximetry and 177 cases with monitoring alone were analyzed. Most demographic, obstetric, and neonatal characteristics were similar. Specifically, the gestational age, cervical dilation, and station of the fetal head were not differential factors. In addition, cesarean delivery for nonreassuring fetal heart rate tracing was not different between the group with monitoring+fetal pulse oximetry (29%) and the group with monitoring alone (32%; relative risk, 0.95; 95% CI, 0.75, 1.22). Likewise, cesarean delivery for arrest disorder was similar between the group with monitoring+fetal pulse oximetry (22%) and the group with monitoring alone (23%; relative risk, 1.05; 95% CI, 0.79, 1.44). However, the decision-to-incision time was shorter for the group with monitoring+fetal pulse oximetry (17.8 +/- 8.2 min) than for the group with monitoring alone (27.7 +/- 13.9 min; P < .0001). The use of fetal pulse oximetry with electronic fetal heart rate monitoring does not decrease the rate of cesarean delivery, although it does alter the decision-to-incision time.

A review of intrapartum fetal deaths, 1982 to 2002

This study identifies cases of unexpected intrapartum fetal deaths over 20 years in a Canadian tertiary hospital. Of 121,659 births, 82 were intrapartum deaths. Eleven fetuses were considered viable and nonanomalous. Six deaths were deemed ideally preventable. Application of electronic fetal heart rate monitoring and rapid operative delivery may reduce the already low rate of intrapartum fetal deaths.

Intrapartum fetal heart rate monitoring

The risk of fetal hypoxia during labour and delivery is far higher than in a similar period in the third trimester of pregnancy. Especially during the second stage of labour the fetus has an increased risk of suffering from hypoxia/asphyxia/acidosis. Particularly the development of neonatal seizures in the first 1–2 days following birth is an unfavourable sign for functioning in later life. Absence of accelerations and minimal or absent variability are prominent signs in infants who develop acidosis, followed by seizures in the neonatal period. A number of societies have provided guidelines on who, when and how to monitor the condition of the fetus during the process of labour and delivery. The choice mostly is between intermittent auscultation and electronic FHR monitoring. In some guidelines, electronic FHR monitoring is not a required standard, even for high-risk patients. Nevertheless few practitioners or hospitals have removed cardiotocographs from their labour and delivery units. The recommendation to leave the choice between intermittent auscultation and electronic FHR monitoring to the labouring woman and her attending clinician is based on the conclusions from meta-analyses summarizing outcomes and interventions in randomized controlled trials. Most randomized controlled trials (RCTs) were performed during the 1970s and 1980s. They comprise a mixture of low- and high-risk patients, and preterm and term labours. The studies lack information on how electronic FHR monitoring was performed. Allocation to either intermittent auscultation or electronic FHR monitoring has been variable. The outcome parameters varied likewise. Nearly all RCTs would not fulfil current standards for the quality of a randomised controlled trial. It is a general belief that the FHR tracings obtained with the external mode of FHR monitoring are of a quality comparable to the internal mode. Rupture of the membranes is considered unnecessary to generate a good quality trace. These opinions leading to false trust and the neglect of obtaining good quality traces are not supported by data from our own hospital. In singletons and especially in twins, internal FHR monitoring provides far better data than the external mode.

Intrapartum management of nonreassuring fetal heart rate patterns: A randomized controlled trial of fetal pulse oximetry

Objective 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). Results 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. Conclusion 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.