Fetal scalp stimulation (FSS) versus fetal blood sampling (FBS) for women with abnormal fetal heart rate monitoring in labor: a prospective cohort study

Determination of Foetal Scalp Blood Sampling pH as an Indicator of Loss of Foetal Well-Being in Women Undergoing Caesarean Section

Asphyxia during birth is one of the three leading causes of neonatal morbidity and mortality among newborns carried to term. The objective of this study was to evaluate the measurement of the foetal scalp blood pH as a measure of foetal status, evaluating: cord gases, meconium-stained fluid, APGAR score or the need for neonatal resuscitation in pregnant women undergoing caesarean sections. A cross-sectional study was carried out over a period of 5 years (2017-2021) at the Hospital de Poniente (southern Spain). A total of 127 pregnant women participated from whom a foetal scalp blood pH sample was taken and used to indicate the need for an urgent caesarean section. The results showed a correlation between the pH of the scalp blood and the pH of the umbilical cord artery, umbilical cord vein (Rho of Spearman arterial pH: 0.64, p < 0.001; Rho of Spearman venous pH: 0.58, p < 0.001) and the APGAR test one minute after delivery (Spearman's Rho coefficient of 0.33, p < 0.01). These results suggest that the foetal scalp pH should not be considered a foolproof method to indicate an urgent caesarean section. Foetal scalp pH sampling can be used as a complementary test, in conjunction with cardiotocography, to indicate whether an emergency caesarean section is necessary due to loss of foetal well-being.

Leadership Driven Persistent Reduction in Cesarean Trends: An Interventional Study for Quality Improvement

Background

This is a quality improvement study in North India undertaken to observe the efficacy and safety of a proposed set of interventions along Quality Improvement guidelines to reduce cesarean rates.

Materials and Methods

It was a retrospective cross-sectional study conducted in New Delhi. Measures were iteratively introduced from 2017 and improved using multiple PDSA (Plan, Do, Study, Act) cycles to note the overall reduction in cesarean rates. Chi square tests were done with subanalysis based on the Robsons classification.

Results

There was a significant reduction of annual cesarean rates from 36.35 to 22.87% over four years (p < 0.01) and in neonatal nursery admissions (p < 0.01). Covid outbreak saw a comparatively increased cesarean rate in 2020, for which it was excluded from the detailed study. The relative risk of cesarean delivery in the postintervention period was 0.62. Maximum reductions were seen in Robsons II, VI &VII.

Conclusion

Devising multipronged interventions and their implementation through PDSA cycles are essential. Such measures in moderate resources are replicable elsewhere as well.

Fetal scalp stimulation for assessing fetal well-being during labour

BACKGROUND

Continuous fetal heart rate monitoring by cardiotocography (CTG) is used in labour for women with complicated pregnancies. Fetal heart rate abnormalities are common and may result in the decision to expedite delivery by caesarean section. Fetal scalp stimulation (FSS) is a second-line test of fetal well-being that may provide reassurance that the labour can continue.

OBJECTIVES

To evaluate methods of FSS as second-line tests of intrapartum fetal well-being in cases of non-reassuring CTG. FSS and CTG were compared to CTG alone, and to CTG with fetal blood sampling (FBS).

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (which includes trials from CENTRAL, MEDLINE, Embase, CINAHL, the WHO ICTRP and conference proceedings), ClinicalTrials.gov (18 October 2022), and reference lists of retrieved studies.

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs) that compared any form of FSS to assess fetal well-being in labour. Quasi-RCTs, cluster-RCTs and studies published in abstract form were also eligible for inclusion, but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Two trials, involving 377 women, met the inclusion criteria for this review. Both trials were conducted in hospital settings and included women with singleton, term (37+0 weeks or more) pregnancies, a cephalic presentation, and abnormal CTG. Follow-up was until hospital discharge after the birth. A pilot trial of 50 women in a high-income country (Ireland) compared CTG and digital fetal scalp stimulation (dFSS) with CTG and fetal blood sampling (FBS). A single-centre trial of 327 women in a lower middle-income country (India) compared CTG and manual fetal stimulation (abdominal or vaginal scalp stimulation) with CTG alone. The two included studies were at moderate or unclear risk of bias. Both trials provided clear information on allocation concealment but it was not possible to blind participants or health professionals in relation to the intervention. Although objective outcome measures were reported, outcome assessment was not blinded or blinding was unclear. dFSS and CTG versus FBS and CTG There were no perinatal deaths and data were not reported for neurodevelopmental disability at >/= 12 months. The risk of caesarean section (CS) may be lower with dFSS compared to FBS (risk ratio (RR) 0.38, 95% confidence interval (CI) 0.16 to 0.92; 1 pilot trial, 50 women; very low-certainty evidence) but the evidence is very uncertain. There were no cases of neonatal encephalopathy reported. The evidence was also very uncertain between dFSS and FBS for assisted vaginal birth (RR 1.44, 95% CI 0.76 to 2.75; very low-certainty evidence) and for the spontaneous vaginal birth rate (RR 2.33, 95% CI 0.68 to 8.01, very low-certainty evidence). Maternal acceptability of the procedures was not reported. FSS and CTG versus CTG alone Manual stimulation of the fetus was performed either abdominally (92/164) or vaginally (72/164). There were no perinatal deaths and data were not reported for neurodevelopmental disability at >/= 12 months. There may be little differences in the risk of CS on comparing manual fetal stimulation and CTG with CTG alone (RR 0.83, 95% CI 0.59 to 1.18; 1 trial, 327 women; very low-certainty evidence), but again the evidence was very uncertain. There were no cases of neonatal encephalopathy reported. There may be no differences in the risk of assisted vaginal birth (RR 1.43, 95% CI 0.78 to 2.60; very low-certainty evidence) or in the rates of spontaneous vaginal birth (RR 1.01, 95% CI 0.85 to 1.21, very low-certainty evidence), but again the evidence is very uncertain. Maternal acceptability of abdominal stimulation/FSS was not reported although 13 women withdrew consent after randomisation due to concerns about fetal well-being.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence available which makes it unclear whether stimulating the fetal scalp is a safe and effective way to confirm fetal well-being in labour. Evidence was downgraded based on limitations in study design and imprecision. Further high-quality studies of adequate sample size are required to evaluate this research question. In order to be generalisable, these trials should be conducted in different settings, including broad clinical criteria at both preterm and term gestational ages, and standardising the method of stimulation. There is an ongoing study (FIRSST) that will be incorporated into this review in a subsequent update.

Digital fetal scalp stimulation (dFSS) versus fetal blood sampling (FBS) to assess fetal wellbeing in labour-a multi-centre randomised controlled trial: Fetal Intrapartum Randomised Scalp Stimulation Trial (FIRSST NCT05306756)

BACKGROUND

Cardiotocography (CTG) is a screening test used to detect fetal hypoxia in labour. It has a high false positive rate resulting in many potentially unnecessary caesarean sections. Fetal blood sampling (FBS) is a second-line test of the acid-base status of the fetus. It is used to provide either reassurance that it is safe for labour to continue or objective evidence of compromise so that delivery can be expedited. Digital fetal scalp stimulation (dFSS) to elicit a fetal heart rate acceleration is an alternative less invasive second-line test of fetal wellbeing. This study aims to provide robust evidence on the role of these two second-line tests in assessing fetal wellbeing and potentially preventing operative delivery.

METHODS

A multi-centre parallel group randomised controlled trial (RCT) is planned in four maternity centres in Ireland. The study aims to recruit 2500 nulliparous women with a term (≥37+0 weeks) singleton pregnancy who require a second-line test of fetal wellbeing in labour due to an abnormal CTG. Women will be allocated randomly to dFSS or FBS on a 1:1 ratio. The primary outcome is caesarean section. With 1250 women in each arm, the study will have 90% power to detect a difference of 5-6%, at a two-sided alpha significance level of 5%, assuming a caesarean section rate of at least 20% in the dFSS group.

DISCUSSION

If the proposed study shows evidence that dFSS is a safe, reliable and effective alternative to FBS, this would have ground-breaking implications for labour management worldwide. It could potentially lead to a reduction in invasive procedures and emergency caesarean sections.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05306756. Registered on 31 March 2022. The trial commenced enrolment on 10 May 2022. Ethical committee approval has been granted by the Research Ethics Committee (REC) of each hospital: Dublin/CWIUH REC: 12.06.2019; Cork/UCC REC: 29.11.2019; Galway/NUIG REC: 06.09.2019; Limerick/UL REC: 30.09.2019.

MANUAL FETAL STIMULATION DURING INTRAPARTUM FETAL SURVEILLANCE: A RANDOMISED CONTROLLED TRIAL: CharacteristicMaternal outcome

BACKGROUND

Manual fetal stimulation, either by mechanical manipulation or by stimulation of the fetal scalp is known to evoke a fetal heart response in a normal fetus.

OBJECTIVES

To assess the clinical effectiveness of manual fetal stimulation in assessment of fetal well-being during labor compared with no stimulation among women with a singleton pregnancy. To study the maternal and neonatal outcomes in the two groups.

STUDY DESIGN

A randomized controlled trial undertaken in the department of Obstetrics and Gynecology at a tertiary care teaching hospital between 2014 and 2016.

INCLUSION CRITERIA

Women with a singleton pregnancy at or after 37 weeks of gestation with cephalic presentation in labor having one of the following abnormalities on fetal heart tracing - fetal heart rate less than 110 beats per minute or more than 160 beats per minute, variable decelerations, late decelerations, minimal or absent beat to beat variability.

EXCLUSION CRITERIA

women requiring an immediate cesarean section; conditions which would preclude a vaginal delivery; intrauterine fetal demise or a major fetal congenital abnormality. The women were followed in labor and randomised to either the manual stimulation group or the no stimulation group when one of the CTG abnormalities were present. In the manual stimulation group the fetus was stimulated, abdominally by holding the head in the palm of one hand when the cervical dilatation was less than 3cm or vaginally by pinching the scalp of the fetus when the cervical dilatation was ≥3cm. After delivery, cord blood sample was collected and pH estimated. Mother and baby were followed up until discharge and mode of delivery, cord blood pH at birth, Apgar score at 1 and 5 minutes, neonatal intensive care unit admissions and duration of stay were the outcomes studied. Data was entered and compiled as frequency and percent for categorical variables. For continuous variables, data was calculated using mean and standard deviation. Chi-square test was used for assessing the association between the intervention and fetal and maternal outcomes.

RESULTS

A total of 327 women were included in the trial, of whom 164 were in the manual fetal stimulation group (group 1) and 163 were in the 'no stimulation' group (group 2). The Cesarean section rates were 25.61% in group 1 and 30.67% in group 2 (p=0.308). The mean cord blood pH at birth was 7.267±0.027 in group 1 and 7.265±0.024 in group 2 (p=0.479)and Apgar score at 1 min and 5 min (p=0.169 and p=0.423 respectively between the two groups) were not found to be statistically different among the two groups.

CONCLUSION

There is no significant change in feto-maternal outcomes with manual fetal stimulation in women having non-reassuring cardiotocographic changes in labor.

How to reduce fetal scalp blood sampling? A retrospective study evaluating the diagnostic value of scalp stimulation to predict fetal wellbeing assessed by scalp blood sampling

BACKGROUND

The Fetal Blood Sample (FBS) is used as an indicator of fetal acidosis during labor. Its place is discussed through the lack of randomized trials, as well as the limitations related to the technical procedure. An alternative could be the Fetal Scalp Stimulation (FSS).

AIM

Our objective was to describe the FSS diagnostic value to predict fetal wellbeing defined from FBS.

METHODS

The FSS consisted in a digital scalp stimulation for 15 s. Test was negative when an acceleration and/or a normal variability were elicited in the 2 min following. FSS was performed before each FBS which was classified as normal when pH was > 7.25. The diagnostic value was assessed by sensibility, specificity, positive and negative predictive values.

FINDINGS

148 women were included in our center from February to December 2019. Of the 191 FBS procedures, when accelerations were elicited sensibility was 58,3 (36.8-77.1), specificity was 67,5 (59.3-75), positive predictive value was 20,9 (12.5-32.9) and negative predictive value was 91.7 % (95 %CI, 85-95.5).

DISCUSSION

FBS is considered as the gold standard in our study which could be discussed as it is abandoned in some countries because of its questioned reliability and the lack of controlled randomized trials.

CONCLUSION

This study suggests that FSS could be an interesting alternative adjunctive test to perform in the first instance as it seems to be reliable, non-invasive and easy to perform in order to limit FBS only to absence of acceleration after FSS.

Earlier and improved screening for impending fetal compromise

OBJECTIVE

The use of pH and base excess (FSSPHBE) from fetal scalp sampling (FSS) was abandoned when cardiotocography (CTG) was believed to be sufficiently accurate to direct patient management. We sought to understand the fetus' tolerance to stress in the 1st stage of labor and to develop a better and earlier screening test for its risk for developing acidosis. To do so, we investigated sequential changes in fetal pH and BE obtained from FSS in the 1st stage of labor as part of a research protocol from the 1970s. We then examined the utility of multiple of the median (MoM's) conversion of BE and pH values, and the capacity of Fetal Reserve Index (FRI) scores to be a proxy for such changes. We then sought to examine the predictive capacity of 1st stage FRI and its change over the course of the first stage of labor for the subsequent development of acidosis risk in the 2nd stage of labor.

METHODS

Using a retrospective research database evaluation, we evaluated FSSPHBE data from 475 high-risk parturients monitored in labor and their neonates for 1 h postpartum. We categorized specimens according to cervical dilatation (CxD) at the time of FSSPHBE and developed non-parametric, multiples of the median (MOMs) assessments. FRI scores and their change over time were used as predictors of FSSPHBE. Our main outcome measures were the changes in BE and pH at different cervical dilatations (CxD) and acidosis risk in the early 2nd stage of labor.

RESULTS

FSSPHBE worsens over the course of the 1st stage. The implications of any given BE are very different depending upon CxD. At 9 cm, -8 Mmol/L is 1.1 MOM; at 3 cm, it would be 2.0 MOM. The FRI level and its trajectory provide a 1st stage screening tool for acidosis risk in the second stage.

CONCLUSIONS

Fetal acid-base balance ("reserve") deteriorates beginning early in the 1st stage of labor, irrespective of whether the fetus reaches a critical threshold of concern for actual acidosis. The use of MoM's logic improves appreciation of such information. The FRI and its trajectory reasonably approximate the trajectory of the FSSPHBE and appears to be a suitable screening test for early deterioration and for earlier interventions to keep the fetus out of trouble rather than wait until high risk status develops.

Effectiveness of fetal scalp stimulation test in assessing fetal wellbeing during labor, a retrospective cohort study

BACKGROUND

It is discussed whether fetal scalp stimulation (FSS) test is a reliable complimentary tool to cardiotocography (CTG) to assess fetal wellbeing during labor. The test is based on the assumption that a well-oxygenated fetus, in contrast to the depressed fetus, will respond to a certain stimulus. The aim of this study was to investigate the effectiveness of the FSS-test.

METHODS

A retrospective observational study carried out Copenhagen University Hospital, Herlev, Denmark. Laboring women with singleton pregnancies in cephalic presentation after gestation week 33 and indication for fetal blood sampling (FBS) were eligible for inclusion. The FSS-test was classified as positive when an acceleration was absent at the time of FBS and negative when an acceleration was present. Lactate in scalp blood was measured by the point-of-care device LactatePro™ and pH in artery umbilical cord blood by the stationary blood gas analyzer ABL800. Lactate level < 4.2 mmol/L in scalp blood and arterial cord pH > 7.1 were cut-offs for normality.

RESULTS

Three hundred eighty-five women were included. The cohort was divided by the FBS-to-delivery time: Group 1 (n = 128) ≤ 20 min, Group 2 (n = 117) 21-59 min and Group 3 (n = 140) ≥ 60 min. The proportion of FSS-positive tests differed significantly between the groups (p < 0.000). In Group 1 the sensitivity, specificity and likelihoods for scalp lactate ≥4.2 mmol/L were 81.5 (95% CI 67-90.1), 13.3 18.5 (95% CI 5.9-24.6), LHR+ 0.94 (95% CI 0.8-1.1) and LHR - 1.4 (95% CI 0.6-3.2) and for umbilical artery pH ≤ 7.10 the values were 82.6% (95% CI 61.2-95.1), 16% (95% CI 9.4-24.7), 1.0 (95% CI 0.8-1.2) and 1.1 (95% CI 0.4-3) respectively. Regardless of the FBS-to-delivery time the LHR+ for lactate ≥4.2 mmol/L increased to 1.38 (95% CI 1.2-1.6).

CONCLUSION

The effectiveness of scalp stimulation test was poor for both ruling in and out fetal hypoxia during labor. Absence of a provoked acceleration seems to be a normal phenomenon in the second stage of labor.

Comparing second-line tests to assess fetal wellbeing in Labor: a feasibility study and pilot randomized controlled trial

Objective: To explore the feasibility of conducting a randomized controlled trial (RCT) designed to compare the performance of digital fetal scalp stimulation (dFSS) and fetal blood sampling (FBS) as second-line tests of fetal wellbeing in Labor.Design: A feasibility study included 66 women who consented to both dFSS and FBS performed contemporaneously. A pilot randomized controlled trial included 50 women who were randomized to either dFSS or FBS.Setting: University-affiliated maternity hospital.Population: Women in Labor who required second-line testing of fetal well-being following abnormal fetal heart rate monitoring.Outcome measures: The primary outcome of interest was delivery by emergency cesarean section. Secondary outcomes included maternal and perinatal morbidity outcomes and procedural factors.Results: Of the 66 women recruited to the feasibility study 50 (76%) received the two interventions as per protocol. The demographic data indicated that future RCT should be limited to nulliparous women. After initial training and reminders, the dFSS procedure appeared to be acceptable to patients and clinicians and was interpreted appropriately. Recruitment of eligible women to the pilot RCT was successful (88%) with 50 of 63 eligible women randomized (79%) and no drop-outs. The cesarean section rate was high in both arms as expected with a cohort of women requiring second-line tests for abnormal fetal heart rate monitoring in Labor (5/25; 20% dFSS versus 13/25; 52% FBS, p = .018). Conservative estimates suggest that a sample size of 2500 randomized women would be required for a definitive RCT.Conclusions: This study suggests that dFSS, which has the potential to be a reliable alternative to FBS, could be evaluated in a well-designed randomized controlled trial.Trial registration: The definitive trial has been registered ISRCTN 13295826.

Evaluating the value of intrapartum fetal scalp blood sampling to predict adverse neonatal outcomes: A UK multicentre observational study

OBJECTIVE

To evaluate the value of fetal scalp blood sampling (FBS) as an adjunct test to cardiotocography, to predict adverse neonatal outcomes.

STUDY DESIGN

A multicentre service evaluation observational study in forty-four maternity units in the UK. We collected data retrospectively on pregnant women with singleton pregnancy who received FBS in labour using a standardised data collection tool. The primary outcome was prediction of neonatal acidaemia diagnosed as umbilical cord arterial pH < 7.05, the secondary outcomes were the prediction of Apgar scores<7 at 1st and 5th minutes and admission to the neonatal intensive care unit (NICU). We evaluated the correlation between the last FBS blood gas before birth and the umbilical cord blood and adjusted for time intervals. We constructed 2 × 2 tables to calculate the sensitivity, specificity, positive (PPV) and negative predictive value (NPV) and generated receiver operating curves to report on the Area Under the Curve (AUC).

RESULTS

In total, 1422 samples were included in the analysis; pH values showed no correlation (r = 0.001, p = 0.9) in samples obtained within an hour (n = 314), or within half an hour from birth (n = 115) (r=-0.003, p = 0.9). A suboptimal FBS pH value (<7.25) had a poor sensitivity (22%) and PPV (4.9%) to predict neonatal acidaemia with high specificity (87.3%) and NPV (97.4%). Similar performance was noted to predict Apgar scores <7 at 1st (sensitivity 14.5%, specificity 87.5%, PPV 23.4%, NPV 79.6%) and 5th minute (sensitivity 20.3%, specificity 87.4%, PPV 7.6%, NPV 95.6%), and admission to NICU (sensitivity 20.3%, specificity 87.5%, PPV 13.3%, NPV 92.1%). The AUC for FBS pH to predict neonatal acidaemia was 0.59 (95%CI 0.59-0.68, p = 0.3) with similar performance to predict Apgar scores<7 at 1st minute (AUC 0.55, 95%CI 0.51-0.59, p = 0.004), 5th minute (AUC 0.55, 95%CI 0.48-0.62, p = 0.13), and admission to NICU (AUC 0.58, 95%CI 0.52-0.64, p = 0.002). Forty-one neonates had acidaemia (2.8%, 41/1422) at birth. There was no significant correlation in pH values between the FBS and the umbilical cord blood in this subgroup adjusted for sampling time intervals (r = 0.03, p = 0.83).

CONCLUSIONS

As an adjunct tool to cardiotocography, FBS offered limited value to predict neonatal acidaemia, low Apgar Scores and admission to NICU.