Interventions for Intrauterine Resuscitation in Suspected Fetal Distress During Term Labor: A Systematic Review

Reconceptualizing Intrauterine Resuscitation and Its Short-Term Impact

Objective: Intrauterine resuscitation (IR) may be employed during labor to reduce emergency deliveries with concerns for fetal wellbeing emanating mostly from increased uterine contraction frequency and/or intensity. However, there is no standard definition of what constitutes IR, and how its impact is assessed. Here, we have created two measures of relative IR effectiveness, determined over a two-hour time frame after Pitocin was first initiated, and asked how fetal risk severity at the time of its initiation impacted IR effectiveness and the clinical decisions made. Methods: We analyzed 118 patients receiving Pitocin who underwent IR at least once during labor. Retrospectively, we assessed risk levels using our Fetal Reserve Index version 2 (FRI v2) scores that were calculated in 20 min timeframes. FRIv2 scores include various maternal, obstetric, and fetal risk factors, uterine contraction frequency, and FHR baseline rate, variability, accelerations, and decelerations. We define 3 IR scenarios to assess relative IR effectiveness. (1) No reduction in PIT infusion rates (PITSAME), (2) decreased PIT infusion rates (DPIT), or (3) PIT turned off (PIT OFF). Maternal repositioning and oxygen administration are nearly universal across all types and, therefore, are not considered in groupings. We then created two measures of IR effectiveness by classifying changes in FRI v2 scores over six 20 min windows coincident with and following IR use as (1) "Improvement" (improvement relative to the FRIv2 score at IR initiation) and (2) "Stabilization" (no further decrease in FRI score relative to the FRIv2 score in the sixth 20 min epoch after IR initiation). We evaluated the relative effectiveness of the three PIT options, and to test whether the level of fetal risk at the time of IR initiation affected its short-term effectiveness, FRI v2 risk scores were assigned to one of three groups (Green [1.00-0.625]; Yellow [0.50-0.25]; Red 0.25-0.0]). Higher scores indicate lower risk. Statistical analysis was performed with ANOVA and t- tests. Results: Overall, the first and/or the only initiation of IR resulted in improvement in 71% of cases and stabilization in 78% of cases. The remaining 22% were failures, meaning that the FRIv2 score in the 6th 20 min period was lower than the score at the time of initiation. There were modest, but not statistically significant, differences in effectiveness (improvement or stabilization) by type of IR. There was a trend toward lower IR effectiveness of PIT OFF during IR initiation when compared to PIT continuation or decreased groups. Conclusions: IR initiation or type did not vary significantly by retrospectively calculated levels of fetal risk, showing that wide variation in clinician practices, not necessarily correlated with what we believe actual risk was, determine how IR was used. The FRI provides contextualization of FHR elements by adding maternal, fetal, and obstetric risk factors, and increased uterine activity enables a more rigorous and reproducible approach to analysis of emerging fetal compromise and IR effectiveness. As practice has shifted from the over-aggressiveness of PIT use to now premature discontinuations with any tracing variation, we need better metrics. FRIv2 further improves its physiologic underpinnings. Thus, we propose a new approach to the overall assessment of IR practice.

Pathological fetal heart rate tracing patterns and neonatal outcomes among parturients beyond 32 weeks of gestation: a prospective observational study

PURPOSE

Distinct clinical phenotypes of pathological fetal heart rate (FHR) tracings may affect neonatal outcomes differently. This study aimed to determine and differentiate neonatal outcomes amongst the clinical phenotypes of pathological FHR tracing.

METHODS

This prospective observational study included women in labour with pathological fetal heart rate tracing during delivery. Pathological fetal heart rate tracings were characterized into 11 clinical phenotypes and corresponding neonatal and maternal outcomes were recorded. Neonates and mothers were followed till discharge from the hospital. The primary outcome was a 5-min Apgar score. The secondary outcomes were NICU admission, mode of delivery, mode of anesthesia, neonatal morbidity and mortality.

RESULT

271 women with pathological fetal heart rate tracing at the time of delivery were included in the study. Most of the women (64%) underwent cesarean delivery. The most common pathological fetal heart rate tracing was repetitive late decelerations (24.7%), followed by reduced variability with repetitive variable decelerations (24.4%). The 5-min Apgar score was comparable across all clinical phenotypes of pathological fetal heart rate tracing. Tachycardia with reduced variability was associated with a significantly higher likelihood of NICU admission (aOR 5.03, 95% CI 1.32-19.27, p = 0.018). Reduced variability, repetitive late decelerations and the combination of repetitive late decelerations with prolonged decelerations and reduced variability showed moderately increased odds of NICU admission.

CONCLUSIONS

The 5-min Apgar score remained comparable in all clinical phenotypes of pathological fetal heart rate tracing. Nonetheless, the odds of NICU admission were significantly higher in women with tachycardia and reduced variability.

Effect of maternal hyperoxygenation on neonatal outcomes among women in labour with pathological cardiotocography: an open-label randomized controlled trial

BACKGROUND

Hyperoxygenation has shown promise in improving suspicious fetal heart patterns in women in labor. However, the effect of hyperoxygenation on neonatal outcomes in women in labor with pathologic fetal heart rate tracing has not been studied.

OBJECTIVE

This study aimed to evaluate the effect of fractional inspiration of oxygen of 80% compared with fractional inspiration of oxygen of 40% on neonatal outcomes in women with pathologic fetal heart rate tracing.

STUDY DESIGN

This randomized, open-label, parallel arm, outcome assessor-blinded clinical trial was conducted in a large tertiary care university hospital. Singleton parturients aged ≥18 years at term gestation in active labor (cervical dilatation of ≥6 cm) with pathologic fetal heart rate tracing were recruited in the study. Pathologic fetal heart rate tracing was defined according to the International Federation of Gynecology and Obstetrics 2015 guidelines. The International Federation of Gynecology and Obstetrics classifies fetal heart rate tracings into 3 categories (normal, suspicious, and pathologic) based on rate, variability, and deceleration. Women in the intervention arm received oxygen at 10 L/min via a nonrebreathing mask, and those in the usual care arm received oxygen at 6 L/min with a simple face mask. Oxygen supplementation was continued until cord clamping. The primary outcome measure was a 5-minute Apgar score. The secondary outcome measures were the proportion of neonatal intensive care unit admission, umbilical cord blood gas variables, level of methyl malondialdehyde in the cord blood, and mode of delivery.

RESULTS

Overall, 148 women (74 women in the high fractional inspiration of oxygen arm and 74 in the low fractional inspiration of oxygen arm) with pathologic fetal heart rate tracing were analyzed. The demographic data, obstetrical profiles, and comorbidities were comparable. The median 5-minute Apgar scores were 9 (interquartile range, 8-10) in the hyperoxygenation arm and 9 (interquartile range, 8-10) in the usual care arm (P=.12). Furthermore, the rate of neonatal intensive care unit admission (9.5% vs 12.2%; P=.6) and the requirement of positive pressure ventilation (6.8% vs 8.1%; P=.75) were comparable. Concerning cord blood gas parameters, the hyperoxygenation arm had a significantly higher base deficit in the umbilical vein and lactate level in the umbilical artery. The cesarean delivery rate was significantly lower in women who received hyperoxygenation (4.1% [3/74]) than in women who received normal oxygen supplementation (25.7% [19/74]) (P=.00). In addition, umbilical vein malondialdehyde level in the umbilical vein was lower in the hyperoxygenation group (8.28±4.65 μmol/L) than in the normal oxygen supplementation group (13.44±8.34 μmol/L) (P=.00).

CONCLUSION

Hyperoxygenation did not improve the neonatal Apgar score in women with pathologic fetal heart rate tracing. In addition, neonatal intensive care unit admission rate and blood gas parameters remained comparable. Therefore, the results of this trial suggest that a high fractional inspiration of oxygen supplementation confers no benefit on neonatal outcomes in women with pathologic fetal heart rate tracings and normal oxygen saturation.

Association between gestational visit-to-visit blood pressure variability and adverse neonatal outcomes

The authors aimed to explore the association between visit‐to‐visit blood pressure variability (BPV) in pregnant women and adverse neonatal outcomes. The study included 52 891 pregnant women. BPV was calculated as standard deviation (SD) and coefficient of variation (CV) of systolic blood pressure (SBP) or diastolic blood pressure (DBP). All participants were divided into four groups by the quartiles of BPV. When comparing the highest quartiles to the lowest quartiles of DBP SD in all participants, the fully adjusted ORs were 1.19 (95% CI 1.11–1.27, p for trend < .001) for fetal distress, 1.32 (95% CI 1.14–1.54, p for trend < .001) for small for gestational age, 1.32 (95% CI 1.06–1.63, p for trend = .003) for 1‐min Apgar score ≤ 7. When comparing the highest quartiles to the lowest quartiles of DBP CV, ORs were 1.22 (95% CI 1.14–1.30, p for trend < .001) for fetal distress, 1.38 (95% CI 1.17–1.61, p for trend < .001) for small for gestational age, 1.43 (95% CI 1.14–1.79, p for trend < .001) for 1‐min Apgar score ≤ 7. ORs for preterm birth and 5‐min Apgar score ≤ 7 were not statistically significant. However, in participants with gestational hypertension or preeclampsia, ORs for preterm birth were 2.80 (95% CI 1.99–3.94, p for trend < .001) in DBP SD and 3.25 (95% CI 2.24–4.72, p for trend < .001) in DBP CV when extreme quartiles were compared. In conclusion, higher visit‐to‐visit BPV was associated with adverse neonatal outcomes.

Effects of maternal ritodrine hydrochloride administration on the heart rate of preterm fetal sheep with intraamniotic inflammation

Ritodrine hydrochloride is used for pregnancy prolongation and intrauterine fetal resuscitation. However, its clinical significance in intraamniotic inflammation during preterm labor and intrauterine fetal distress is unclear. We investigated the effects of maternal ritodrine hydrochloride administration (MRA; 200 μg/min for 2 h, followed by 800 μg/min for 2 h after 24 h) on fetal physiological parameters. For this purpose, we used chronically instrumented pregnant sheep at 113–119 d (term = 145 d) of gestation without (Group 1, n = 5) and with (Group 2, n = 5) intraamniotic inflammation induced by lipopolysaccharide injection into the amniotic cavity. The changes in fetal heart rate (FHR) and short-term variability (STV) and long-term variability (LTV) in FHR, fetal blood pressure, and fetal arterial blood gas (FABG) values were measured before and at 1 and 2 h after initiating MRA. Before MRA, all parameters were similar between Groups 1 and 2; however, there was significantly higher STV in Group 2 than in Group 1 before MRA at 800 μg/min, significantly higher partial arterial pressure of carbon dioxide in FABG in Group 2 than in Group 1 before MRA at 200 μg/min, and significantly lower blood glucose (BG) in Group 2 than in Group 1 before MRA at 800 μg/min. One hour after MRA, the FHR, STV, and LTV were significantly higher at 800 μg/min than those at the baseline in Group 1, as determined by the Friedman test; however, no significant difference was observed in Group 2. Additionally, the FABG pH significantly decreased 1 h after MRA at 800 μg/min in Group 2, whereas FABG lactate and BG significantly increased 2 h after MRA at 800 μg/min in Groups 1 and 2. Thus, short-term MRA at 800 μg/min increased the FHR, STV, and LTV significantly; these values were further modified under intraamniotic inflammation.

Effects of acute tocolysis using ritodrine hydrochloride on foetal heart rate patterns in intrauterine foetal resuscitation: a retrospective, single-centre observational study

No consistent recommendations concerning the preferred tocolytic agents for intrauterine foetal resuscitation are available. We evaluated the effects of acute tocolysis (AT) using ritodrine hydrochloride on foetal heart rate (FHR) patterns and neonatal outcomes. We retrospectively analysed the data of patients undergoing emergency caesarean section because of non-reassuring foetal status indicated by foetal scalp electrodes. Patients were classified into AT (ritodrine hydrochloride approximately 500 µg/min) and control groups with 15 and 12 participants, respectively. FHR patterns, Apgar scores, umbilical arterial analysis, and neonatal admission were compared. All participants had FHR category II; decelerations disappeared in all foetuses in the AT group, with no significant difference in neonatal outcomes. The AT group had a higher baseline FHR and lower short-term FHR variability than the control group, indicating foetal autonomic responses. Further studies are needed to clarify the effects of AT on FHR patterns, neonatal outcomes, and foetal and neonatal autonomic responses.Impact statementWhat is already known on this subject? The usefulness of acute tocolysis using ritodrine hydrochloride has been well-documented in several studies; however, such an application often induces side effects, such as maternal tachycardia, palpitations, and tremors.What the results of this study add? The short-term administration of ritodrine hydrochloride eliminated decelerations, with no significant difference in neonatal outcomes in pregnant women with foetal heart rate category II. Meanwhile, there were higher foetal heart rate and lower short-term foetal heart rate variability in pregnant women administered with ritodrine hydrochloride, indicating foetal autonomic responses.What the implications are of these findings for clinical practice and/or further research? Ritodrine hydrochloride administration, even for short-term, appears to be associated with foetal autonomic responses. Further studies with stratification of patient groups based on the severity and aetiology of non-reassuring foetal status, including pregnant women with foetal category III, would elucidate the risk and benefit of acute tocolysis using ritodrine hydrochloride, based on foetal heart rate patterns, neonatal outcomes, and foetal and neonatal autonomic responses.

Health care workers' experiences of managing foetal distress and birth asphyxia at health facilities in Northern Uganda

BACKGROUND

Birth asphyxia is one of the leading causes of intrapartum stillbirth and neonatal mortality worldwide. We sought to explore the experiences of health care workers in managing foetal distress and birth asphyxia to gain an understanding of the challenges in a low-income setting.

METHODS

We conducted in-depth interviews with 12 midwives and 4 doctors working in maternity units from different health facilities in Northern Uganda in 2018. We used a semi-structured interview guide which included questions related to; health care workers' experiences of maternity care, care for foetal distress and birth asphyxia, views on possible preventive actions and perspectives of the community. Audio recorded interviews were transcribed verbatim and analysed using inductive content analysis.

RESULTS

Four categories emerged: (i) Understanding of and actions for foetal distress and birth asphyxia including knowledge, misconception and interventions; (ii) Challenges of managing foetal distress and birth asphyxia such as complexities of the referral system, refusal of referral, lack of equipment, and human resource problems, (iii) Expectations and blame from the community, and finally (iv) Health care worker' insights into prevention of foetal distress and birth asphyxia.

CONCLUSION

Health care workers described management of foetal distress and birth asphyxia as complex and challenging. Thus, guidelines to manage foetal distress and birth asphyxia that are specifically tailored to the different levels of health facilities to ensure high quality of care and reduction of need for referral are called for. Innovative ways to operationalise transportation for referral and community dialogues could lead to improved birth experiences and outcomes.

A randomized controlled trial studying the effect of maternal hyperoxygenation on fetal heart rate in suspected fetal distress

OBJECTIVE

To investigate the effect of maternal hyperoxygenation on fetal heart rate (FHR) when applied for suspected fetal distress during the second stage of term labor.

APPROACH

A single-center randomized controlled trial was conducted in a tertiary care hospital in The Netherlands. Participants were included during the second stage of labor in case of an intermediary or abnormal FHR pattern. Patients were randomized to receive either 100% oxygen at 10 l/min until delivery, or conventional care without additional oxygen. The primary outcome was the change in FHR pattern before and after the onset of the study, measured as the change in depth and duration of FHR decelerations. Secondary outcome measures were features based on phase-rectified signal averaging (PRSA), baseline assignability, and deceleration characteristics of the FHR pattern.

MAIN RESULTS

Between March 2016 and April 2018, 117 women were included. The FHR pattern could be analyzed for 71 participants, the other 46 women delivered before the end of the post time-frame. A 2.3% reduction in depth and duration of FHR decelerations was found after maternal hyperoxygenation, compared to a 10% increase in the control group (p = 0.24). Maternal hyperoxygenation had a significantly positive effect on PRSA metrics, with a decrease in PRSA-acceleration capacity (p = 0.03) and PRSA-deceleration capacity (p = 0.02) in the intervention group compared to the control group.

SIGNIFICANCE

The difference in depth and duration of decelerations after the start of the study was not significantly different between both study groups. A statistically significant positive effect on PRSA-deceleration capacity and PRSA-acceleration capacity was found after maternal hyperoxygenation, which might be associated with a positive effect on neonatal outcome.

Intrapartum fetal heart rate between 150 and 160 bpm at or after 40 weeks and labor outcome

INTRODUCTION

A baseline fetal heart rate between 110 and 160 bpm is considered normal. However, among normal fetuses the average baseline heart rate has been shown to diminish progressively and the 90th centile of the fetal heart rate at 40 weeks of gestation has been consistently found at around 150 bpm. The aim of our study was to assess the labor and neonatal outcome of fetuses at 40 gestational weeks or beyond, whose intrapartum baseline fetal heart rate was between 150 and 160 bpm.

MATERIAL AND METHODS

Retrospective cohort study including singleton pregnancies with spontaneous onset of labor, gestational age between 40⁺⁰ and 42⁺⁰ weeks, category I CTG trace according to the FIGO guidelines 2015 with baseline fetal heart rate between 110 and 160 bpm during the first 60 minutes of active labor. Exclusion criteria were maternal hyperpyrexia at admission, fetal arrhythmias, maternal tachycardia (>110 bpm) and uterine tachysystole (>5 contractions/10 minutes). The following outcomes were compared between fetuses with a baseline ranging between 110 and 149 bpm and those with a baseline ranging between 150 and 160 bpm: incidence of meconium-stained amniotic fluid, intrapartum hyperpyrexia, mode of delivery, Apgar at 5 minutes <7, arterial pH <7.1 and Neonatal Intensive Care Unit admission, incidence of a composite adverse neonatal outcome.

RESULTS

In all, 1004 CTG traces were included in the analysis, 860 in Group 110-149 bpm and 144 in Group 150-160 bpm. Group 150-160 bpm had a significantly higher incidence of meconium-stained amniotic fluid (odds ratio [OR] 2.6; 95% CI 1.8-3.8), maternal intrapartum hyperpyrexia (OR 4.7; 95% CI 1.1-14.6), urgent/emergent cesarean section for suspected fetal distress (OR 13.4; 95% CI 3.3-54.3), Apgar <7 at 5th min (OR 9.13; 95% CI 1.5-55.1) and neonatal acidemia (OR 3.5; 95% CI 1.5-55.1). Logistic regression including adjustiing for potential confounders showed that fetal heart rate between 150 and 160 bpm is an independent predictor of meconium-stained amniotic fluid (adjusted odds ratio [aOR] 2.2; 95% CI 1.5-3.3), cesarean section during labor for fetal distress (aOR 10.7; 95% CI 2.9-44.6), neonatal acidemia (aOR 2.6; 95% CI 1.1-6.7) and adverse composite neonatal outcome (aOR 2.6; 95% CI 1.2-5.6).

CONCLUSIONS

In fetuses at 40 weeks or beyond, an intrapartum fetal heart rate baseline ranging between 150 and 160 bpm seems associated with a higher incidence of labor complications.

The effect of intrauterine resuscitation by maternal hyperoxygenation on perinatal and maternal outcome: a randomized controlled trial

BACKGROUND

Maternal hyperoxygenation is widely used during labor as an intrauterine resuscitation technique. However, robust evidence regarding its beneficial effect and potential side effects is scarce, and previous studies show conflicting results.

OBJECTIVE

To assess the effect of maternal hyperoxygenation upon suspected fetal distress during the second stage of term labor on fetal heart rate, neonatal outcome, maternal side effects, and mode of delivery.

MATERIALS AND METHODS

In a single-center randomized controlled trial in a tertiary hospital in The Netherlands, participants were randomized in case of an intermediary or abnormal fetal heart rate pattern during the second stage of term labor, to receive either conventional care or 100% oxygen at 10 L/min until delivery. The primary outcome was the change in fetal heart rate pattern. Prespecified secondary outcomes were Apgar score, umbilical cord blood gas analysis, neonatal intensive care unit admission, perinatal death, free oxygen radical activity, maternal side effects, and mode of delivery. We performed subgroup analyses for intermediary and abnormal fetal heart rate, and for small for gestational age fetuses.

RESULTS

From March 2016 through April 2018, a total of 117 women were included. Fetal heart rate patterns could be analyzed in 71 women. Changes in fetal heart rate (defined as improvement, equal, or deterioration) in favor of maternal hyperoxygenation were significant (odds ratio, 5.7; 95% confidence interval, 1.7-19.1) using ordinal logistic regression. Apgar score, umbilical cord blood gas analysis, free oxygen radicals, and mode of delivery showed no significant differences between the intervention and control group. Among women with an abnormal fetal heart rate, there were fewer episiotomies on fetal indication in the intervention group (25%) than in the control group (65%, P < .01).

CONCLUSION

Maternal hyperoxygenation has a positive effect on the fetal heart rate in the presence of suspected fetal distress during the second stage of labor. There was no significant difference in the mode of delivery or neonatal outcome; however, significantly fewer episiotomies on fetal indication were performed following maternal hyperoxygenation in the subgroup with abnormal fetal heart rate pattern.

Intrauterine resuscitation during the second stage of term labour by maternal hyperoxygenation versus conventional care: study protocol for a randomised controlled trial (INTEREST O2)

BACKGROUND

Perinatal asphyxia is, even in developed countries, one the major causes of neonatal morbidity and mortality. Therefore, if foetal distress during labour is suspected, one should try to restore foetal oxygen levels or aim for immediate delivery. However, studies on the effect of intrauterine resuscitation during labour are scarce. We designed a randomised controlled trial to investigate the effect of maternal hyperoxygenation on the foetal condition. In this study, maternal hyperoxygenation is induced for the treatment of foetal distress during the second stage of term labour.

METHODS/DESIGN

This study is a single-centre randomised controlled trial being performed in a tertiary hospital in The Netherlands. From among cases of a suboptimal or abnormal foetal heart rate pattern during the second stage of term labour, a total of 116 patients will be randomised to the control group, where normal care is provided, or to the intervention group, where before normal care 100% oxygen is supplied to the mother by a non-rebreathing mask until delivery. The primary outcome is change in foetal heart rate pattern. Secondary outcomes are Apgar score, mode of delivery, admission to the neonatal intensive care unit and maternal side effects. In addition, blood gas values and malondialdehyde are determined in umbilical cord blood.

DISCUSSION

This study will be the first randomised controlled trial to investigate the effect of maternal hyperoxygenation for foetal distress during labour. This intervention should be recommended only as a treatment for intrapartum foetal distress, when improvement of the foetal condition is likely and outweighs maternal and neonatal side effects.

TRIAL REGISTRATION

EudraCT, 2015-001654-15; registered on 3 April 2015. Dutch Trial Register, NTR5461; registered on 20 October 2015.

Urgency of caesarean section, grading, alarm chain and intrauterine resuscitation - a survey of Scandinavian practice

BACKGROUND

About 40,000 women have caesarean section in Scandinavia each year. Organizational factors for emergency caesarean section (CS), classification, anaesthetic practice, alarm chain, intrauterine resuscitation has all been investigated in the United Kingdom, but no information from the Scandinavian countries exists.

METHODS

Using publicly available data from the National Board of Health, obstetric anaesthetic departments were identified. The heads of the departments provided e-mail contact details of two anaesthesiologists regularly practicing obstetric anaesthesia who were then surveyed.

RESULTS

One hundred and forty-five specialists from 82 departments in Scandinavia replied to our survey. Ninety-five percent of Danish specialists reported a three-grade classification system for urgency CS. Where classification in Denmark was enumerative classification, Norwegians equally reported enumerative and verbal descriptors, whereas Swedish specialists mostly reported verbal descriptors. Local guidelines describing decision-to-delivery interval for emergency CS was reported by 100% of Danish specialists vs. 47% from Norway and 85% from Sweden. Mean benchmark decision-to-delivery interval for emergency CS was 12.7 min. General anaesthesia for emergency CS was highly favoured in Norway (95%) and Sweden (97%), compared to Denmark (49%). Twenty specialists reported existence of local guidelines for intrauterine resuscitation.

CONCLUSION

Our survey of Scandinavian specialists indicate emergency CS practise differs from United Kingdom practices in several aspects; general anaesthesia is by the majority of Scandinavian specialists reported as the default choice for emergency CS and benchmark for decision-to-delivery interval is < 20 min. Nomenclature used for classification showed considerable variance in Norway and Sweden compared to Denmark. No joint Scandinavian guidelines exist.