Cesarean delivery for fetal distress: rate and risk factors

The "30-minute rule" for expedited delivery: fact or fiction?

Initially developed from hospital feasibility data from the 1980s, the "30-minute rule" has perpetuated the belief that the decision-to-incision time in an emergency cesarean delivery should be <30 minutes to preserve favorable neonatal outcomes. Through a review of the history, available data on delivery timing and associated outcomes, and consideration of feasibility across several hospital systems, the use and applicability of this "rule" are explored, and its reconsideration is called for. Moreover, we have advocated for balanced consideration of maternal safety with rapidity of delivery, encouraged process-based approaches, and proposed standardization of terminology regarding delivery urgency. Furthermore, a standardized 4-tier classification system for delivery urgency, from class I, for a perceived threat to maternal or fetal life, to class IV, a scheduled delivery, and a call for further research with a standardized structure to facilitate comparison have been proposed.

A Retrospective Review of Decision to Delivery Time Interval for Foetal Distress at a Central Hospital

Purpose

The aim of this study was to describe the trajectory of emergency caesarean deliveries for foetal distress at Chris Hani Baragwanath Academic Hospital (CHBAH).

Patients and Methods

A retrospective, contextual, descriptive study, using consecutive convenience sampling was done reviewing all the records of emergency caesarean deliveries for foetal distress at CHBAH in February 2019 until a minimum sample size of 385 was reached.

Results

During the study period, a total of 617 caesarean deliveries were done, of which 572 (92.7%) were emergencies. Foetal distress accounted for 395 (69.1%) of the emergency caesarean deliveries. No emergency caesarean delivery for foetal distress conformed to the 30-minute DDI and the mean (SD) DDI was 411 (291) minutes. The mean (SD) 5-minute and 10-minute Apgar scores were 8.4 (1.6) and 9.6 (1.3), respectively. There was a significant difference between the type of anaesthetic (general or neuraxial), with those receiving general anaesthesia having shorter anaesthetic start to cut time (p=0.0110). However, those delivered following neuraxial anaesthesia had better 5-minute (p=0.0002) and 10-minute (p=0.0175) Apgar scores.

Conclusion

This study showed that a DDI of 30-minutes, was not achieved at CHBAH during the study period. Most babies diagnosed with foetal distress pre-delivery had 5-minute and 10-minute Apgar scores inconsistent with this diagnosis. This over-diagnosis of foetal distress in some cases could have led to delays in delivery of babies who had actual foetal distress and where a 30-minute DDI could have improved outcome.

Prediction of non-reassuring fetal status and umbilical artery acidosis by the maternal characteristic and ultrasound prior to induction of labor

Objective

To investigate the predictive value of pre-induction digital examination, sonographic measurements and parity for the prediction of non-reassuring fetal status and cord arterial pH < 7.2 prior to the induction of labor (IOL).

Method

This was a prospective observational study, including 384 term pregnancies undergoing IOL. Before the IOL, the Bishop score (BS) by digital examination, sonographic Doppler parameters and the estimated fetal weight (EFW) was assessed. The fetal cord arterial was sampled to measure the pH at delivery. Multivariate logistic regression analysis was performed to identify independent predictors of non-reassuring fetal status and low cord arterial pH.

Results

Forty four cases (11.5%) had non-reassuring fetal status, and 76 cases (19.8%) had fetal cord arterial pH < 7.2. In the non-reassuring fetal status group, the incidence of cord arterial pH < 7.2 was significantly higher than that in the normal fetal heart rate group (χ² = 6.401, p = 0.011). Multivariate analysis indicated that significant independent predictors of non-reassuring fetal status were nulliparity (adjusted odds ratio [AOR]: 3.746, p = 0.003), EFW < 10^th percentile (AOR: 3.764, p = 0.003) and cerebroplacental ratio (CPR) < 10^th centile (AOR:4.755, p < 0.001). In the prediction of non-reassuring fetal status, the performance of the combination of nulliparity and EFW < 10th percentile was improved by the addition of CPR < 10th percentile (AUC: 0.681, (95%CI: 0.636 to 0.742) vs 0.756, (95%CI:0.713 to 0.795)), but the difference was not significant (DeLong test: z = 1.039, p = 0.053).. None of the above variables were predictors of cord arterial pH < 7.2.

Conclusion

The risk of fetal acidosis has increased in cases of non-reassuring fetal status. Nulliparity, small for gestational age and CPR < 10th centile are independent predictors for non-reassuring fetal status in term fetuses, though the addition of CPR < 10th centile could not significantly improve the screening accuracy.

Cesarean delivery at term for non-reassuring fetal heart rate tracing: risk factors and predictability

OBJECTIVE

To delineate risk factors for adverse outcomes among those who underwent cesarean delivery (CD) for non-reassuring fetal heart rate tracing (NRFHT) and ascertain whether neonatal or maternal morbidity can be predicted accurately.

METHODS

The Consortium on Safe Labor Database was utilized for this secondary analysis. Inclusion criteria were non-anomalous, singleton gestations between 37.0 and 41.6 weeks who underwent CD for NRFHT. Composite adverse neonatal outcomes (CANO) included Apgar <5 at 5 min, seizures, mechanical ventilation, sepsis, intraventricular hemorrhage, necrotizing enterocolitis or neonatal death. Composite adverse maternal outcomes (CAMO) included endometritis, blood transfusion, wound complication, admission to intensive care unit, thromboembolism, hysterectomy or death. Bivariable analysis and multivariable Poisson regression were used to identify risk factors independently associated with adverse outcomes. Receiver operating characteristic (ROC) curves were created to evaluate the predictive value of the models for adverse outcomes.

RESULTS

Of 228,438 births in the database, 7310 individuals (3.7%) met inclusion criteria. Among this cohort, CANO occurred 3.8% of the time. CANO was less common among people over 35 years (9.8% versus 18.4% p < .01) but was more common among those with at least high-school education (15.3% versus 11.2%; p < .01), varying by ethnicity (p < .01). CAMO occurred in 3.4% and was less common among those undergoing induction of labor (37.3% versus 49.4%; p < .01) and more common among those with clinical chorioamnionitis (8.4% versus 4.3%; p < .01). The area under the curve (AUC) for ROC curve to identify CANO was 0.63 implying a limited ability to predict neonatal adverse outcomes. The AUC for identifying women with maternal adverse outcomes was 0.69 also indicating a moderate prediction ability.

CONCLUSIONS

Among singletons between 37 and 41 weeks who labored, the rate of CD for NRFHT was about 3.7% and among them CANO occurred in 3.8%. While risk factors for adverse neonatal outcomes following CD for NRFHT are identifiable, they do not suffice to predict them.

Tocolysis and the risk of nonreassuring fetal status among pregnant women in labor: Findings from a population-based retrospective cohort study

The purpose of this study was to evaluate the association between tocolysis for preterm uterine contraction and the risk of nonreassuring fetal status.This was a retrospective cohort study using data from the Taiwan National Health Insurance Research Database. Pregnant women were enrolled if they delivered a baby during January 1, 2003 to December 31, 2011. The occurrence of the nonreassuring fetal status was compared between pregnant women with and without tocolytic treatment for preterm uterine contraction. Multivariable logistic regression models with adjusted cofounders were used to evaluate the association between tocolysis and the risk of nonreassuring fetal status.Of 24,133 pregnant women, 1115 (4.6%) received tocolytic treatment during pregnancy. After adjusting for covariates, pregnant women receiving tocolysis more than one time during pregnancy were found to have significantly higher risk of the nonreassuring fetal status when compared with pregnant women who did not receive tocolysis for uterine contraction (Odds Ratio = 2.70, 95% Confidence Interval: 1.13-6.49).Pregnant women with more frequent tocolysis for preterm uterine contraction during pregnancy had an increased risk of nonreassuring fetal status. Close evaluation of dose and duration of tocolytic treatment is necessary for pregnant women with preterm uterine contraction.

Maternal exposure to fine particulate matter and the risk of fetal distress

Prenatal life exposure to fine particulate matter (aerodynamic diameter less than or equal to 2.5 µm, PM_2.5) has been linked with increased risk of adverse fetal development and birth outcomes in previous studies. However, to our knowledge, no study has investigated the association of maternal PM_2.5 with the risk of fetal distress, which is a harmful fetal status and may lead to fetal brain damage, even fetal death. Therefore, we conducted a study to determine the association between maternal PM_2.5 and fetal distress among 7835 mother-infant pairs from a birth cohort, in Wuhan, China, 2013-2015. The individual daily PM_2.5 level was assessed using land use regression model. We evaluated the association of maternal PM_2.5 level over the whole pregnancy with fetal distress by logistic regression model, and estimated the risk between PM_2.5 exposure in specific trimester and fetal distress using generalized estimating equations. We observed that per 10 µg/m³ change of maternal PM_2.5 level over the whole pregnancy was associated with 25% increased risk of fetal distress (95% confidence interval: 1.09-1.44). Further, we found PM_2.5 level in the 2nd trimester, but not in the 1st and 3rd trimesters, was associated with fetal distress. Stratified analyses indicated that the association was only significant among infants who were born in cold seasons. Our study suggested that PM_2.5 exposure during the whole pregnancy exhibited significant associations with the risk of fetal distress, and exposure in the 2nd trimester maybe the susceptible window. Further stratified analyses indicated that birth season is a possible modifier in the association.

Continuous support during labour in childbirth: a Cross-Sectional study in a university teaching hospital in Shanghai, China

BACKGROUND

Fear or anxiety could result in adverse consequences on the course of labour. To date, family members are still not permitted in the delivery rooms in the majority of hospitals in China, and continuous support from hospital professional staff is also limited. This study aimed to evaluate the benefits of continuous support by family members and hospital professional staff during labour in China.

METHODS

In this Cross-Sectional study, 362 primiparous pregnancies who self-requested to receive continuous or one to one support with vaginal delivery and 362 primiparous pregnant women with routine hospital maternal care were included from a university teaching hospital. Data on the length of labour, postpartum haemorrhage (PPH), use of pain relief, use of oxytocin, fetal distress, emergency caesarean section and apgar score at 1 and 5 min were retrospectively collected from hospital medical data-base and compared between the two groups.

RESULTS

Multiple linear regressions adjusting for maternal age, BMI and birth weight, revealed the estimated length of labour for women with routine hospital maternal care was 2.03 times (95%CI 1.86 to 2.21) the duration of women with supportive care (median time, 3.05 h vs 1.5 h). In addition, Fisher's exact test showed the emergency caesarean section rate was significantly lower in women with supportive care compared to women with routine hospital maternal care (3.3% vs 24%).

CONCLUSION

Our results suggest that continuous support from family members together with hospital professional staff should be considered as part of intrapartum care in hospitals in China.

SLC9B1 methylation predicts fetal intolerance of labor

Fetal intolerance of labor is a common indication for delivery by Caesarean section. Diagnosis is based on the presence of category III fetal heart rate tracing, which is an abnormal heart tracing associated with increased likelihood of fetal hypoxia and metabolic acidemia. This study analyzed data from 177 unique women who, during their prenatal visits (7-15 weeks and/or 24-32 weeks) to Atlanta area prenatal care clinics, consented to provide blood samples for DNA methylation (HumanMethylation450 BeadChip) and gene expression (Human HT-12 v4 Expression BeadChip) analyses. We focused on 57 women aged 18-36 (mean 25.4), who had DNA methylation data available from their second prenatal visit. DNA methylation patterns at CpG sites across the genome were interrogated for associations with fetal intolerance of labor. Four CpG sites (P value <8.9 × 10^-9, FDR <0.05) in gene SLC9B1, a Na⁺/H⁺ exchanger, were associated with fetal intolerance of labor. DNA methylation and gene expression were negatively associated when examined longitudinally during pregnancy using a linear mixed-effects model. Positive predictive values of methylation of these four sites ranged from 0.80 to 0.89, while negative predictive values ranged from 0.91 to 0.92. The four CpG sites were also associated with fetal intolerance of labor in an independent cohort (the Johns Hopkins Prospective PPD cohort). Therefore, fetal intolerance of labor could be accurately predicted from maternal blood samples obtained between 24-32 weeks gestation. Fetal intolerance of labor may be accurately predicted from maternal blood samples obtained between 24-32 weeks gestation by assessing DNA methylation patterns of SLC9B1. The identification of pregnant women at elevated risk for fetal intolerance of labor may allow for the development of targeted treatments or management plans.

Decision-to-delivery interval in pregnant women with intrapartum non-reassuring fetal heart rate patterns

RATIONALE, AIMS AND OBJECTIVES

It has been proposed that delivery should be accomplished within 30 minutes after diagnosis of fetal distress. The objective of this study was to determine the decision-to-delivery interval (DDI) in emergency caesarean delivery for non-reassuring fetal heart rate (FHR).

METHODS

A total of 272 term, singleton pregnant women who underwent an emergency caesarean section for non-reassuring FHR were included. Patient characteristics and clinical data were reviewed. The timing of the decision-to-delivery process was reviewed.

RESULTS

The mean age was 28.7 years; the mean gestational age at delivery was 38.4 weeks; and 93.7% were in FHR category 2. The decision for emergency caesarean delivery was made during normal office hours in 31.6%. Median time for decision-to-operating room, decision-to-incision and decision-to-delivery was 42.3, 48.5 and 56 minutes, respectively. Only 6.6% of women had a DDI of <30 minutes, whereas 30.5% had a DDI of >75 minutes. Significantly shorter intervals were observed for every endpoint among patients in FHR category 3, and they were significantly more likely to deliver within 30 minutes than were those in FHR category 2 (41.2% vs. 4.3%, P < 0.001). Similar results were observed for cases that occurred during normal and after hours. Neonatal outcomes were comparable among different DDI categories.

CONCLUSION

Only 6.6% of women with non-reassuring FHR achieved the 30-minute goal for caesarean delivery (median 56 minutes). Better performance was observed among patients in FHR category 3 regardless of diagnosis time, with 41.2% of these patients having a DDI of <30 minutes.

Risk Factors for Neonatal Arterial Ischemic Stroke: The Importance of the Intrapartum Period

OBJECTIVE

To investigate risk factors for neonatal arterial ischemic stroke (NAIS), and compare them with those present in term controls and infants with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

Antepartum and intrapartum data were collected at presentation from 79 infants with NAIS and compared with 239 controls and 405 infants with HIE. The relationships between risk factors and NAIS were explored using univariable and multivariable regression.

RESULTS

Compared with controls, infants with NAIS more frequently had a family history of seizures/neurologic diseases, primiparous mothers, and male sex. Mothers of infants with NAIS experienced more intrapartum complications: prolonged rupture of membranes (21% vs 2%), fever (14% vs 3%), thick meconium (25% vs 7%), prolonged second stage (31% vs 13%), tight nuchal cord (15% vs 6%), and abnorm8al cardiotocography (67% vs 21%). Male sex (OR 2.8), family history of seizures (OR 6.5) or neurologic diseases (OR 4.9), and ≥1 (OR 5.8) and ≥2 (OR 21.8) intrapartum complications were independently associated with NAIS. Infants with NAIS and HIE experienced similar rates though different patterns of intrapartum complications. Maternal fever, prolonged rupture of membranes, prolonged second stage, tight nuchal cord, and failed ventouse delivery were more common in NAIS; thick meconium, sentinel events, and shoulder dystocia were more frequent in HIE. Abnormal cardiotocography occurred in 67% of NAIS and 77.5% of infants with HIE. One infant with NAIS and no infant with HIE was delivered by elective cesarean (10% of controls).

CONCLUSIONS

NAIS is multifactorial in origin and shares risk factors in common with HIE. Intrapartum events may play a more significant role in the pathogenesis of NAIS than previously recognized.

Evaluation of Clinical Diagnosis of Fetal Distress and Perinatal Outcome in a Low Resource Nigerian Setting

INTRODUCTION

Fetal distress has been shown to contribute to the increasing caesarean section rate. There has been controversy on the usefulness of clinical diagnosis of fetal distress using only the intermittent counting of the fetal heart rate and/or passage of meconium-stained liquor.

AIM

To evaluate the clinical diagnosis of fetal distress and the perinatal outcome.

MATERIALS AND METHODS

This was a retrospective study in which the case records of the patients, who were diagnosed of fetal distress at Federal Teaching Hospital, Abakaliki, Nigeria, from January 1, 2008 to December 31, 2014, were collated. The statistical analysis was done using the Statistical Package for Social Sciences version 17 software (SPSS Inc., Chicago IL, USA).

RESULTS

Out of the 15,640 deliveries carried out within the study period, 3,761 (24.05%) deliveries were through caesarean section. A total of 326 (8.9%) of the 3,761 caesarean sections were due to fetal distress within the study period. More so, a total of 227 (70.9%) babies were born with ≥ 7 Apgar score at the 1(st) minute of delivery. The perinatal mortality rate was 31.25 per 1000 deliveries. Though birth asphyxia was recorded more on babies of mothers that had fresh meconium-stained liquor and whose decision-intervention interval was more than 30 minutes when compared with those without any of the two conditions, there was no statistical significant difference between them.

CONCLUSION

The clinical diagnosis of fetal distress is accurate in 29.1% of the cases. However, it has led to an unnecessary caesarean section in the remaining 70.9% of the parturients. In order to reduce this high trend of unnecessary caesarean sections due to clinical diagnosis of fetal distress in this environment, antepartum fetal assessment with non-stress test or biophysical profile and intrapartum use of continuous electronic fetal monitoring should be used to confirm or refute the fetal distress before any surgical intervention. Fetal blood sampling and fetal pulse oximetry should be performed in event of non- re-assuring or abnormal cardiotocography.

Antepartum and intrapartum factors preceding neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

To determine whether antepartum factors alone, intrapartum factors alone, or both in combination, are associated with term neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

A total of 405 infants ≥ 35 weeks' gestation with early encephalopathy, born between 1992 and 2007, were compared with 239 neurologically normal infants born between 1996 and 1997. All cases met criteria for perinatal asphyxia, had neuroimaging findings consistent with acute hypoxia-ischemia, and had no evidence for a non-hypoxic-ischemic cause of their encephalopathy.

RESULTS

Both antepartum and intrapartum factors were associated with the development of HIE on univariate analysis. Case infants were more often delivered by emergency cesarean delivery (CD; 50% vs 11%, P < .001) and none was delivered by elective CD (vs 10% of controls). On logistic regression analysis only 1 antepartum factor (gestation ≥ 41 weeks) and 7 intrapartum factors (prolonged membrane rupture, abnormal cardiotocography, thick meconium, sentinel event, shoulder dystocia, tight nuchal cord, failed vacuum) remained independently associated with HIE (area under the curve 0.88; confidence interval 0.85-0.91; P < .001). Overall, 6.7% of cases and 43.5% of controls had only antepartum factors; 20% of cases and 5.8% of controls had only intrapartum factors; 69.5% of cases and 31% of controls had antepartum and intrapartum factors; and 3.7% of cases and 19.7% of controls had no identifiable risk factors (P < .001).

CONCLUSIONS

Our results do not support the hypothesis that HIE is attributable to antepartum factors alone, but they strongly point to the intrapartum period as the necessary factor in the development of this condition.

Heterogeneity of preterm birth subtypes in relation to neonatal death

OBJECTIVE

To investigate the heterogeneity of preterm labor, preterm premature rupture of membranes (PROM), and indicated preterm birth in overall and gestational-age-specific neonatal death risk.

METHODS

We used 2001 U.S. linked birth/infant death (birth cohort) data sets for this analysis. We categorized three preterm birth subtypes according to reported preterm PROM, induction of labor, cesarean delivery, and pregnancy and labor complications. We used Cox proportional hazard models to calculate covariates adjusted hazard ratios (HRs) for neonatal death (0-27 days of life) among preterm neonates born at 24-27, 28-31, 32-33, and 34-36 weeks of gestation, with preterm labor being the referent.

RESULTS

There were 3,763,306 singleton live births at 24-44 weeks of gestation in the data set. Preterm PROM, indicated preterm birth, and preterm labor had neonatal death risk of 2.7%, 1.8%, and 1.1%, respectively. Compared with preterm labor, preterm PROM had shorter gestational age and lower birth weight, so did indicated preterm birth but to a lesser extent. Preterm PROM and indicated preterm birth after 28 weeks of gestation were associated with higher neonatal death risk than preterm labor. At 34-36 weeks of gestation, the HR of preterm PROM was 1.53 (95% confidence interval 1.20-1.95), and the HR of indicated preterm birth was 2.06 (95% confidence interval 1.83-2.33). The increased risk from preterm PROM and indicated preterm birth was not limited to early neonatal death in the first 7 days.

CONCLUSION

Preterm PROM and indicated preterm birth had higher risk of neonatal death than preterm labor, indicating heterogeneity in gestational age distribution and gestational-age-specific neonatal death risk.

LEVEL OF EVIDENCE

II.

The active management of risk in multiparous pregnancy at term: association between a higher preventive labor induction rate and improved birth outcomes

OBJECTIVE

To determine whether exposure of multiparous women to a high rate of preventive labor induction was associated with a significantly lower cesarean delivery rate.

STUDY DESIGN

Retrospective cohort study involving 123 multiparous women, who were exposed to the frequent use of preventive labor induction, and 304 multiparous women, who received standard management. Rates of cesarean delivery and other adverse birth outcomes were compared in the 2 groups. Logistic regression controlled for confounding covariates.

RESULTS

The exposed group had a lower cesarean delivery rate (adjusted odds ratio, 0.09; 0.8% vs 9.9%; P = .02) and a higher uncomplicated vaginal delivery rate (odds ratio, 0.53; 78.9% vs 66.4%; P = .01). Exposure was not associated with higher rates of other adverse birth outcomes.

CONCLUSION

Exposure of multiparous women to a high rate of preventive labor induction was significantly associated with improved birth outcomes, including a very low cesarean delivery rate. A prospective randomized trial is needed to determine causality.

Minimizing perinatal neurologic injury at term: is cesarean section the answer?

Despite advances in obstetric and neonatal care, the last several decades have not witnessed an improvement in the prediction or prevention of term cerebral palsy. Obstetric interventions such as electronic fetal heart rate monitoring and cesarean delivery, although biologically plausible as intervention strategies, do not improve perinatal outcomes in clinical practice. In reaction to mounting medicolegal pressure, obstetricians continue to increase the number of cesarean deliveries they perform as a form of defensive medicine, despite evidence that this practice is not associated with improved perinatal outcomes. The current standard for expeditious delivery in a case of potential fetal compromise is described by the "30-minute rule." However, obstetricians' determinations of the need for expedited delivery may be a preferable guide for appropriate delivery timing.

Cesarean Delivery for Nonreassuring Fetal Heart Rate Tracing

An understanding of cesarean delivery for nonreassuring fetal heart rate tracing is important for several reasons. This article describes the prevalence of cesarean for nonreassuring fetal heart rate tracing and risk factors, indicates what type of fetal heart rate tracing abnormalities prompts cesarean delivery, reiterates the intrauterine resuscitation that the American College of Obstetricians and Gynecologists guidelines, and suggests steps clinicians should undertake to minimize legal liability.

A randomized clinical trial of the intrapartum assessment of amniotic fluid volume: amniotic fluid index versus the single deepest pocket technique

OBJECTIVE

The purpose of this study was to determine whether an intrapartum assessment of amniotic fluid identifies a pregnancy that is at risk for an adverse outcome.

STUDY DESIGN

Parturients who were admitted for delivery were assigned randomly to have the amniotic fluid assessed either by amniotic fluid index or by the presence of a 2 x 1 pocket.

RESULTS

The amniotic fluid index was obtained in 499 pregnancies, and the 2 x 1 technique was performed in 501. Oligohydramnios was diagnosed in 25% of amniotic fluid index pregnancies versus 8% with the use of the 2 x 1 pocket technique (P <.001). Both techniques failed to identify patients who underwent an amnioinfusion for fetal distress (P=.864) or who experienced variable (P=.208) or late decelerations (P=.210) that influenced delivery, fetal distress in labor (P=.220), caesarean delivery for fetal distress (P=.133), and admission to neonatal intensive care unit (P=.686).

CONCLUSION

Neither the amniotic fluid index nor the 2 x 1 pocket technique that was undertaken as a fetal admission test identifies a pregnancy that is at risk for an adverse outcome.