Presumed Fetal Compromise Research Articles

Effect of intrapartum epidural analgesia on rate of emergency delivery for presumed fetal compromise: nationwide registry-based cohort study.

To determine the rate of emergency delivery for presumed fetal compromise after epidural analgesia (EDA) compared with that after alternative analgesia or no analgesia, and to assess whether this rate is increased in pregnancies with reduced placental reserve. This was a nationwide registry-based cohort study of 629 951 singleton pregnancies delivered at 36 + 0 to 42 + 0 weeks of gestation that were recorded in the Dutch national birth registry between 2014 and 2018, including 120 426 cases that received EDA, 86 957 that received alternative analgesia and 422 568 that received no analgesia during labor. Pregnancies with congenital anomaly, chromosomal abnormality, fetal demise, planned Cesarean delivery, non-cephalic presentation at delivery and use of multiple forms of analgesia were excluded. The primary outcome was emergency delivery for presumed fetal compromise. Secondary outcomes included delivery characteristics and neonatal outcome. Negative binomial regression analysis was stratified by parity and results are presented according to birth-weight centile, after adjusting for confounding. Among women who received EDA, 13.2% underwent emergency delivery for presumed fetal compromise, compared with 4.1% of women who had no analgesia (relative risk (RR), 3.23 (95% CI, 3.16-3.31)) and 7.0% of women who received alternative analgesia (RR, 1.72 (95% CI, 1.67-1.77)). Independent of birth weight, the RR of presumed fetal compromise after EDA vs no analgesia was higher in parous women (adjusted RR (aRR), 2.15 (95% CI, 2.04-2.27)) compared with nulliparous women (RR, 1.88 (95% CI, 1.84-1.94)). Stratified for parity, the effect of EDA was modified significantly by birth-weight centile (interaction P-value, < 0.001 for nulliparous and 0.004 for parous women). The emergency delivery rate following EDA was highest in those with a birth weight < 5th centile (25.2% of nulliparous and 16.6% of parous women), falling with each increasing birth-weight centile category up to the 91st -95th centile (11.8% of nulliparous and 7.2% of parous women). Intrapartum EDA is associated with a higher risk of emergency delivery for presumed fetal compromise compared with no analgesia and alternative analgesia, after adjusting for relevant confounding. The highest rate of emergency delivery for presumed fetal compromise was observed at the lowest birth-weight centiles. RRs of emergency delivery for presumed fetal compromise after EDA were modestly but consistently modified by birth-weight centile, supporting the hypothesis that the adverse effects of EDA are exacerbated by reduced placental function. While EDA provides effective pain relief during labor, alternative strategies for pain management may be preferable in pregnancies with a high background risk of fetal compromise. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Cardiotocography and Clinical Risk Factors in Early Term Labor: A Retrospective Cohort Study Using Computerized Analysis With Oxford System.

ObjectiveThe role of cardiotocography (CTG) in fetal risk assessment around the beginning of term labor is controversial. We used routinely collected clinical data in a large tertiary hospital to investigate whether infants with “severe compromise” at birth exhibited fetal heart rate abnormalities in their first-hour CTGs and/or other clinical risks, recorded as per routine care.Materials and MethodsRetrospective data from 27,927 parturitions (single UK tertiary site, 2001–2010) were analyzed. Cases were included if the pregnancy was singleton, ≥36 weeks' gestation, cephalic presentation, and if they had routine intrapartum CTG as per clinical care. Cases with congenital abnormalities, planned cesarean section (CS), or CS for reasons other than “presumed fetal compromise” were excluded. We analyzed first-hour intrapartum CTG recordings, using intrapartum Oxford System (OxSys) computer-based algorithms. To reflect the effect of routine clinical care, the data was stratified into three exclusive groups: infants delivered by CS for “presumed fetal compromise” within 2 h of starting the CTG (Emergency CS, n = 113); between 2 and 5 h of starting the CTG (Urgent CS, n = 203); and the rest of deliveries (Others, n = 27,611). First-hour CTG and clinical characteristics were compared between the groups, sub-divided to those with and without severe compromise: a composite outcome of stillbirth, neonatal death, neonatal seizures, encephalopathy, resuscitation followed by ≥48 h in neonatal intensive care unit. Two-sample t-test, X2 test, and Fisher's exact test were used for analysis.ResultsCompared to babies without severe compromise, those with compromise had significantly higher proportion of cases with baseline fetal heart rate ≥150 bpm; non-reactive trace; reduced long-term and short-term variability; decelerative capacity; and no accelerations in the first-hour CTG across all groups. Prolonged decelerations(≥3 min) were also more common. Thick meconium and small for gestational age were consistently more common in compromised infants across all groups. There was more often thick meconium, maternal fever ≥38 C, sentinel events, and other clinical risk factors in the Emergency CS and Urgent CS compared to the Others group.ConclusionA proportion of infants born with severe compromise had significantly different first-hour CTG features and clinical risk factors.

Cerebroplacental ratio as a predictor of intrapartum fetal compromise in term pregnancy

To predict intrapartum fetal compromise (FC) and admission to neonatal intensive care unit (NICU) by cerebroplacental ratio (CPR) in term pregnancies. A prospective observational study recruited women with singleton, term pregnancies. Ultrasound (US) was done for fetal biometry, umbilical and middle cerebral artery (UA, MCA) Doppler parameters, and CPR calculated. Intrapartum variables and neonatal data were recorded. Mean interval from US to delivery was 2.21±2.71days. Rate of operative delivery for FC was 17.47%. Multivariate logistic regression analysis showed that UA pulsatility index (PI) multiples of median (MoM) (P=0.001), MCA PI MoM (P=0.001), and CPR MoM (P=0.001) were significantly and independently associated with operative delivery for FC. Similarly, UA PI MoM (P=0.004), MCA PI MoM (P=0.009), and CPR MoM (P=0.003) were also significantly and independently associated with admission to the NICU. Rate of operative delivery for presumed FC was higher in approprate-for-gestational-age fetuses with low CPR than in small-for-gestational-age fetuses with normal CPR (43.1% and 37.5%, respectively). Lower mean CPR and CPR MoM were independently associated with the need for operative delivery for presumed FC and NICU admission at term. CPR is more likely to be associated with FC due to placental insufficiency than birth weight.

Intrapartum hypoxia and sexual dimorphism in adverse perinatal outcomes

ObjectivesThe aim of this study is to evaluate whether markers of intrapartum hypoxia differ according to sex, and if this could explain the increased risk of adverse perinatal outcomes in males. Study designThis is a retrospective observational cohort study of non-anomalous, singleton deliveries >36 completed weeks’ gestation at a UK teaching hospital over a 4.5 year period. Absent or incomplete cord gas results were excluded and the remaining data were validated according to an established method. The relations between sex and both arterial pH and a composite variable, ‘fetal distress’ (cases in which operative delivery or caesarean section were undertaken for presumed fetal compromise), were examined using independent samples t-test and Chi-square test. Odds ratios with 95 % confidence intervals were calculated to describe the relation between fetal sex and intermediate-term adverse outcomes. Binary logistic regression was performed to generate odds ratios (with 95 % confidence intervals) adjusted for arterial pH and fetal distress. This was repeated to adjust for labor and induction of labor. ResultsThere were eligible 8758 cases, of which 4655 were male and 4103 female, from a total of 39,148 deliveries during the study period. Neonatal unit admission (OR 1.54, 95 % CI; 1.31–1.80), renal impairment (OR 1.63, 95 % CI; 1.15–2.32), neurological impairment (OR 1.73, 95 % CI; 1.06–2.84) and a composite adverse outcome (OR 1.73, 95 % CI; 1.29–2.33) were all more likely in males, even after adjusting for labor and induction of labor, both of which were more likely males. The mean cord arterial pH of males was lower (7.23 vs 7.24, P = 0.019) although they were not more likely to be acidemic with a pH <7.0 (males 43 (0.92 %) vs females 41 (1.00 %), P = 0.717), and males were also more likely to have fetal distress (834 (17.9 %) vs 588 (14.3 %), P = <0.001). Being male remained associated with adverse outcomes despite adjustment for arterial pH and fetal distress. ConclusionDespite a lower mean cord arterial pH and greater incidence of fetal distress in males, intrapartum hypoxia does not account for their worse neonatal outcomes.

OP04.05: Prediction of the risk of intrapartum fetal distress using maternal hemodynamics

The aim was to investigate the predictive accuracy of maternal cardiovascular variables for predicting operative delivery due to presumed fetal compromise in women undergoing induction of labour (IOL). This was a prospective cohort study conducted at St. George's University Hospital in London. Women undergoing IOL were invited to participate in the study. A USCOM-1A monitor was used for the cardiovascular evaluation of eligible women. Cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume index (SVI), systemic vascular resistance (SVR) were assessed. Women who delivered via either caesarean or instrumental delivery with an abnormal cardiotocography tracing were evaluated in the operative delivery due to presumed fetal compromise group. A total of 99 women were recruited and four women were later excluded due to elective Caesarean (n=2) and failed IOL (n=2). In the univariate analysis, a CI < 2.9 L/minute (p = 0.043), SV < 65 mL (p = .027), stroke volume index (SVI) < 36 ml/m2 (p = 0.014), SVR > 7.2 logs (p = .020) and SVRI > 7.7 logs (p = 0.023) were significantly associated with the risk of operative delivery. Multiparity was the only maternal risk factor that showed a significant association with the risk of operative delivery in univariate regression model. The baseline model (parity) showed poor predictive accuracy with an area under the curve (AUC) value of 0.67 (95% CI: 0.58-0.77). The addition of SVI < 36 ml/m2, SVR>7.2 logs and SVRI>7.7 logs significantly improved the baseline model (p = 0.012, p = 0.026 and p = 0.012, respectively). The predictive accuracy of models had AUC values of 0.73 (95% CI: 0.64-0.82), 0.73 (95% CI: 0.63-0.84), 0.73 (95% CI: 0.64-0.82) for the combined models with SV, SVR and SVRI respectively. We demonstrated that maternal cardiovascular assessment could be useful for assessing the risk of intrapartum fetal compromise necessitating operative delivery. The addition of SV, SVR and SVRI significantly improved the predictive accuracy of the baseline antenatal model in women undergoing IOL. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Routine assessment of cerebroplacental ratio at 35–37 weeks’ gestation in the prediction of adverse perinatal outcome

Third-trimester studies in selected high-risk pregnancies have reported that low cerebroplacental ratio, due to high pulsatility index in the umbilical artery, and or decreased pulsatility index in the fetal middle cerebral artery, is associated with increased risk of adverse perinatal outcomes. To investigate the predictive performance of screening for adverse perinatal outcome by the cerebroplacental ratio measured routinely at 35-37 weeks' gestation. This was a prospective observational study in 47,211 women with singleton pregnancies undergoing routine ultrasound examination at 35+6 to 37+6 weeks' gestation, including measurement of umbilical artery-pulsatility index and middle cerebral artery-pulsatility index. The measured umbilical artery-pulsatility index and middle cerebral artery-pulsatility index and their ratio were converted to multiples of the median after adjustment for gestational age. Multivariable logistic regression analysis was used to determine whether umbilical artery-pulsatility index, middle cerebral artery-pulsatility index, and cerebroplacental ratio improved the prediction of adverse perinatal outcome that was provided by maternal characteristics, medical history, and obstetric factors. The following outcome measures were considered: (1) adverse perinatal outcome consisting of stillbirth, neonatal death, or hypoxic-ischemic encephalopathy grades 2 and 3; (2) presence of surrogate markers of perinatal hypoxia consisting of umbilical arterial or venous cord blood pH ≤7 and ≤7.1, respectively, 5-minute Apgar score <7, or admission to the neonatal intensive care unit for >24 hours; (3) cesarean delivery for presumed fetal compromise in labor; and (4) neonatal birthweight less than the third percentile for gestational age. First, the incidence of adverse perinatal outcome, presence of surrogate markers of perinatal hypoxia, and cesarean delivery for presumed fetal compromise in labor was greater in pregnancies with small for gestational age neonates with birthweight <10th percentile compared with appropriate for gestational age neonates; however, 80%-85% of these adverse events occurred in the appropriate for gestational age group. Second, low cerebroplacental ratio <10th percentile was associated with increased risk of adverse perinatal outcome, presence of surrogate markers of perinatal hypoxia, cesarean delivery for presumed fetal compromise in labor, and birth of neonates with birthweight less than third percentile. However, multivariable regression analysis demonstrated that the prediction of these adverse outcomes by maternal demographic characteristics and medical history was only marginally improved by the addition of cerebroplacental ratio. Third, the performance of low cerebroplacental ratio in the prediction of each adverse outcome was poor, with detection rates of 13%-26% and a false-positive rate of about 10%. Fourth, the detection rates of adverse outcomes were greater in small for gestational age than in appropriate for gestational age babies and in pregnancies delivering within 2 weeks rather than at any stage after assessment; however, such increase in detection rates was accompanied by an increase in the false-positive rate. Fifth, in appropriate for gestational age neonates, the predictive accuracy of cerebroplacental ratio was low, with positive and negative likelihood ratios ranging from 1.21 to 1.82, and0.92 to 0.98, respectively; although the accuracy was better in smallfor gestational age neonates, this was also low with positive likelihood ratios of 1.31-2.26 and negative likelihood ratios of 0.69-0.92. Similar values were obtained in fetuses classified as small for gestational age and appropriate for gestational age according to the estimated fetal weight. In pregnancies undergoing routine antenatal assessment at 35-37 weeks' gestation, measurement of cerebroplacental ratio provides poor prediction of adverse perinatal outcome in both small for gestational age and appropriate for gestational age fetuses.

Risk of operative delivery for intrapartum fetal compromise in small-for-gestational-age fetuses at term: external validation of the IRIS algorithm

Objectives: Small-for-gestational-age fetuses (SGA) are at high risk of intrapartum fetal compromise requiring operative delivery. In a recent study, we developed a model using a combination of three antenatal (gestational age at delivery, parity, cerebroplacental ratio) and three intrapartum (epidural use, labor induction and augmentation using oxytocin) variables for the prediction of operative delivery due to presumed fetal compromise in SGA fetuses – the Individual RIsk aSsessment (IRIS) prediction model. The aim of this study was to test the predictive accuracy of the IRIS prediction model in an external cohort of singleton pregnancies complicated by SGA.Methods: This was an external validation study using a cohort of pregnancies from two tertiary referral centers in Spain and England. The inclusion criteria were singleton pregnancies diagnosed with an SGA fetus, defined as estimated fetal weight (EFW) below the 10th centile for gestational age at 36 weeks or beyond, which had fetal Doppler assessment and available data on their intrapartum care and pregnancy outcomes. The main outcome in this study was the operative delivery for presumed fetal compromise. External validation was performed using the coefficients obtained in the original development cohort. The predictive accuracies of models were investigated with receiver operating characteristics (ROC) curves. The Hosmer–Lemeshow test was used to test the goodness-of-fit of models and calibration plots were also obtained for visual assessment. A mobile application using the combined model algorithm was developed to facilitate clinical use.Results: Four hundred twelve singleton pregnancies with an antenatal diagnosis of SGA were included in the study. The operative delivery rate was 22.8% (n = 94). The group which required operative delivery for presumed fetal compromise had significantly fewer multiparous women (19.1 versus 47.8%, p < .001 in the total study population; 19.0 versus 43.5 and 19.2 versus 49.6%, UK and Spain cohort, respectively), lower cerebroplacental ratio (CPR) multiples of median (MoM) (median: 0.77 versus 0.92, p < .001 in the total study population; 0.77 versus 0.92 and 0.77 versus 0.92, UK and Spain cohort, respectively), more inductions of labor (74.5 versus 60.1%, p = .010 in the total study population; 85.7 versus 77.2 and 71.2% and 53.1, UK and Spain cohort, respectively) and more use of oxytocin augmentation (57.4 versus 39.3%, p = .002 in the total study population; 19.0 versus 12.0 and 68.5 and 50.4%, UK and Spain cohort, respectively) compared to those who did not require operative delivery due to presumed fetal compromise. When the original antenatal model was applied to the present cohort, we observed moderate predictive accuracy (AUC: 0.70, 95% CI: 0.64–0.76), and no signs of poor fit (p = .464). The original combined model, when applied to the external cohort, had moderate predictive accuracy (AUC: 0.72, 95% CI: 0.67–0.77) and also no signs of poor fit (p = .268) without the need for refitting. A statistically significant increase in the predictive accuracy was not achieved via refitting of the combined model (AUC 0.76 versus 0.72, p = .060).Conclusions: Using our recently published model, the predictive accuracy for fetal compromise requiring operative delivery in term fetuses thought to be SGA was modest and showed no signs of poor fit in an external cohort. The IRIS tool for mobile devices has been developed to facilitate wide clinical use of this prediction model.Brief rationaleObjective: To determine the external validity of an intrapartum risk prediction model for suspected small-for-gestational age fetuses.What is already known: Small-for-gestational age fetuses are at increased risk of intrapartum compromise. Fetal weight alone is a poor marker for adverse outcomes and a comprehensive prediction model has been previously suggested.What this study adds: Multivariable prediction model showed good accuracy and calibration in this external validation study. The significance of some variables was different between the original and external validation cohort and there was a small margin for improvement with model refitting. A mobile application has been developed to facilitate clinical use.

Is cerebroplacental ratio a marker of impaired fetal growth velocity and adverse pregnancy outcome?

The cerebroplacental ratio has been proposed as amarker of failure to reach growth potential near term. Low cerebroplacental ratio, regardless of the fetal size, is independently associated with the need for operative delivery for presumed fetal compromise and with neonatal unit admission at term. The main aim of this study was to evaluate whether the cerebroplacental ratio at term is a marker of reduced fetal growth rate. The secondary aim was to investigate the relationship between a low cerebroplacental ratio at term, reduced fetal growth velocity, and adverse pregnancy outcome. This was a retrospective cohort study of singleton pregnancies in a tertiary referral center. The abdominal circumference was measured at 20-24 weeks' gestation and both abdominal circumference and fetal Dopplers recorded at or beyond 35 weeks, within 2 weeks of delivery. Abdominal circumference and birthweight values were converted into Z scores and centiles, respectively, and fetal Doppler parameters into multiples of median, adjusting for gestational age. Abdominal circumference growth velocity was quantified using the difference in the abdominal circumference Z score, comparing the scan at or beyond 35 weeks with the scan at 20-24 weeks. Both univariable and multivariable logistic regression analyses were performed to investigate the association between low cerebroplacental ratio and the low abdominal circumference growth velocity (in the lowest decile) and to identify and adjust for potential confounders. As a sensitivity analysis, we refitted the model excluding the data on pregnancies with small-for-gestational-age neonates. The study included 7944 pregnancies. Low cerebroplacental ratio multiples of median was significantly associated with both low abdominal circumference growth velocity (adjusted odds ratio, 2.10; 95% confidence interval, 1.71-2.57, P <0.001) and small for gestational age(adjusted odds ratio, 3.60; 95% confidence interval, 3.04-4.25, P<.001). After the exclusion of pregnancies resulting in small-for-gestational-age neonates, a low cerebroplacental ratio multiples of the median remained significantly associated with both low abdominal circumference growth velocity (adjusted odds ratio, 1.76; 95% confidence interval, 1.34-2.30, P < .001) and birthweight centile (adjusted odds ratio, 0.99; 95% confidence interval, 0.998-0.995, P < .001). The need for operative delivery for fetal compromise was significantly associated with a low cerebroplacental ratio (adjusted odds ratio, 1.40; 95% confidence interval, 1.10-1.78, P= .006), even after adjusting for both the umbilical artery pulsatility index multiples of the median and middle cerebral artery pulsatility index multiples of median. The results were similar, even after the exclusion of pregnancies resulting in small-for-gestational-age neonates (adjusted odds ratio, 1.39; 95% confidence interval, 1.06-1.84, P= .018). Low cerebroplacental ratio multiples of the median remained significantly associated with the risk of operative delivery for presumed fetal compromise (P < .001), even after adjusting for the known antenatal and intrapartum risk factors. These associations persisted, even after the exclusion of small-for-gestational-age births. In appropriate-for-gestational-age-sized fetuses, abdominal circumference growth velocity was significantly lower in those with a low cerebroplacental ratio multiples of the median than in those with normal cerebroplacental ratio multiples of the median (P < .001). The cerebroplacental ratio is a marker of impaired fetal growth velocity and adverse pregnancy outcome, even in fetuses whose size is considered appropriate using conventional biometry.

Can the cerebroplacental ratio (CPR) predict intrapartum fetal compromise? A prospective observational study

Objective: To investigate the potential clinical use of serial fetal CPR measurements during the last month of pregnancy for the prediction of adverse perinatal outcome in unselected low-risk pregnancies. Methods: A multicenter prospective observational cohort study in 315 consecutively recruited low-risk pregnancies. All eligible pregnancies underwent serial sonographic evaluation of fetal weight and Doppler indices at two week intervals, from 36 weeks gestation until delivery. Data were converted into centiles correcting for gestational age. These data were not available for the obstetrical team and hence, could not influence management decisions. Primary outcomes were operative delivery for presumed fetal compromise and a composite neonatal outcome (arterial cord Ph 90th centile). Results: Three hundred fifteen women were recruited in this study. We ecxluded 32 pregnancies because of small for gestational age babies (SGA), leaving 293 women and 583 CPR values for data-analysis. There were 85 (27%) adverse neonatal outcomes and 29 patients (9%) underwent operative delivery for presumed fetal compromise. Both primary and secondary outcomes were not significant different between the different CPR groups. Furthermore, we examined if individual serial CPR measurements could predict adverse outcome and found no linear correlation between repeated measurements of CPR and adverse outcomes. Conclusion: Our study shows that routine serial screening by CPR measurements provides poor prediction for adverse perinatal outcome in uncomplicated pregnancies.

Are fetuses that fail to achieve their growth potential at increased risk of intrapartum compromise?

The true growth potential of a fetus is difficult to predict but recently a new definition, independent of fetal weight, using cerebroplacental (cerebro-umbilical) ratio (CPR) < 0.6765 multiples of the median (MoM), was reported. We applied this definition to a cohort of low-risk pregnancies recruited prospectively to determine if fetuses with CPR < 0.6765 are at increased risk of developing signs of intrapartum fetal compromise. Recruitment to this prospective observational study took place between March 2011 and March 2014. All women with low-risk singleton pregnancies at term were eligible. Women with known or suspected placental dysfunction were excluded, as were women with fetuses with an estimated fetal weight < 10(th) centile. All participants underwent ultrasound examination prior to active labor (≤ 4 cm cervical dilatation), during which fetal biometry as well as umbilical artery and fetal middle cerebral artery blood flow were assessed. Following delivery, intrapartum and neonatal outcomes were compared between fetuses that had a CPR < 0.6765 MoM and those that had a CPR ≥ 0.6765 MoM. In total, 775 women were recruited. Fetuses with CPR < 0.6765 MoM were significantly more likely to require Cesarean delivery because of presumed fetal compromise (P < 0.001). These fetuses were also at increased risk of compromise at any time during labor and were less likely to be delivered vaginally, spontaneously or otherwise, than were those with CPR ≥ 0.6765 MoM. CPR < 0.6765 MoM gave a positive predictive value (PPV) for Cesarean delivery because of presumed fetal compromise of 36.7% and a negative predictive value of 88.7%, with a sensitivity of 18% and a specificity of 95.4%. Fetuses that failed to achieve their growth potential (defined as CPR < 0.6765 MoM) were at increased risk of intrapartum compromise and were less likely to be delivered vaginally. However, a low negative predictive value was observed for fetal compromise and further studies are required to support the translation of this technique into clinical practice.

Is fetal cerebroplacental ratio an independent predictor of intrapartum fetal compromise and neonatal unit admission?

We sought to evaluate the association between fetal cerebroplacental ratio (CPR) and intrapartum fetal compromise and admission to the neonatal unit (NNU) in term pregnancies. This was a retrospective cohort study in a single tertiary referral center over a 14-year period from 2000 through 2013. The umbilical artery pulsatility index, middle cerebral artery pulsatility index, and CPR were recorded within 2 weeks of delivery. The birthweight (BW) values were converted into centiles and Doppler parameters converted into multiples of median (MoM), adjusting for gestational age using reference ranges. Logistic regression analysis was performed to identify, and adjust for, potential confounders. The study cohort included 9772 singleton pregnancies. The rates of operative delivery for presumed fetal compromise and neonatal admission were 17.2% and 3.9%, respectively. Doppler CPR MoM was significantly lower in pregnancies requiring operative delivery or admission to NNU for presumed fetal compromise (P < .01). On multivariate logistic regression, both CPR MoM and BW centile were independently associated with the risk of operative delivery for presumed fetal compromise (adjusted odds ratio [OR], 0.67; 95% confidence interval [CI], 0.52-0.87; P = .003 and adjusted OR, 0.994; 95% CI, 0.992-0.997; P < .001, respectively). The latter associations persisted even after exclusion of small-for-gestational-age cases from the cohort. Multivariate logistic regression also demonstrated that CPR MoM was an independent predictor for NNU admission at term (adjusted OR, 0.55; 95% CI, 0.33-0.92; P = .021), while BW centile was not (adjusted OR, 1.00; 95% CI, 0.99-1.00; P = .794). The rates of operative delivery for presumed fetal compromise were significantly higher for appropriate-for-gestational-age fetuses with low CPR MoM (22.3%) compared to small-for-gestational-age fetuses with normal CPR MoM (17.3%). Lower fetal CPR, regardless of the fetal size, was independently associated with the need for operative delivery for presumed fetal compromise and with NNU admission at term. The extent to which fetal hemodynamic status could be used to predict perinatal morbidity and optimize the mode of delivery merits further investigation.

Mode of delivery has an independent impact on neonatal condition at birth

ObjectiveCurrent intra-partum monitoring techniques are often criticized for their poor specificity, with their performance frequently evaluated using measures of the neonatal condition at birth as a surrogate marker for intra-partum fetal compromise. However, these measures may potentially be influenced by a multitude of other factors, including the mode of delivery itself. This study aimed to investigate the impact of mode of delivery on neonatal condition at birth. Study designThis prospective observational study, undertaken at a tertiary referral maternity unit in London, UK, included 604 ‘low risk’ women recruited prior to delivery. Commonly assessed neonatal outcome variables (Apgar score at 1 and 5min, umbilical artery pH and base excess, neonatal unit admission, and a composite neonatal outcome score) were used to compare the condition at birth between babies born by different modes of delivery, using one-way ANOVA and chi-squared testing. ResultsInfants born by instrumental delivery for presumed fetal compromise had the poorest condition at birth (mean composite score=1.20), whereas those born by Cesarean section for presumed fetal compromise had a better condition at birth (mean composite score=0.64) (p=<0.001). No difference in composite neonatal outcome scores was observed between babies born by instrumental delivery for a prolonged second stage (no evidence of compromise), and those born by Cesarean delivery for presumed fetal compromise. ConclusionsMode of delivery represents a potential confounding factor when using condition at birth as a surrogate marker of intra-partum fetal compromise. When evaluating the efficacy of intra-partum monitoring techniques, the isolated use of Apgar scores, umbilical artery acidosis and neonatal unit admission should be discouraged.

Umbilical venous flow rate in term fetuses: can variations in flow predict intrapartum compromise?

The objective of the study was to investigate the distribution of umbilical venous flow rates, measured in early labor, in a cohort of normal term pregnancies and to establish the relationship between umbilical venous flow and subsequent intrapartum outcome. Five hundred eighty-nine women with uncomplicated, term, singleton pregnancies were recruited to this prospective observational study prior to active labor (dilation of 4 cm or less) at Queen Charlotte's and Chelsea Hospital (London, UK). All participants underwent an ultrasound examination, during which fetal biometry, umbilical venous flow velocity, and umbilical vein diameter were recorded. Umbilical venous flow rate was then calculated. Following delivery, intrapartum and neonatal outcomes were correlated with the ultrasound findings. Cases were subdivided according to mode of delivery, and mean umbilical venous flow rates were compared between the groups. Cases were also subdivided according to umbilical venous flow rate (less than the 20th centile, 20th-80th centile, and greater than the 80th centile), and the incidence of diagnoses of fetal compromise was compared. Fetuses delivered by emergency cesarean for presumed fetal compromise had the lowest umbilical venous flow rates (both corrected for and uncorrected for birthweight) (P= .02 and P= .001, respectively). Fetuses with the lowest umbilical venous flow rates were significantly more likely to require emergency cesarean for presumed fetal compromise than those with the highest flow rates (15.7% vs 5.6%, relative risk, 2.83; 95% confidence interval, 1.16-6.91). Fetuses with the lowest umbilical venous flow rates are at increased risk of a subsequent diagnosis of intrapartum fetal compromise. Measurement of umbilical venous flow could contribute to the risk stratification of pregnancies prior to labor.

3.1 Prediction of Fetal Compromise: The Use of Fetal Doppler Assessment in Normal Pregnancies Prior to Labour

IntroductionUp to 63% of cases of intra-partum hypoxia occur in pregnancies with no antenatal risk factors. Identification before labour of these antenatally normal fetuses at risk of intra-partum hypoxia would...

Mode of anaesthetic for category 1 caesarean sections and neonatal outcomes

Birth by emergency caesarean section (CS) is common and often considered urgent (category 1). In the UK, over half of all category 1 CS are performed under general anaesthesia (GA). In this setting, little is known about the effect of the mode of anaesthesia on the neonate. A retrospective cohort study was performed using routinely collected de-identified data from Mater Health Services, Brisbane, Australia. The data set included 533 term babies born by category 1 CS for presumed fetal compromise between 2008 and 2011. Bivariate and multivariate analyses were undertaken. The outcomes of 81 babies born by GA CS were compared with 452 by CS under regional anaesthesia (RA). Compared with a category 1 CS under RA, the decision-to-delivery interval for a GA CS was almost eight minutes faster (24.7 vs 32.6 minutes; P < 0.001). When adjusted for confounders, babies born by category 1 GA CS were significantly more likely to have an Apgar score < 7 at five minutes (aOR 6.89; 95%CI 1.79-26.55; P = 0.005), to require Neopuff or bag/mask ventilation for > 60 seconds (aOR 2.34; 95%CI 1.13-4.84; P = 0.022) and to be admitted to a neonatal intensive care nursery (aOR 2.24; 95%CI 1.16-4.31; P = 0.016). General anaesthesia was associated with short-term neonatal morbidity of term babies born by category 1 CS for presumed fetal compromise, despite enabling a more rapid delivery of the baby. These data should help inform the discussion between anaesthetist and obstetrician, in balancing the risks and benefits of the mode of anaesthesia.

The role of instrumental vaginal delivery in low resource settings

This commentary discusses instrumental vaginal delivery (IVD) and the issues experienced with that practice in low resource settings. It states that IVD is a key element of essential obstetric care and the improvement of maternal and neonatal outcomes will require the scaling up of IVD use with the provision of equipment and trained operators to areas where they are currently unavailable.

Caesarean delivery at full cervical dilatation versus caesarean delivery in the first stage of labour: comparison of maternal and perinatal morbidity

To compare perinatal and maternal morbidity associated with caesarean sections performed in the first with that performed in the second stages of labour. Comparative analyses between nulliparous women with singleton term pregnancies who had a caesarean section in the first stage of labour and those who had a second stage caesarean section were completed using standard statistical methods. A subgroup analysis, according to indication for caesarean section, was also performed. Of 627 women, 81% had caesarean delivery in the first stage and 19% had caesarean delivery in the second stage of labour. Women undergoing caesarean delivery at full cervical dilatation were 1.9 times more likely to have an augmented labour (95% CI 1.2-3.4, P < 0.001) and 2.8 times more likely to have epidural anaesthesia in labour (95% CI 1.5-5.2, P < 0.001) than those in the first stage. Compared with caesarean delivery in the first stage of labour, women undergoing caesarean delivery at full cervical dilatation were 4.6 times more likely to have composite intraoperative complications (95% CI 2.7-7.9, P < 0.001), 3.1 times more likely to have blood loss greater than 1,000 ml (95% CI 1.3-7.4, P = 0.01), and 2.9 times more likely to have a blood transfusion (95% CI 1.5-5.6, P < 0.001). The risk of neonatal morbidity was higher in first stage caesareans when they were performed for presumed fetal compromise (66.3 vs. 26.3%, P = 0.002), and lower when they were performed for failure to progress (18.4 vs. 42%, P = 0.02). Caesarean section in the second stage of labour is associated with a higher risk of maternal but not perinatal morbidity.

Reproducibility of the ventilatory response of the newborn to carbon dioxide during sleep : G. Cohen, C. Xu and D.J. Henderson-Smart, (Introduced by A. Wilkinson), Perinatal Medicine, King George V Hospital, Sydney, Australia

The cerebroplacental ratio has been proposed as a marker of failure to reach growth potential near term. Low cerebroplacental ratio, regardless of the fetal size, is independently associated with the need for operative delivery for presumed fetal compromise and with neonatal unit admission at term.The main aim of this study was to evaluate whether the cerebroplacental ratio at term is a marker of reduced fetal growth rate. The secondary aim was to investigate the relationship between a low cerebroplacental ratio at term, reduced fetal growth velocity, and adverse pregnancy outcome.This was a retrospective cohort study of singleton pregnancies in a tertiary referral center. The abdominal circumference was measured at 20–24 weeks’ gestation and both abdominal circumference and fetal Dopplers recorded at or beyond 35 weeks, within 2 weeks of delivery. Abdominal circumference and birthweight values were converted into Z scores and centiles, respectively, and fetal Doppler parameters into multiples of median, adjusting for gestational age. Abdominal circumference growth velocity was quantified using the difference in the abdominal circumference Z score, comparing the scan at or beyond 35 weeks with the scan at 20–24 weeks. Both univariable and multivariable logistic regression analyses were performed to investigate the association between low cerebroplacental ratio and the low abdominal circumference growth velocity (in the lowest decile) and to identify and adjust for potential confounders. As a sensitivity analysis, we refitted the model excluding the data on pregnancies with small-for-gestational-age neonates.The study included 7944 pregnancies. Low cerebroplacental ratio multiples of median was significantly associated with both low abdominal circumference growth velocity (adjusted odds ratio, 2.10; 95% confidence interval, 1.71–2.57, P <0.001) and small for gestational age (adjusted odds ratio, 3.60; 95% confidence interval, 3.04–4.25, P < .001). After the exclusion of pregnancies resulting in small-for-gestational-age neonates, a low cerebroplacental ratio multiples of the median remained significantly associated with both low abdominal circumference growth velocity (adjusted odds ratio, 1.76; 95% confidence interval, 1.34–2.30, P < .001) and birthweight centile (adjusted odds ratio, 0.99; 95% confidence interval, 0.998–0.995, P < .001). The need for operative delivery for fetal compromise was significantly associated with a low cerebroplacental ratio (adjusted odds ratio, 1.40; 95% confidence interval, 1.10–1.78, P = .006), even after adjusting for both the umbilical artery pulsatility index multiples of the median and middle cerebral artery pulsatility index multiples of median. The results were similar, even after the exclusion of pregnancies resulting in small-for-gestational-age neonates (adjusted odds ratio, 1.39; 95% confidence interval, 1.06–1.84, P = .018). Low cerebroplacental ratio multiples of the median remained significantly associated with the risk of operative delivery for presumed fetal compromise (P < .001), even after adjusting for the known antenatal and intrapartum risk factors. These associations persisted, even after the exclusion of small-for-gestational-age births. In appropriate-for-gestational-age–sized fetuses, abdominal circumference growth velocity was significantly lower in those with a low cerebroplacental ratio multiples of the median than in those with normal cerebroplacental ratio multiples of the median (P < .001).The cerebroplacental ratio is a marker of impaired fetal growth velocity and adverse pregnancy outcome, even in fetuses whose size is considered appropriate using conventional biometry.

Medical needs in the Gold Coast.

<h3>Introduction</h3> Up to 63% of cases of intra-partum hypoxia occur in pregnancies with no antenatal risk factors. Identification before labour of these antenatally normal fetuses at risk of intra-partum hypoxia would enable a more targeted approach to intra-partum care. <h3>Methods</h3> Five hundred and eleven women with uncomplicated, term, singleton pregnancies, underwent a pre-labour ultrasound assessment. This included measurement of fetal biometry, Umbilical artery, Middle cerebral artery, and Umbilical venous resistance indices. Clinicians managing the labour were blinded to the ultrasound results. Following delivery, case notes were reviewed and intra-partum outcomes correlated with ultrasound findings. <h3>Results</h3> Infants born by Caesarean section for presumed fetal compromise had the highest Umbilical artery pulsatility index (p = 0.002), the lowest Middle cerebral artery pulsatility index (p &lt; 0.001), the lowest cerebro-umbilical ratio (p &lt; 0.001), the lowest Umbilical venous flow rates (p = 0.003), and the highest cerebral blood flow of any mode of delivery group (p = 0.007). A cerebro-umbilical ratio &lt;10th centile has a positive predictive value of 36% for Caesarean section for presumed fetal compromise. This can be improved to 61.5% by inclusion of the other Doppler parameters. A cerebro-umbilical ratio &gt;90th centile has a 100% negative predictive value. <h3>Conclusion</h3> Pre labour fetal Doppler assessment can identify fetuses at both high and low risk of subsequent compromise in labour. Current intra-partum monitoring has a high false positive rate, which could be improved by better risk stratification prior to labour. This technique is easily translatable into clinical practise and would allow risk stratification of normal pregnancies prior to labour, enabling a more targeted approach to intra-partum care.