Cerebroplacental ratio assessment in early labor in uncomplicated term pregnancy and prediction of adverse perinatal outcome: prospective multicenter study

Comparison of maternal and neonatal outcomes between vaginal birth after cesarean section and normal vaginal birth

OBJECTIVE

This study aimed to compare the outcomes of vaginal birth after cesarean (VBAC) with those of normal vaginal birth (NVB) in a tertiary hospital in China.

METHODS

This retrospective cohort study analyzed 1,024 women who birthed vaginally between January 2019 and December 2020. The VBAC group (n = 512) included women with one previous cesarean, while the NVB group (n = 512) had no previous caesareans. All women used epidural analgesia. We assessed maternal and neonatal complications using descriptive statistics, chi-square tests, and logistic regression. Statistical analysis was performed using SPSS version 25.0.

RESULTS

The VBAC group had an 87.5% success rate for vaginal birth under epidural analgesia, whereas the NVB group had a 100% success rate. A primary focus of the study was uterine rupture. Vaginal birth after cesarean was associated with a higher incidence of uterine rupture (0.8% vs 0%, p = 0.031), postpartum hemorrhage (6.6% vs 3.5%, p = 0.021) and the need for blood transfusions (2.7% vs 0.8%, p = 0.012) compared with NVB. There were no substantial differences in maternal infections, wound infections or perineal lacerations between the groups. Although neonatal outcomes were generally similar, the VBAC group experienced higher rates of 5-minute Apgar scores <7 (2.3% vs 0.6%, p = 0.009) and admissions to neonatal intensive care units (3.1% vs 1.2%, p = 0.016 Even after adjusting for confounders, VBAC remained an independent risk factor for several complications.

CONCLUSION

Although VBAC is feasible and mostly safe, it is associated with a higher risk of specific complications compared with NVB. Careful selection of candidates and close monitoring are essential for optimizing outcomes in VBAC cases.

Cerebroplacental ratio and perinatal outcomes in mild-to-moderate idiopathic polyhydramnios cases

OBJECTIVE

This study will evaluate whether fetal cerebroplacental ratio (CPR) can predict perinatal adverse outcomes in singleton pregnancies with mild and moderate idiopathic polyhydramnios (IP).

METHOD

This study was designed as a prospective case-control study between January 2023 and November 2023. Pregnant women diagnosed with mild-to-moderate IP and low-risk singleton pregnancies were included in the study. In all cases, umbilical artery (UA) and middle cerebral artery (MCA) pulsatility indices (PIs) were measured at 36-40 weeks of gestation, and CPR was calculated. The group with polyhydramnios was divided into two parts according to whether the CPR value was below 1.08 or 1.08 and above. Perinatal outcomes of all groups were compared.

RESULTS

A total of 140 patients were included in the study. Seventy of these were IP cases, and 70 were low-risk pregnant women. UA PI in the IP group was not statistically different from that in the low-risk group, but MCA PI and CPR were significantly lower in the IP group (P = 0.07, P = 0.001, and P = 0.004, respectively). IP cases were divided into a low group (<1.08, n = 18) and a normal group (≥1.08, n = 52) according to the CPR value. Cesarean section rates due to fetal distress were significantly higher in the low-CPR group (n = 8 [44.4%] vs 5 [9.6%], P = 0.001). In the low-CPR group, 5-min Apgar <7, and neonatal intensive care unit (NICU) admission rates were significantly higher (P = 0.045 and P = 0.001, respectively).

CONCLUSION

It is encouraging that in cases with mild-to-moderate IP, low CPR predicts emergency delivery due to fetal distress, a low Apgar score at 5 min, and NICU admission.

Amniotic-umbilical-to-cerebral ratio, a Doppler index for estimating adverse perinatal outcomes in fetal growth restriction

OBJECTIVE

To evaluate amniotic fluid volume with Doppler parameters and its association with composite adverse perinatal outcomes (CAPOs) in fetal growth restriction (FGR).

MATERIALS AND METHODS

This study was conducted prospectively in a tertiary referral center between 2023 and 2024 on pregnant women diagnosed with early- and late-onset FGR. Fetal ultrasonographic measurements, including deepest vertical pocket (DVP) for amniotic fluid, and Doppler parameters including uterine artery (UtA) systolic/diastolic (S/D) and pulsatility index (PI), middle cerebral artery (MCA) S/D and PI, and umbilical artery (UA) S/D and PI, were conducted following fetal biometry. The cerebroplacental ratio (CPR), cerebral ratio, cerebro-placental-uterine ratio (CPUR), and amniotic-umbilical-to-cerebral ratio (AUCR) were all calculated. Pregnant women diagnosed with FGR were planned to give birth after 37 weeks' gestation, unless a pregnancy complication requiring earlier delivery occurred. We assessed perinatal outcomes subsequent to delivery, with CAPOs defined as the presence of at least one adverse outcome: 5th minute APGAR score <7, respiratory distress syndrome (RDS), umbilical cord blood pH <7.2, and neonatal intensive care unit (NICU) admission.

RESULTS

The study included 132 participants, divided into early- (n = 32) and late-onset FGR (n = 100) groups. AUCR was significantly lower in fetuses with late-onset FGR who experienced CAPOs. Multivariate analysis showed gestational age at birth and birth weight were significant predictors of CAPOs in early-onset FGR, while gestational age, birth weight, and AUCR were significant predictors in late-onset FGR. CPR, UCR, and CPUR did not show significance in predicting CAPOs in both early- and late-onset FGR on multivariate analysis.

CONCLUSIONS

AUCR is a potential reliable marker for predicting adverse perinatal outcomes in late-onset FGR.

Relative uteroplacental insufficiency of labor

Relative uteroplacental insufficiency of labor (RUPI-L) is a clinical condition that refers to alterations in the fetal oxygen "demand-supply" equation caused by the onset of regular uterine activity. The term RUPI-L indicates a condition of "relative" uteroplacental insufficiency which is relative to a specific stressful circumstance, such as the onset of regular uterine activity. RUPI-L may be more prevalent in fetuses in which the ratio between the fetal oxygen supply and demand is already slightly reduced, such as in cases of subclinical placental insufficiency, post-term pregnancies, gestational diabetes, and other similar conditions. Prior to the onset of regular uterine activity, fetuses with a RUPI-L may present with normal features on the cardiotocography. However, with the onset of uterine contractions, these fetuses start to manifest abnormal fetal heart rate patterns which reflect the attempt to maintain adequate perfusion to essential central organs during episodes of transient reduction in oxygenation. If labor is allowed to continue without an appropriate intervention, progressively more frequent, and stronger uterine contractions may result in a rapid deterioration of the fetal oxygenation leading to hypoxia and acidosis. In this Commentary, we introduce the term relative uteroplacental insufficiency of labor and highlight the pathophysiology, as well as the common features observed in the fetal heart rate tracing and clinical implications.

Prediction of Cesarean Section for Intrapartum Fetal Compromise: A Multivariable Model from a Prospective Observational Approach

OBJECTIVE

A cesarean section for intrapartum fetal compromise (IFC) is performed to avoid potential damage to the newborn. It is, therefore, crucial to develop an accurate prediction model that can anticipate, prior to labor, which fetus may be at risk of presenting this condition.

MATERIAL AND METHODS

To calculate a prediction model for IFC, the clinical, epidemiological, and ultrasonographic variables of 538 patients admitted to the maternity of La Fe Hospital were studied and evaluated using univariable and multivariable logistic regression analysis, using the area under the curve (AUC) and the Akaike Information Criteria (AIC).

RESULTS

In the univariable analysis, CPR MoM was the best single parameter for the prediction of CS for IFC (OR 0.043, p < 0.0001; AUC 0.72, p < 0.0001). Concerning the multivariable analysis, for the general population, the best prediction model (lower AIC) included the CPR multiples of the median (MoM), the maternal age, height, and parity, the smoking habits, and the type of labor onset (spontaneous or induction) (AUC 0.80, p < 0.0001). In contrast, for the pregnancies undergoing labor induction, the best prediction model included the CPR MoM, the maternal height and parity, and the smoking habits (AUC 0.80, p < 0.0001). None of the models included estimated fetal weight (EFW).

CONCLUSIONS

CS for IFC can be moderately predicted prior to labor using maternal characteristics and CPR MoM. A validation study is pending to apply these models in daily clinical practice.

Morphometric Analysis of Placenta and Fetal Doppler Indices in Normal and High-Risk Pregnancies

Background High-risk pregnancies, encompassing pregnancy-induced hypertension (PIH), gestational diabetes mellitus (GDM), preeclampsia toxemia (PET), and intrauterine growth restriction (IUGR), represent intricate medical challenges with potential repercussions for maternal and fetal health. This research undertakes a comprehensive comparative investigation into the variations of Doppler indices and placental parameters within the context of these high-risk conditions when juxtaposed against pregnancies characterized as normal. Methodology Employing a rigorous cross-sectional study design, a diverse cohort of pregnant individuals with gestational diabetes, IUGR, PIH, and preeclampsia was meticulously assembled. Additionally, a group of normal pregnant women served as the comparative reference. Doppler ultrasound assessments, viz, pulsatility index (PI), were carefully performed to estimate blood flow velocities within critical maternal and fetal vessels, while placental parameters were meticulously quantified, encompassing dimensions, vascular architecture, and morphological features. Results Except in the GDM group, all high-risk groups had reduced estimated placental weight and actual birth weight than normal pregnant women. All high-risk groups showed a highly significant elevation of the PI of the umbilical artery and PI of the middle cerebral artery (MCA) than normal but the PI of MCA was significantly reduced in the PET group than in normal individuals. The cerebro-placental ratio in the GDM and IUGR groups revealed markedly greater values, whereas PET showed lower values. IUGR and PIH groups showed a substantial reduction in the fetal birth weight. All high-risk groups (GDM, IUGR, PIH, and PET) showed a highly significant reduction in luminal area umbilical artery 1 than the normal pregnant women. In IUGR, marginal placental insertion was very high, followed by GDM and PET groups. Conclusions This study reveals that Doppler indices, placental parameters, newborn weight, and their related ratios may be utilized to anticipate gestation difficulties and gain insight into the pathophysiology of problematic conceptions.

Association of umbilical vein flow with abnormal fetal growth and adverse perinatal outcome in low-risk population: multicenter prospective study

OBJECTIVE

To investigate the relationship of umbilical vein flow (UVF) measured close to term with abnormal fetal growth and adverse perinatal outcome in a cohort of pregnancies at low risk of placental insufficiency.

METHODS

This was a prospective multicenter observational study conducted across two tertiary maternity units. Patients with a singleton appropriate-for-gestational-age fetus between 35 and 38 weeks' gestation were included. Pregnancies at higher risk of placental insufficiency or with fetal anomalies were excluded. At ultrasound examination, the abdominal circumference (AC), umbilical vein diameter and peak velocity of the umbilical vein were measured, and, using these variables, a new variable, UVF/AC, was calculated. The primary outcome was the occurrence of severely stunted fetal growth, defined as a greater than 40-percentile drop between estimated fetal weight at the third-trimester ultrasound and birth weight. The occurrence of adverse perinatal outcome (defined as one of the following: neonatal acidosis (umbilical artery pH < 7.15 and/or base excess > 12 mmol/L) at birth, 5-min Apgar score < 7, neonatal resuscitation or neonatal intensive care unit admission) was analyzed as a secondary outcome.

RESULTS

Between April 2021 and March 2023, 365 women were included in the study. The mean UVF/AC at enrolment was 6.4 ± 2.6 mL/min/cm, and 35 (9.6%) cases were affected by severely stunted fetal growth. Severely stunted fetal growth was associated with a lower mean UVF/AC (5.4 ± 2.6 vs 6.5 ± 2.6 mL/min/cm; P = 0.02) and a higher frequency of UVF/AC < 10th percentile (8/35 (22.9%) vs 28/330 (8.5%); P = 0.01). Moreover, UVF/AC showed an area under the receiver-operating-characteristics curve (AUC) of 0.65 (95% CI, 0.55-0.75; P = 0.004) in predicting the occurrence of severely stunted fetal growth, and the optimal cut-off value of UVF/AC for discriminating between normal and severely stunted fetal growth was 7.2 mL/min/cm. This value was associated with a sensitivity and specificity of 0.77 (95% CI, 0.60-0.90) and 0.33 (95% CI, 0.28-0.39), and positive and negative predictive values of 0.11 (95% CI, 0.07-0.15) and 0.93 (95% CI, 0.87-0.97), respectively. Regarding the occurrence of adverse perinatal outcome, this was associated independently with maternal age (adjusted odds ratio (aOR), 0.93 (95% CI, 0.87-0.99); P = 0.04), UVF/AC Z-score (aOR, 0.53 (95% CI, 0.30-0.87); P = 0.01) and augmentation of labor (aOR, 2.69 (95% CI, 1.28-5.69); P = 0.009). UVF/AC showed an AUC of 0.65 (95% CI, 0.56-0.73; P = 0.005) in predicting the occurrence of adverse perinatal outcome, and the optimal cut-off value of UVF/AC for discriminating between normal and adverse perinatal outcome was 6.7 mL/min/cm. This value was associated with a sensitivity and specificity of 0.70 (95% CI, 0.54-0.83) and 0.40 (95% CI, 0.34-0.45), and positive and negative predictive values of 0.14 (95% CI, 0.09-0.19) and 0.91 (95% CI, 0.85-0.95), respectively.

CONCLUSIONS

Our data demonstrate an association between reduced UVF close to term, severely stunted fetal growth and adverse perinatal outcome in a cohort of low-risk pregnant women, with a moderate ability to rule out and a poor ability to rule in either outcome. Further studies are needed to establish whether the assessment of UVF can improve the identification of fetuses at risk of subclinical placental insufficiency and adverse perinatal outcome. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of the cerebroplacental ratio and uterine arteries in low-risk pregnancies in early labour for the prediction of obstetric and neonatal outcomes

BACKGROUND

The evidence-based management of human labor includes the antepartum identification of patients at risk for intrapartum hypoxia. However, available evidence has shown that most of the hypoxic-related complications occur among pregnancies classified at low-risk for intrapartum hypoxia, thus suggesting that the current strategy to identify the pregnancies at risk for intrapartum fetal hypoxia has limited accuracy.

OBJECTIVE

To evaluate the role of the combined assessment of the cerebroplacental ratio (CPR) and uterine arteries (UtA) Doppler in the prediction of obstetric intervention (OI) for suspected intrapartum fetal compromise (IFC) within a cohort of low-risk singleton term pregnancies in early labor.

METHODS

Prospective multicentre observational study conducted across four tertiary Maternity Units between January 2016 and September 2019. Low-risk term pregnancies with spontaneous onset of labor were included. A two-step multivariable model was developed to assess the risk of OI for suspected IFC. The baseline model included antenatal and intrapartum characteristics, while the combined model included antenatal and intrapartum characteristics plus Doppler anomalies such as CPR MoM < 10th percentile and mean UtA Doppler PI MoM ≥ 95th percentile. Predictive performance was determined by receiver-operating characteristics curve analysis.

RESULTS

804 women were included. At logistic regression analysis, CPR MoM < 10th percentile (aOR 1.269, 95 % CI 1.188-1.356, P < 0.001), mean UtA PI MoM ≥ 95th percentile (aOR 1.012, 95 % CI 1.001-1.022, P = 0.04) were independently associated with OI for suspected IFC. At ROC curve analysis, the combined model including antenatal characteristics plus abnormal CPR and mean UtA PI yielded an AUC of 0.78, 95 %CI(0.71-0.85), p < 0.001, which was significantly higher than the baseline model (AUC 0.61, 95 %CI(0.54-0.69), p = 0.007) (p < 0.001). The combined model was associated with a 0.78 (95 % CI 0.67-0.89) sensitivity, 0.68 (95 % CI 0.65-0.72) specificity, 0.15 (95 % CI 0.11-0.19) PPV, and 0.98 (0.96-0.99) NPV, 2.48 (95 % CI 2.07-2.97) LR + and 0.32 (95 % CI 0.19-0.53) LR- for OI due to suspected IFC.

CONCLUSIONS

A predictive model including antenatal and intrapartum characteristics combined with abnormal CPR and mean UtA PI has a good capacity to rule out and a moderate capacity to rule in OI due to IFC, albeit with poor predictive value.

Uterine artery Doppler in early labor and perinatal outcome in low-risk term pregnancy: prospective multicenter study

OBJECTIVE

The prediction of adverse perinatal outcomes in low-risk pregnancies is poor, mainly owing to the lack of reliable biomarkers. Uterine artery (UtA) Doppler is closely associated with placental function and may facilitate the peripartum detection of subclinical placental insufficiency. The objective of this study was to evaluate the association of mean UtA pulsatility index (PI) measured in early labor with obstetric intervention for suspected intrapartum fetal compromise and adverse perinatal outcome in uncomplicated singleton term pregnancies.

METHODS

This was a prospective multicenter observational study conducted across four tertiary maternity units. Low-risk term pregnancies with spontaneous onset of labor were included. The mean UtA-PI was recorded between uterine contractions in women admitted for early labor and converted into multiples of the median (MoM). The primary outcome of the study was the occurrence of obstetric intervention, i.e. Cesarean section or instrumental delivery, for suspected intrapartum fetal compromise. Secondary outcomes were the occurrence of adverse perinatal outcomes, including 5-min Apgar score < 7, low cord arterial pH, raised cord arterial base excess, admission to the neonatal intensive care unit (NICU) and postnatal diagnosis of small-for-gestational-age fetus. Composite adverse perinatal outcome was defined as the occurrence of at least one of the following: acidemia in the umbilical artery, defined as pH < 7.10 and/or base excess > 12 mmol/L, 5-min Apgar score < 7 or admission to the NICU.

RESULTS

Overall, 804 women were included, of whom 40 (5.0%) had abnormal mean UtA-PI MoM. Women who had an obstetric intervention for suspected intrapartum fetal compromise were more frequently nulliparous (72.2% vs 53.6%; P = 0.008), had a higher frequency of increased mean UtA-PI MoM (13.0% vs 4.4%; P = 0.005) and had a longer duration of labor (456 ± 221 vs 371 ± 192 min; P = 0.01). On logistic regression analysis, only increased mean UtA-PI MoM (adjusted odds ratio (aOR), 3.48 (95% CI, 1.43-8.47); P = 0.006) and parity (aOR, 0.45 (95% CI, 0.24-0.86); P = 0.015) were independently associated with obstetric intervention for suspected intrapartum fetal compromise. Increased mean UtA-PI MoM was associated with a sensitivity of 0.13 (95% CI, 0.05-0.25), specificity of 0.96 (95% CI, 0.94-0.97), positive predictive value of 0.18 (95% CI, 0.07-0.33), negative predictive value of 0.94 (95% CI, 0.92-0.95), positive likelihood ratio of 2.95 (95% CI, 1.37-6.35) and negative likelihood ratio of 0.91 (95% CI, 0.82-1.01) for obstetric intervention for suspected intrapartum fetal compromise. Pregnancies with increased mean UtA-PI MoM also showed a higher incidence of birth weight < 10th percentile (20.0% vs 6.7%; P = 0.002), NICU admission (7.5% vs 1.2%; P = 0.001) and composite adverse perinatal outcome (15.0% vs 5.1%; P = 0.008).

CONCLUSION

Our study, conducted in a cohort of low-risk term pregnancies enrolled in early spontaneous labor, showed an independent association between increased mean UtA-PI and obstetric intervention for suspected intrapartum fetal compromise, albeit with moderate capacity to rule in, and poor capacity to rule out, this condition. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Maternal, obstetric, and fetal Doppler characteristics in a high-risk population: prediction of adverse perinatal outcomes and of cesarean section due to intrapartum fetal compromise

Objective

To evaluate the capacity of fetal Doppler, maternal, and obstetric characteristics for the prediction of cesarean section due to intrapartum fetal compromise (IFC), a 5-min Apgar score < 7, and an adverse perinatal outcome (APO), in a high-risk population.

Materials and Methods

This was a prospective cohort study involving 613 singleton pregnant women, admitted for labor induction or at the beginning of spontaneous labor, who underwent Doppler ultrasound within the last 72 h before delivery. The outcome measures were cesarean section due to IFC, a 5-min Apgar score < 7, and any APO.

Results

We found that maternal characteristics were neither associated with nor predictors of an APO. Abnormal umbilical artery (UA) resistance index (RI) and the need for intrauterine resuscitation were found to be significant risk factors for cesarean section due to IFC (p = 0.03 and p < 0.0001, respectively). A UA RI > the 95th percentile and a cerebroplacental ratio (CPR) < 0.98 were also found to be predictors of cesarean section due to IFC. Gestational age and a UA RI > 0.84 were found to be predictors of a 5-min Apgar score < 7 for newborns at < 29 and ≥ 29 weeks, respectively. The UA RI and CPR presented moderate accuracy in predicting an APO, with areas under the ROC curve of 0.76 and 0.72, respectively.

Conclusion

A high UA RI appears to be a significant predictor of an APO. The CPR seems to be predictive of cesarean section due to IFC and of an APO in late preterm and term newborns.

The sonopartogram

The assessment of labor progress from digital vaginal examination has remained largely unchanged for at least a century, despite the current major advances in maternal and perinatal care. Although inconsistently reproducible, the findings from digital vaginal examination are customarily plotted manually on a partogram, which is composed of a graphical representation of labor, together with maternal and fetal observations. The partogram has been developed to aid recognition of failure to labor progress and guide management-specific obstetrical intervention. In the last decade, the use of ultrasound in the delivery room has increased with the advent of more powerful, portable ultrasound machines that have become more readily available for use. Although ultrasound in intrapartum practice is predominantly used for acute management, an ultrasound-based partogram, a sonopartogram, might represent an objective tool for the graphical representation of labor. Demonstrating greater accuracy for fetal head position and more objectivity in the assessment of fetal head station, it could be considered complementary to traditional clinical assessment. The development of the sonopartogram concept would require further undertaking of serial measurements. Advocates of ultrasound will concede that its use has yet to demonstrate a difference in obstetrical and neonatal morbidity in the context of the management of labor and delivery. Taking a step beyond the descriptive graphical representation of labor progress is the question of whether a specific combination of clinical and demographic parameters might be used to inform knowledge of labor outcomes. Intrapartum cesarean deliveries and deliveries assisted by forceps and vacuum are all associated with a heightened risk of maternal and perinatal adverse outcomes. Although these outcomes cannot be precisely predicted, many known risk factors exist. Malposition and high station of the fetal head, short maternal stature, and other factors, such as caput succedaneum, are all implicated in operative delivery; however, the contribution of individual parameters based on clinical and ultrasound assessments has not been quantified. Individualized risk prediction models, including maternal characteristics and ultrasound findings, are increasingly used in women's health-for example, in preeclampsia or trisomy screening. Similarly, intrapartum cesarean delivery models have been developed with good prognostic ability in specifically selected populations. For intrapartum ultrasound to be of prognostic value, robust, externally validated prediction models for labor outcome would inform delivery management and allow shared decision-making with parents.

How to Reach the Best Ultrasound Performance in the Delivery Room

Ultrasonography is an instrument that is present in the maternal-fetal assessment throughout pregnancy and with widely documented benefits, but its use in intrapartum is becoming increasingly relevant. From the assessment of labor progression to the assessment of placental disorders, ultrasound can be used to correlate with physiological findings and physical examination, as its benefit in the delivery room cannot yet be proven. There are still few professionals with adequate training for its use in the delivery room and for the correct interpretation of data. Thus, this article aims to present a review of the entire applicability of ultrasound in the delivery room, considering the main stages of labor. There is still limited research in evidence-based medicine of its various possible uses in intrapartum, but it is expected that further studies can bring improvements in the quality of maternal and neonatal health during labor.

Maternal cardiovascular function in the prediction of fetal distress in labor: a prospective cohort study

OBJECTIVE

To explore the strength of association and the diagnostic accuracy of maternal hemodynamic parameters detected noninvasively in predicting an adverse perinatal outcome in labor.

METHODS

Prospective cohort study of singleton women undergoing antepartum care at 37-39 weeks of gestation. A noninvasive ultrasonic cardiac output monitor (USCOM®) was used for cardiovascular assessment. The study outcome was a composite score of adverse perinatal outcome, which included at least one of the following variables: Cesarean or instrumental delivery for abnormal fetal heart monitoring, umbilical artery pH <7.10 or admission to neonatal special care unit. Attending clinicians were blinded to maternal cardiovascular indices. Multivariate logistic regression and area under the curve (AUC) analyses were used to test the diagnostic accuracy of different maternal and ultrasound characteristics in predicting adverse perinatal outcome.

RESULTS

A total of 133 women were recruited. The rate of adverse perinatal outcome was 25.6% (34/133). Women who delivered without abnormal perinatal outcome (controls) were more likely to be parous, compared to those who had an adverse perinatal outcome (44.4 vs. 73.5%; p = .005). Control women had significantly lower systemic vascular resistance (SVR) (median, 1166 vs. 1352 dynes × s/cm⁵, p = .023) and SVR index (SVRI) (median, 2168 vs. 2627 dynes × s/cm⁵/m², p = .039) compared to women who had an adverse perinatal outcome. In this latter group the prevalence of SV <50 ml was significantly higher than in the control group (38.2% (13/34) vs. 11.1%, (11/99) p = .0012). At multivariable logistic regression analysis, SVR (aOR 1.307; 95% CI 1.112-2.23), SV <50 ml (aOR 4.70; 95% CI 1.336-12.006) and parity (3.90: 95% CI 1.545-10.334) were the only variables independently associated with adverse perinatal outcome. A model considering only SVR showed an AUC of 0.631. Integration of SVR with SV <50 ml and parity significantly improves the diagnostic performance of SVR alone to predict adverse outcome (AUC 0.732; p = .016).

CONCLUSION

Pre-labor modifications of maternal cardiovascular variables are associated with adverse perinatal outcome. However, their predictive accuracy for perinatal compromise is low, and thus their use as standalone screening test for adverse perinatal outcome in singleton pregnancies at term is not supported.

Association of the Cerebro-Placental Ratio With Adverse Outcomes in Pregnancies Affected by Gestational Diabetes Mellitus

OBJECTIVES

Cerebro-placental ratio (CPR) is a doppler tool contributes to clinical decision-making in pregnancies affected by small for gestational age weight (SGA). Pregnancies affected by gestational diabetes mellitus (GDM) tend to have higher newborn weight, but greater risk of adverse perinatal outcomes. We hypothesized that in GDM-complicated-pregnancies CPR will be associated with adverse perinatal outcomes even in the absence of SGA.

METHODS

This prospective single-center cohort study included non-anomalous singleton pregnancies in women with GDM. Those with pre-pregnancy diabetes mellitus, hypertensive disorder or suspected SGA were excluded. Routine fetal sonographic assessment included CPR-defined as middle cerebral artery pulsatilty index/umbilical artery pulsatilty index. Masked CPR measurement closest to birth was used, classified as >10th (normal) or ≤10th centile (low). Primary outcome was a composite, consisting of stillbirth, Caesarean birth due to abnormal fetal heart rate pattern, 5-minute Apgar <7, cord arterial pH < 7.0, hypoxic ischemic encephalopathy, or NICU admission >24 hours.

RESULTS

Of 281 participants, 24 (8.5%) had low CPR, at a mean gestational age of 36.3 weeks (IQR 34.0-37.4). Birthweight percentile was significantly lower among the low CPR group (35th [IQR 16-31] versus 60th [IQR 31-82]; P = .002). There was no statistically difference in the primary composite outcome between the groups (8.3% versus 7.0%, P = .68). Low CPR was significantly associated with a higher risk of neonatal hypoglycemia (adjusted odds ratio 3.2, 95% CI 1.2-8.3).

CONCLUSION

In pregnancies affected by GDM, CPR ≤10th percentile was not associated with adverse perinatal outcome but was associated with neonatal hypoglycemia.

Fetal growth restriction and stillbirth: Biomarkers for identifying at risk fetuses

Fetal growth restriction (FGR) is a major cause of stillbirth, prematurity and impaired neurodevelopment. Its etiology is multifactorial, but many cases are related to impaired placental development and dysfunction, with reduced nutrient and oxygen supply. The fetus has a remarkable ability to respond to hypoxic challenges and mounts protective adaptations to match growth to reduced nutrient availability. However, with progressive placental dysfunction, chronic hypoxia may progress to a level where fetus can no longer adapt, or there may be superimposed acute hypoxic events. Improving detection and effective monitoring of progression is critical for the management of complicated pregnancies to balance the risk of worsening fetal oxygen deprivation in utero, against the consequences of iatrogenic preterm birth. Current surveillance modalities include frequent fetal Doppler ultrasound, and fetal heart rate monitoring. However, nearly half of FGR cases are not detected in utero, and conventional surveillance does not prevent a high proportion of stillbirths. We review diagnostic challenges and limitations in current screening and monitoring practices and discuss potential ways to better identify FGR, and, critically, to identify the “tipping point” when a chronically hypoxic fetus is at risk of progressive acidosis and stillbirth.

Cerebro-placental and umbilico-cerebral ratios in uncomplicated monochorionic twins: Longitudinal references and comparison with singletons

OBJECTIVES

Monochorionic twins (MC) are at high risk of adverse outcomes and Doppler investigation of umbilical and cerebral flows is mandatory for their surveillance. The cerebro-placental (CPR) and umbilico-cerebral (UCR) ratios are considered non-invasive measures of fetal adaptation to hypoxemia. We aimed to provide longitudinal references for CPR and UCR from 16 to 37 weeks of gestation that are specific for MC twins, and compare these with singleton charts.

METHODS

Longitudinal study of a cohort of consecutive uncomplicated MC twin pregnancies monitored at our unit from 2010 to 2018. The estimated centile curves were obtained estimating the median with fractional polynomials by a multilevel model and the external centiles through the residuals. The comparison with singletons references was made through graphic evaluation.

RESULTS

One-hundred-fifty-two MC pregnancies were included with a median of 10 longitudinal ultrasounds each. References for CPR and UCR in function of gestational age are presented. Compared to singletons, MC twins showed an earlier and greater circulatory redistribution with lower CPR and higher UCR median values.

CONCLUSIONS

MC twin-specific references for CPR and UCR suitable for serial monitoring are presented. The comparison with singleton references demonstrates substantial differences in the hemodynamic balance that must be considered when interpreting findings in MC twins. This article is protected by copyright. All rights reserved.

New Markers for Placental Dysfunction at Term - Potential for More

The remaining placental reserve capacity at term plays a decisive role in the perinatal morbidity of mother and child. Considering advances made in the field of fetal monitoring, the routine examination methods currently used at term or late term may be insufficient to detect subclinical placental dysfunction (PD). The aim of this study is to offer an up-to-date, narrative review of the literature in the context of detecting PD at term using complementary ultrasound markers and biomarkers. Parameters of fetomaternal Doppler ultrasound and fetal cardiac function, as well as (anti-)angiogenic factors in maternal serum are potential PD markers. These may help identify patients that may benefit from an elective, early induction of labor at term, thereby potentially reducing morbidity and mortality. However, their value in terms of the optimal date of delivery must first be determined in randomized controlled trials on a large number of cases.

Cerebroplacental ratio prediction of intrapartum fetal compromise according to the interval to delivery

Objectives To evaluate whether the interval to delivery modifies the predictive accuracy of the cerebroplacental ratio (CPR) for the prediction of cesarean section for intrapartum fetal compromise (CS-IFC), either as a single marker or combined with estimated fetal weight centile (EFWc), type of labor onset (TLO) and other clinical variables. Material and methods This was a multicenter retrospective study of 5193 women with singleton pregnancies who underwent an ultrasound scan at 35+0- 41+0 weeks and gave birth within one month of examination, at any of the participating hospitals in Spain, UK, and Italy. CS-IFC was diagnosed in case of abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH<7.20, requiring urgent cesarean section. The diagnostic ability of CPR in multiples of the median (CPR MoM) was evaluated at different intervals to delivery, alone and combined with EFWc, TLO, and other pregnancy data such as maternal age, maternal body mass index, parity, and fetal sex, for the prediction of CS-IFC by means of ROC curves and logistic regression analysis. Results The predictive ability of CPR MoM for CS-IFC worsened with the interval to delivery. In general, the best prediction was obtained prior to labor, and adding information related with EFWc and TLO [AUC 0.71 (95% CI 0.64-0.79), 0.73 (95% CI 0.66-0.80) and 0.75 (95% CI 0.69-0.81); P<0.0001]. Addition of more clinical data did not improve prediction. In addition, results did not vary when only cases with spontaneous onset of labor were studied. Conclusion CPR MoM prediction of CS-IFC at the end of pregnancy worsens with the interval to delivery. Accordingly, it should be done in the short term and considering EFWc and TLO.

Women's and clinician's acceptability of participation in a hypothetical obstetric randomized controlled trial: a qualitative survey

BACKGROUND

Involving patients and consumers in research design helps ensure relevance for those affected by the problem being investigated and can optimize recruitment to clinical trials. This is particularly important when conducting research involving pregnant women.

AIMS

We investigated women's motivations to participate in a hypothetical randomized control trial (RCT) of a third-trimester screening test for intrapartum fetal compromise (IFC) and adverse perinatal outcomes.

MATERIALS AND METHODS

Women attending for routine antenatal care at a tertiary center were invited to complete a short, anonymized patient acceptability survey. The survey was developed with the assistance of the Perinatal Society of Australia and New Zealand's Consumer Advisory Panel and consisted of Likert scales and open-ended questions. It was designed to ascertain women's responses to research issues, particularly the acceptability of being randomized to a non-revealed arm of a screening test RCT.

RESULTS

100 pregnant women took part; 40% indicated that they would agree/strongly agree to participate in a hypothetical RCT regardless of whether they were given the result of a screening test and 31% were unsure. Randomization to either an intervention or control group was acceptable to 47%, 30% were unsure and 23% were not willing to be randomized. Reasons to participate included the desire to contribute to research and to improve pregnancy care.

CONCLUSIONS

Participation in an RCT of a screening test for IFC involving non-disclosure of the test result was acceptable to a large minority of pregnant women. This finding supports the feasibility of conducting a large-scale study of this design.

Safety Aspects of Perinatal Ultrasound

Ultrasound safety is of particular importance in fetal and neonatal scanning. Fetal tissues are vulnerable and often still developing, the scanning depth may be low, and potential biological effects have been insufficiently investigated. On the other hand, the clinical benefit may be considerable. The perinatal period is probably less vulnerable than the first and second trimesters of pregnancy, and ultrasound is often a safer alternative to other diagnostic imaging modalities. Here we present step-by-step procedures for obtaining clinically relevant images while maintaining ultrasound safety. We briefly discuss the current status of the field of ultrasound safety, with special attention to the safety of novel modalities, safety considerations when ultrasound is employed for research and education, and ultrasound of particularly vulnerable tissues, such as the neonatal lung. This CME is prepared by ECMUS, the safety committee of EFSUMB, with contributions from OB/GYN clinicians with a special interest in ultrasound safety.

Role of umbilicocerebral and cerebroplacental ratios in prediction of perinatal outcome in FGR pregnancies

Purpose

Aim of our study was to compare the prognostic value of the Umbilical-to-Cerebral ratio (UCR) directly to the Cerebroplacental ratio (CPR) in the prediction of poor perinatal outcomes in pregnancies complicated by Fetal Growth Restriction (FGR).

Methods

A retrospective study was carried out on pregnant women with either a small-for-gestational age (SGA) fetus or that were diagnosed with FGR. Doppler measurements of the two subgroups were assessed and the correlation between CPR, UCR and relevant outcome parameters was evaluated by performing linear regression analysis, binary logistic analysis and receiver operator characteristic (ROC) curves. Outcomes of interest were mode of delivery, acidosis, preterm delivery, gestational age at birth as well as birthweight and centiles.

Results

Boxplots and Scatterplots illustrated the different distribution of CPR and UCR leading to deviant correlational relationships with adverse outcome parameters. In almost all parameters examined, UCR showed a higher independent association with preterm delivery (OR: 5.85, CI 2.23–15.34), APGAR score < 7 (OR: 3.52; CI 1.58–7.85) as well as weight under 10th centile (OR: 2.04; CI 0.97–4.28) in binary logistic regression compared to CPR which was only associated with preterm delivery (OR: 0.38; CI 0.22–0.66) and APGAR score < 7 (OR: 0.27; CI 0.06–1.13). When combined with different ultrasound parameters in order to differentiate between SGA and FGR during pregnancy, odds ratios for UCR were highly significant compared to odds ratios for CPR (OR: 0.065, 0.168–0.901; p = 0.027; OR: 0.810, 0.369–1.781; p = 0.601). ROC curves plotted for CPR and UCR showed almost identical moderate prediction performance.

Conclusion

Since UCR is a better discriminator of Doppler values in abnormal range it presents a viable option to Doppler parameters and ratios that are used in clinical practice. UCR and CPR showed equal prognostic accuracy conserning sensitivity and specificity for adverse perinatal outcome, while adding UA PI and GA_scan increased prognostic accuracy regarding negative outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00404-021-06268-4.

Middle Cerebral Artery-to-Uterine Artery Pulsatility Index Ratio and Cerebroplacental Ratio Independently Predict Adverse Perinatal Outcomes in Pregnancies at Term

This study aimed to investigate potential predictors, including the cerebroplacental ratio and the middle cerebral artery (MCA)-uterine artery pulsatility index (PI) ratio, for adverse perinatal outcomes in pregnancies at term. This was an observational, prospective study of recruited pregnancies at term. The data were extracted from the medical records in hospital. An adverse perinatal outcome was set as the primary observational endpoint. The receiver operating characteristic curve was plotted to investigate the predictive and cutoff values of risk factors for adverse perinatal outcomes. Univariate and multivariate logistic regression analyses evaluated independent risk factors (maternal, neonatal, prenatal ultrasound and Doppler variables) for adverse perinatal outcomes. There were 392 pregnancies at term included in the study, with 19.4% experiencing adverse perinatal outcomes. The MCA-uterine artery PI ratio was a good predictor of adverse perinatal outcomes by receiver operating characteristic curve analysis (area under the curve = 0.886, p < 0.001), and the cerebroplacental ratio (odds ratio, 0.42; 95% confidence interval, 0.20-0.93; p = 0.032) and MCA-uterine artery PI ratio (odds ratio, 0.25; 95% confidence interval, 0.16-0.42; p = 0.032) were two independent risk factors for adverse perinatal outcomes by univariate and multivariate logistic regression analyses. Notably, both MCA-uterine artery PI ratio and cerebroplacental ratio are significant predictors of adverse perinatal outcome in pregnancies at term.

Cerebroplacental doppler ratio and perinatal outcome in late-onset foetal growth restriction

The purpose of this study was to determine whether gestational age-specific levels of the cerebroplacental ratio (CPR) as a third-trimester ultrasound marker has benefits in the prediction of perinatal morbidity and mortality on foetuses with late-onset foetal growth restriction (FGR). A retrospective study of singleton pregnancies diagnosed with late-onset FGR was performed. Of 407 pregnancies meeting our inclusion criteria, 313 had normal (Group 1) and 94 had abnormal CPR (Group 2). Both groups were similar in age, gestational age at diagnosis, body mass index and parity. There was a significant association between the presence of oligohydramnios and abnormal CPR. Mean gestational age at delivery and mean neonatal birth weight were significantly lower in Group 2. Neonatal intensive care unit admission, foetal distress, low 5-minute Apgar score <7, and low cord pH < 7.1 rates were significantly higher in Group 2. There was one neonatal death in both groups. Multivariable regression analysis demonstrated that, in the prediction of APO, there was a significant contribution from neonatal birth weight <10th percentile, CPR <5th percentile and oligohydramniosis. Our findings revealed that CPR value less than 5th centile can be used as a predictor of APO in late-onset FGR.IMPACT STATEMENTWhat is already known on this subject? Low cerebroplacetal ratio (CPR) is a marker of failure to reach the growth potential regardless of foetal weight.What do the results of this study add? The CPR can be used as an adequate predictor of adverse perinatal outcome in pregnancies with late-onset foetal growth restriction.What are the implications of these findings for clinical practice and/or further research? Routine calculation and report of CPR during basic ultrasound examination may help to identify foetuses with FR with a higher risk of adverse perinatal outcome. Future prospective studies on pregnancies with FGR with oligohydroamnios or normal amniotic fluid volume should focus on determining CPR threshold.

Prelabor and intrapartum Doppler ultrasound to predict fetal compromise

According to current estimates, over 20% of the 4 million neonatal deaths occurring globally every year are related to intrapartum hypoxic complications that happen as a result of uterine contractions against a background of inadequate placental function. Most of such intrapartum complications occur among apparently uncomplicated term pregnancies. Available evidence suggests that current risk-assessment strategies do not adequately identify many of the fetuses vulnerable to periods of intermittent hypoxia that characterize human labor. In this review, we discuss the data available on Doppler ultrasound for the evaluation of placental function before and during labor in appropriately grown fetuses; we also discuss the current strategies for ultrasound-based risk stratification, the physiology of intrapartum compromise, and the potential future treatments to prevent fetal distress in labor and reduce perinatal complications related to birth asphyxia.

The Diagnostic Ability of the Cerebroplacental Ratio for the Prediction of Adverse Perinatal Outcome and Intrapartum Fetal Compromise within One Day of Delivery

OBJECTIVES

The objectives of this study were to evaluate the diagnostic abilities of the cerebroplacental ratio (CPR) for the prediction of adverse perinatal outcome (APO) and cesarean section for intrapartum fetal compromise (CS-IFC) within 1 day of delivery.

DESIGN

Retrospective observational case-control study.

METHODS

This was a study of 254 high-risk fetuses attending the day hospital unit of a tertiary referral hospital that underwent an ultrasound examination at 32-41 weeks and gave birth within 1 day of examination. APO was defined as a composite of abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH <7.20 requiring urgent cesarean section, neonatal umbilical cord pH <7.10, 5-min Apgar score <7, and postpartum admission to neonatal or pediatric intensive care units. CS-IFC was defined in case of abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH <7.20 requiring urgent cesarean section. The diagnostic ability of CPR for the prediction of APO and CS-IFC was calculated alone and in combination with estimated fetal weight and gestational clinical parameters, including the type of labor onset, using ROC curves and logistic regression analysis.

RESULTS

CPR in multiples of the median (MoM) was a moderate predictor of APO (area under the curve [AUC] = 0.77, p < 0.0001) and CS-IFC (AUC = 0.82, p < 0.0001). The predictive abilities of the multivariable model for APO (AUC = 0.81, p < 0.0001) and CS-IFC (AUC = 0.82, p < 0.0001) did not differ from those of CPR alone .

LIMITATIONS

The small number of cases and the scarcity of information concerning labor induction.

CONCLUSION

In high-risk pregnancies, CPR MoM is a moderate predictor of APO and CS-IFC when performed within 24 h of delivery.

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.

Monitoring fetal well-being in labor in late fetal growth restriction

Late-onset fetal growth restriction (FGR) accounts for approximately 70-80% of all cases of FGR secondary to uteroplacental insufficiency. It is associated with an increased incidence of adverse antepartum and perinatal events, which in most instances result from hypoxic insults either present at the onset of labor or supervening during labor as a result of uterine contractions. Labor represents a stressful event for the fetoplacental unit being uterine contractions associated with an up-to 60% reduction of the uteroplacental perfusion. Intrapartum fetal heart rate monitoring by means of cardiotocography (CTG) currently represents the mainstay for the identification of fetal hypoxia during labor and is recommended for the fetal surveillance during labor in the case of FGR or other conditions associated with an increased risk of intrapartum hypoxia. In this review we discuss the potential implications of an impaired placental function on the intrapartum adaptation to the hypoxic stress and the role of the CTG and alternative techniques for the intrapartum monitoring of the fetal wellbeing in the context of FGR secondary to uteroplacental insufficiency.

Reference values for pulsatility index of fetal anterior and posterior cerebral arteries in prolonged pregnancy

OBJECTIVE

To establish consistent normal reference values for fetal anterior cerebral artery (ACA) and posterior cerebral artery (PCA) pulsatility index (PI) in prolonged pregnancy.

METHODS

This prospective cross-sectional observational study included singleton normal prolonged pregnancies into two study groups according to the gestational age: from 40 + 0 to 40 + 6 and from 41 + 0 to 41 + 6 weeks. The PI was assessed in both anatomical segments of ACA (ACA-S1 and ACA-S2) and of PCA (PCA-S1 and PCA-S2) with color Doppler imaging and pulsed Doppler examination, and reference centiles charts were generated. PI values from the two investigated segments of each vessel were also compared.

RESULTS

Data were obtained in 771 patients: n = 448 in the 40 + 0 and 40 + 6 weeks group, and n = 323 in the 41 + 0 and 41 + 6 weeks group. A moderate decrease in PI was observed as pregnancy progressed. No differences in PI values were found between the two anatomical segments of ACA and PCA.

CONCLUSION

This study provides Doppler reference values for the fetal ACA and PCA PI. It also shows that Doppler examination could be performed indifferently in one of the two anatomical segments of these arteries.

Intrapartum Doppler ultrasound: where are we now?

Intrapartum hypoxic events most commonly occur in low-risk pregnancies with appropriately grown fetuses. Continuous intrapartum monitoring by means of cardiotocography has not demonstrated a reduction in the frequency of adverse perinatal outcome but has been linked with an increase in the caesarean section rate, particularly among women considered at low risk. Available data from the literature suggests that abnormalities in the uterine artery Doppler and in the ratio between fetal cerebral and umbilical Doppler (i.e. cerebroplacental ratio [CPR]) are associated with conditions of subclinical placental function occurring in fetuses who have failed to achieve their growth potential regardless of their actual size. In this review we summarize the available evidence on the use of intrapartum Doppler ultrasound for the fetal surveillance during labor and the identification of the fetuses at risk of intrapartum distress.

The role of abnormal cerebroplacental ratio in predicting adverse fetal outcome in pregnancies with scheduled induction of labor

OBJECTIVE

To investigate the role of abnormal cerebroplacental ratio (CPR) in predicting adverse fetal outcome in pregnancies with induction of labor.

METHODS

This prospective observational study conducted at Medeniyet University Göztepe Training and Research Hospital between December 1, 2018 and October 31, 2019 enrolled women with scheduled induction of labor at or beyond 37 weeks of pregnancy. Women with singleton non-anomalous fetuses with cephalic presentation and who had Bishop scores of 5 or less in pelvic examination were included in the study. Exclusion criteria were the presence of uterine scar history, non-cephalic presentation, multiple pregnancy, vacuum- or forceps-assisted delivery, and shoulder dystocia. Using fetal Doppler ultrasound, CPR was calculated (the ratio of umbilical artery to middle cerebral artery pulsatility index) and categorized into abnormal CPR (<1) and normal CPR (≥1). Data on maternal and delivery characteristics, fetal birth weight, and fetal complications were compared between the groups.

RESULTS

A total of 145 women were included, 28 in the abnormal CPR group and 117 in the normal CPR group. Multivariate analysis revealed labor induction at a later week of pregnancy (odds ratio [OR] 10.33, P = 0.001), lack of intrauterine growth restriction (IUGR) (OR 13.21, P = 0.001), fetal distress (OR 8.14, P = 0.003) or meconium aspiration (OR 159.91, P = 0.001), and umbilical artery pH values greater than 7.31 (OR 17.51, P = 0.015) to be associated with an increased likelihood of having normal (≥1) CPR values. Receiver operating characteristic analysis revealed association of normal CPR values with later labor induction (cut-off value of >38.3 weeks, P = 0.001), higher birth weight (cut-off value of >2460 g, P = 0.022) and higher umbilical artery pH (cut-off value of >7.31, P = 0.007).

CONCLUSION

Our findings revealed the significant role of abnormal CPR in predicting adverse fetal outcome in singleton pregnancies with scheduled induction of labor.

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

OBJECTIVE

To predict intrapartum fetal compromise (FC) and admission to neonatal intensive care unit (NICU) by cerebroplacental ratio (CPR) in term pregnancies.

METHODS

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.

RESULTS

Mean interval from US to delivery was 2.21 ± 2.71 days. 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).

CONCLUSION

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.

Could a multidisciplinary regional audit identify avoidable factors and delays that contribute to stillbirths? A retrospective cohort study

Background

The annual rate of stillbirth in Sweden has remained largely unchanged for the past 30 years. In Sweden, there is no national audit system for stillbirths. The aim of the study was to determine if a regional multidisciplinary audit could help in identifying avoidable factors and delays associated with stillbirths.

Methods

Population-based retrospective cohort study.

Settings: Six labour wards in Stockholm County.

Participants: Women delivering a stillbirth > 22 weeks of gestation in Stockholm during 2017.

Intervention: A multidisciplinary team was convened. Each team member independently assessed the medical chart of each case of stillbirth regarding causes and preventability, level of delay, the standard of healthcare provided, the investigation of maternal/foetal diseases and if any recommendations were given for the next pregnancy. A decision was based on the agreement of all five members. If no agreement was reached, a reassessment of the case was done and the medical record was scrutinized again until a mutual decision was made.

Primary outcomes: The frequency of probably/possibly preventable factors associated with a stillbirth and the level of delay (patient/caregiver).

Secondary outcomes: The causes of death, the standard of antenatal/intrapartum/postpartum care, whether a summary of possible causes of the stillbirth was made and if any plans for future pregnancies were noted.

Results

Thirty percent of the stillbirths were assessed as probably/possibly preventable. More frequent ultrasound/clinical check-ups, earlier induction of labour and earlier interventions in line with current guidelines were identified as possibly preventable factors. A possibly preventable stillbirth was more common among non-Swedish-speaking women (p = 0.03). In 15% of the cases, a delay by the healthcare system was identified. Having multiple caregivers, absence of continuity in terms of attending the antenatal clinic and not following the basic monitoring program for antenatal care were also identified as risk factors for a delay.

Conclusion

A national/regional multidisciplinary audit group retrospectively identified factors associated with stillbirth. Access to good translation services or a more innovative approach to the problem regarding communication with mothers could be an important factor to decrease possible patient delays contributing to stillbirths.

Trial registration

NCT04281368.

Changes in fetoplacental Doppler indices following intrapartum maternal sildenafil citrate treatment

OBJECTIVE

Uterine contractions during labour can result in a 60 % decline in fetoplacental perfusion, predisposing the fetus to hypoxic brain injury. Sildenafil citrate (SC) has shown promise in increasing uteroplacental perfusion as well as reducing the risk of operative birth for intrapartum fetal compromise (IFC). The aim of this study was to investigate the effect of intrapartum SC administration on fetoplacental blood flow indices.

METHODS

This was a subgroup analysis from an earlier Phase II double blind randomized controlled trial; assessing the effect of intrapartum SC administration (50 mg orally 8 -hly in labour) compared to placebo for the reduction of operative birth for IFC. An ultrasound scan measuring fetoplacental Doppler indices was performed prior to and 1-4 h after the administration of the first treatment dose.

RESULTS

Of the 300 women randomized to the main study, pre-treatment ultrasound scans were performed in 261 participants who received the study medication; paired pre- and post-treatment scans were performed in 70 (26.8 %). SC resulted in an increase in the middle cerebral artery pulsatility index (PI) z-score [+0.08 (1.35) vs.-0.12 (1.15)], a decline in the umbilical artery-PI z-score [-0.07 (0.96) vs. + 0.04 (1.25)] and an increase in the cerebroplacental ratio [MCA-PI/UA-PI] (CPR) z-score [+0.10 (1.13) vs.-0.26 (1.14)] although these failed to reach statistical significance. Amongst those with a pre-treatment CPR above the 5th centile, SC significantly reduced the risk of operative birth for IFC compared to placebo [logrank p = 0.02; hazards ratio 0.48, 95 % CI 0.29-0.77, p = 0.003].

CONCLUSION

Although the differences in Doppler indices pre- and post- SC treatment were non-significant, there was a clear trend towards a reduction in the UA PI, a corresponding increase in the MCA PI and a rise in post treatment CPR values suggesting potential improvement in fetoplacental Dopplers with intrapartum SC treatment. However this study was limited by the small sample size. The results of this hypothesis generating study suggest that it may be possible to stratify women that would most benefit from this intervention based upon their pre-labour CPR.

Prelabor screening at term using the cerebroplacental ratio and placental growth factor: a pragmatic randomized open-label phase 2 trial

BACKGROUND AND OBJECTIVE

In some women placental function may not be adequate to meet fetal growth requirements in late pregnancy or the additional demands during labor, thus predisposing these infants to intrapartum fetal compromise and subsequent serious morbidity and mortality. The objective of this study was to determine if the introduction of a prelabor screening test at term combining the cerebroplacental ratio and maternal placental growth factor level would result in a reduction in a composite of adverse outcomes.

STUDY DESIGN

Single-site, nonblinded, randomized controlled trial conducted at a tertiary hospital in Brisbane, Australia. Eligible women were randomized to either receive the screening test performed between 37-38 weeks or routine obstetric care. Screen-positive women were offered induction of labor. The primary outcome was a composite of emergency cesarean delivery for nonreassuring fetal status (fetal distress) or severe neonatal acidosis or low Apgar score or stillbirth or neonatal death.

RESULTS

Women were recruited and randomized (n = 501) between April 2017 and January 2019. Sixty-three of 249 subjects (25.3%) in the screened group compared to 56 of 252 (22.2%) in the control group experienced the primary outcome (relative risk = 1.14 [95% confidence interval, 0.83-1.56]; P = .418). Women who screened positive were more likely to require operative delivery for fetal distress, have meconium-stained liquor, have pathologic fetal heart rate abnormalities, and have infants with lower birthweight compared to women that screened negative.

CONCLUSION

The introduction of this test did not result in improvements in intrapartum intervention rates or neonatal outcomes. However, it did show discriminatory potential, and future research should focus on refining the thresholds used.

Comparison between cerebroplacental ratio and umbilicocerebral ratio in predicting adverse perinatal outcome at term

OBJECTIVE

Cerebroplacental ratio (CPR) has been associated with adverse perinatal outcome irrespective of fetal weight. More recently, it has been proposed that the ratio between umbilical and middle cerebral artery pulsatility index, the umbilicocerebral ratio (UCR) had a higher diagnostic accuracy compared to CPR in predicting adverse outcome. The aim of the study was to compare the diagnostic accuracy of CPR and UCR in predicting adverse perinatal outcome in the third trimester of pregnancy.

STUDY DESIGN

Secondary analysis of prospective study carried out in a dedicated research ultrasound clinic in a single tertiary referral center over a one-year period. Inclusion criteria were consecutive singleton pregnancies between 36 + 0 and 37 + 6 weeks of gestation. Exclusion criteria were multiple gestations, pregnancies affected by structural or chromosomal anomalies, maternal medical complications or drugs intake and abnormal Doppler waveform in the UA, defined as PI>95th or absent/end diastolic flow. All women were pre-screened at 28-32 weeks of gestation in order to rule out signs of early fetal growth restriction. The primary outcome was to compare the diagnostic performance of CPR and UCR in detecting the presence of fetuses affected by a composite adverse outcome.

RESULTS

Mean CPR (1.35 ± 0.39 vs 1.85 ± 0.58, p < 0.001) was significantly lower while mean UCR (0.78 ± 0.25 vs 0.58 ± 0.20, p = 0.001) was significantly higher in pregnancies experiencing compared to those not experiencing composite adverse outcome. There was no difference between CPR and UCR in predicting adverse perinatal outcome in the third trimester of pregnancy and both showed a very low diagnostic accuracy. CPR had an AUC of 0.51 (95 % CI 0.43-0.58) while UCR had an AUC of 0.51 (95 % CI 0.43-0.58) in predicting composite adverse outcome. Likewise, there was no difference in the diagnostic accuracy of CRP (AUC: 0.600, 95 % CI 0.36-0.83) and UCR (AUC: 0.589, 95 % CI 0.35-0.83) when considering only SGA fetuses.

CONCLUSIONS

A low CPR and a high UCR are significantly associated with adverse perinatal outcome in singleton pregnancies at term. There was no difference between CPR and UCR in predicting perinatal outcome. Despite this, the diagnostic accuracy of both these parameters is too poor to advocate for their use as a screening tool of perinatal impairment at term, unless specific indications, such as SGA or FGR, have been identified.

Cerebroplacental ratio (CPR) and reduced fetal movement: predicting neonatal outcomes

Objective: The aim of this study was to evaluate the role of cerebroplacental ratio (CPR) in term pregnancies with reduced fetal movements (RFM) and appropriate for gestational age (AGA)fetuses to predict poor neonatal outcomes.Methods: A prospective cohort study was performed on 150 singleton pregnancies with gestational age of 37-41 weeks and multiple episodes of RFM (case group) and 150 pregnancies within the same criteria only without RFM (control group). Both groups had appropriate for gestational age (AGA)fetuses. Umbilical artery (UA) and middle cerebral artery (MCA) pulsatility indices (PI) were measured, and MCA to UA ratio (CPR) was calculated. Doppler indices and neonatal outcomes were compared between the two groups. Independent prediction role of CPR MoM was evaluated through a binary logistic regression method.Results: The RFM group had significantly higher UA- PI MoM (1.01 ± 0.19 versus 0.86 ± 0.05, p < .001), lower MCA MoM (1.28 ± 0.20 versus 1.40 ± 0.13, (p < .001)) and lower CPR MoM (0.98 ± 0.24 versus 1.23 ± 0.12, (p < .001)) compared to the control group. Mean umbilical artery pH was lower in the RFM group and the frequency of neonatal UA cord pH <7.2 was higher in the RFM group. In RFM group, CPR MoM showed a significant linear correlation with birth weight centiles (r = 0.244, p = .003), umbilical artery pH (r = 0.319, p < .001) and Apgar score at minute 1 (r = 0.332, p < .001). CPR MoM exhibited negative correlation with duration of NICU stay (r= -0.187, p = .022). No similar correlation was observed in the control group. In binary logistic regression analysis, CPR MoM was adjusted for the results of NST; and it was concluded that CPR MoM was the only significant predictor of Apgar score minute 1 = <7 (OR: 0.004; 95% CI: 0.0002-0.0673, p < .001), umbilical artery ph <7.2 (OR: 0.019; 95% CI: 0.00005-0.0423, p < .001) and NICU admission (OR: 0.116; 95% CI: 0.018-0.744, p = .023). In multivariate binary logistic regression analysis included parity, history of abortion and ART, AFI, BPP and CPR MoM; the AFI (OR: 0.976; 95% CI: 0.957-0.995, p = .014), BPP (OR: 0.306; 95% CI: 0.172-0.545, p < .001) and CPR MoM (OR: 0.00005 95% CI: 0.000003-0.00061, p < .001) were the significant predictor of RFM. Area under the curve in receiver operating characteristics (ROC) curve was calculated as 0.828 for CPR MoM as a predictor of RFM (SE: 0.024, p < .001), yielding sensitivity and specificity estimates of 80.0% and 65.0%, respectively, using an optimal cutoff level of = < 1.19.Conclusion: This study concluded that reduced fetal movement was significantly related to low CPR MOM. Also, it showed the independent role of CPR MoM for prediction of lower neonatal umbilical artery pH, lower Apgar score minute 1 and higher rate of NICU admission in AGA term fetuses without considering NST results. Also, AFI, BPP and CPR MoM are significant predictors of RFM.

Role of Doppler ultrasound at time of diagnosis of late-onset fetal growth restriction in predicting adverse perinatal outcome: prospective cohort study

OBJECTIVE

Pregnancies complicated by late-onset fetal growth restriction (FGR) are at increased risk of short- and long-term morbidities. Despite this, identification of cases at higher risk of adverse perinatal outcome, at the time of FGR diagnosis, is challenging. The aims of this study were to elucidate the strength of association between fetoplacental Doppler indices at the time of diagnosis of late-onset FGR and adverse perinatal outcome, and to determine their predictive accuracy.

METHODS

This was a prospective study of consecutive singleton pregnancies complicated by late-onset FGR. Late-onset FGR was defined as estimated fetal weight (EFW) or abdominal circumference (AC) < 3^rd centile, or EFW or AC < 10^th centile and umbilical artery (UA) pulsatility index (PI) > 95^th centile or cerebroplacental ratio (CPR) < 5^th centile, diagnosed after 32 weeks. EFW, uterine artery PI, UA-PI, fetal middle cerebral artery (MCA) PI, CPR and umbilical vein blood flow normalized for fetal abdominal circumference (UVBF/AC) were recorded at the time of the diagnosis of FGR. Doppler variables were expressed as Z-scores for gestational age. Composite adverse perinatal outcome was defined as the occurrence of at least one of emergency Cesarean section for fetal distress, 5-min Apgar score < 7, umbilical artery pH < 7.10 and neonatal admission to the special care unit. Logistic regression analysis was used to elucidate the strength of association between different ultrasound parameters and composite adverse perinatal outcome, and receiver-operating-characteristics (ROC)-curve analysis was used to determine their predictive accuracy.

RESULTS

In total, 243 consecutive singleton pregnancies complicated by late-onset FGR were included. Composite adverse perinatal outcome occurred in 32.5% (95% CI, 26.7-38.8%) of cases. In pregnancies with composite adverse perinatal outcome, compared with those without, mean uterine artery PI Z-score (2.23 ± 1.34 vs 1.88 ± 0.89, P = 0.02) was higher, while Z-scores of UVBF/AC (-1.93 ± 0.88 vs -0.89 ± 0.94, P ≤ 0.0001), MCA-PI (-1.56 ± 0.93 vs -1.22 ± 0.84, P = 0.004) and CPR (-1.89 ± 1.12 vs -1.44 ± 1.02, P = 0.002) were lower. On multivariable logistic regression analysis, Z-scores of mean uterine artery PI (P = 0.04), CPR (P = 0.002) and UVBF/AC (P = 0.001) were associated independently with composite adverse perinatal outcome. UVBF/AC Z-score had an area under the ROC curve (AUC) of 0.723 (95% CI, 0.64-0.80) for composite adverse perinatal outcome, demonstrating better accuracy than that of mean uterine artery PI Z-score (AUC, 0.593; 95% CI, 0.50-0.69) and CPR Z-score (AUC, 0.615; 95% CI, 0.52-0.71). A multiparametric prediction model including Z-scores of MCA-PI, uterine artery PI and UVBF/AC had an AUC of 0.745 (95% CI, 0.66-0.83) for the prediction of composite adverse perinatal outcome.

CONCLUSION

While CPR and uterine artery PI assessed at the time of diagnosis are associated independently with composite adverse perinatal outcome in pregnancies complicated by late-onset FGR, their diagnostic performance for composite adverse perinatal outcome is low. UVBF/AC showed better accuracy for prediction of composite adverse perinatal outcome, although its usefulness in clinical practice as a standalone predictor of adverse pregnancy outcome requires further research. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Association between the fetal cerebroplacental ratio and biomarkers of hypoxia and angiogenesis in the maternal circulation at term

OBJECTIVES

A low fetal cerebroplacental ratio (CPR) in late pregnancy is a marker of a fetus that has failed to reach its growth potential and is associated with a variety of perinatal and pregnancy complications. It is not known if it is also correlated with aberrations in angiogenic, hypoxia-responsive or inflammatory cytokine levels in the maternal circulation. We investigated if there were any differences in levels of biomarkers of angiogenesis, endothelial cell dysfunction, hypoxia and/or inflammation in term pregnancies with a low fetal CPR compared to controls. We hypothesized that as the CPR is a marker of suboptimal growth, this would be reflected in a shift towards upregulation of hypoxia-responsive factors even in non-small for gestational age fetuses.

STUDY DESIGN

We used Multiplex ELISA to measure a panel of 28 candidate biomarkers of angiogenesis and/or hypoxia in pre-labour maternal plasma from 113 women at term, stratified for CPR <10th centile vs. CPR >10th centile. Plasma levels of the biomarkers were measured using 2 multiplex Luminex assays - a commercially available human angiogenesis/growth factor panel (R&D Systems®), comprising 15 analytes and an in-house custom panel of a further 13 candidate biomarkers.

RESULTS

Of the 28 candidate biomarkers investigated, we found significantly elevated levels of Carbonic Anhydrase 9 and soluble Fms-like tyrosine kinase (Vascular Endothelial Growth Factor Receptor 1), and lower levels of Placental Growth Factor in plasma from women with a low fetal CPR. The soluble Fms-like tyrosine kinase-1/Placental Growth Factor ratio was also markedly elevated in this cohort. We also demonstrated significant inverse correlations between the fetal CPR and Carbonic Anydrase 9, soluble Fms-like tyrosine kinase and Hepatocyte Growth Factor.

CONCLUSIONS

A low fetal CPR is associated with changes in some hypoxia-responsive and angiogenesis factors in the maternal circulation in pregnancies with normally grown fetuses.

Ultrasound in labor admission to predict need for emergency cesarean section: a prospective, blinded cohort study

OBJECTIVE

To assess whether assessment with ultrasound could improve the detection of emergency cesarean section (ECS) in laboring women.

METHODS

Women who presented with symptoms of active labor or women in need of labor induction were invited to participate in the study. Women included in the study were evaluated with ultrasonography for fetal biometry and vaginal examinations for Bishop score assessment. The main aim in this study was determining factors associated with ECS due to fetal distress and obstructed labor.

RESULTS

No fetal biometry variable was associated with ECS due to any indication (fetal distress and obstructed labor combined) in the univariate analysis. In multivariate analyses, biometry variables were adjusted for Bishop score at admission and only abdominal circumference percentile showed a significant association with the odds of ECS due to any indication (OR:1.02, 95% CI: 1.01-1.03). Biparietal diameter and abdominal circumference variables were associated with the odds of ECS due to obstructed labor in both univariate and multivariate analyses (p < .05 for all). However, the predictive accuracy of biparietal diameter percentile (area under the curve (AUC): 0.55, 95% CI: 0.46-0.63) and abdominal circumference percentile (AUC: 0.56, 95% CI: 0.48-0.64) without adjunct variables were poor. Moreover, the addition of fetal biometry parameters to Bishop score did not improve the predictive accuracy of Bishop score.

CONCLUSION

Ultrasound assessment at admission, in addition to Bishop score assessment, did not significantly improve the prediction of ECS. Also, the fetal biometry alone had poor predictive capability for ECS. Routine ultrasound assessment at labor admission appears to be ineffective for predicting ECS.PrecisFetal biparietal diameter and abdominal circumference showed an association with emergency cesarean due to obstructed labor but the predictive accuracy of fetal biometry was low. Routine ultrasound examination at admission, in addition to Bishop score assessment, may not useful for assessing the risk of emergency section in unselected populations.

Longitudinal change in cerebroplacental ratio in small-for-gestational-age fetuses and risk of stillbirth

OBJECTIVE

To investigate whether assessment of longitudinal change in Doppler variables in small-for-gestational-age (SGA) fetuses improves the prediction of those at risk of stillbirth.

METHODS

This was a longitudinal study of two cohorts of singleton pregnancies, which included SGA and appropriate-for-gestational-age (AGA) fetuses, respectively. The inclusion criteria for the SGA cohort were singleton pregnancy at ≥ 20 weeks' gestation, classified as SGA (estimated fetal weight < 10^th centile). The AGA cohort consisted of singleton pregnancies deemed at high risk of being SGA, which were followed up longitudinally but remained AGA. Fetal middle cerebral artery (MCA) pulsatility index (PI) and umbilical artery (UA)-PI were measured longitudinally and cerebroplacental ratio (CPR) was calculated, and values were converted to multiples of the median. The last two measurements prior to delivery were included in the analysis. Longitudinal models for Doppler variables were developed using linear-mixed models and their accuracy in the prediction of stillbirth was tested using generalized linear models. A Bayesian framework was employed to compare the accuracy of longitudinal and standard (last-scan measurement) models.

RESULTS

In total, 1549 AGA and 941 SGA pregnancies were included in the analysis. There were 30 (3.2%) and no stillbirth cases in the SGA and AGA groups, respectively. Change in MCA-PI, UA-PI and CPR with advancing gestation was significantly different between liveborn AGA and SGA fetuses, with a less pronounced difference with advancing gestation. Using the last measurement, the best models for the prediction of stillbirth in SGA pregnancies were those based on CPR (accuracy, 75.0%; 95% CI, 72.6-77.2%) and UA-PI (accuracy, 71.0%; 95% CI, 68.6-73.4%). The posterior probability of the standard CPR model having a higher accuracy compared with the UA-PI model was 97.2% (magnitude of change (MC), 3.9%; 95% credible interval (CrI), 0.5-7.3%). The accuracies of the standard, compared with the longitudinal, models for UA-PI (71.0% vs 72.8%), MCA-PI (64.6% vs 63.8%) and CPR (75.0% vs 74.9%) in the prediction of stillbirth were not significantly different. The posterior probabilities for improvement in accuracy using longitudinal, compared with standard, assessment were 50.1% (MC, < 0.1%; 95% CrI, -3.3 to 3.3%), 35.2% (MC, -0.1%; 95% CrI, -4.5 to 2.8%) and 82.2% (MC, 1.9%; 95% CrI, -1.5 to 5.3%) for CPR, MCA-PI and UA-PI models, respectively. Therefore, change in Doppler parameters did not improve the accuracy of the prediction of stillbirth, compared with that of the last-scan measurement.

CONCLUSION

Longitudinal assessment of Doppler parameters was not useful in improving the detection of stillbirth in SGA pregnancies, as compared with a single-point assessment. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cross-validated prediction model for severe adverse neonatal outcomes in a term, non-anomalous, singleton cohort

OBJECTIVE

The aim of this study was to develop a predictive model using maternal, intrapartum and ultrasound variables for a composite of severe adverse neonatal outcomes (SANO) in term infants.

DESIGN

Prospectively collected observational study. Mixed effects generalised linear models were used for modelling. Internal validation was performed using the K-fold cross-validation technique.

SETTING

This was a study of women that birthed at the Mater Mother's Hospital in Brisbane, Australia between January 2010 and April 2017.

PATIENTS

We included all term, non-anomalous singleton pregnancies that had an ultrasound performed between 36 and 38 weeks gestation and had recordings for the umbilical artery pulsatility index, middle cerebral artery pulsatility index and the estimated fetal weight (EFW).

MAIN OUTCOME MEASURES

The components of the SANO were: severe acidosis arterial, admission to the neonatal intensive care unit, Apgar score of ≤3 at 5 min or perinatal death.

RESULTS

There were 5439 women identified during the study period that met the inclusion criteria, with 11.7% of this cohort having SANO. The final generalised linear mixed model consisted of the following variables: maternal ethnicity, socioeconomic score, nulliparity, induction of labour, method of birth and z-scores for EFW and cerebroplacental ratio. The final model had an area under the receiver operating characteristic curve of 0.71.

CONCLUSIONS

The results of this study demonstrate it is possible to predict infants that are at risk of SANO at term with moderate accuracy using a combination of maternal, intrapartum and ultrasound variables. Cross-validation analysis suggests a high calibration of the model.