Using cerebroplacental ratio in non-SGA fetuses to predict adverse perinatal outcome: caution is required

The role of the cerebro-placental-uterine ratio in predicting composite adverse perinatal outcomes in patients with pregnancy-induced hypertension

OBJECTIVES

To examine the role of the cerebro-placental-uterine ratio (CPUR) in predicting composite adverse perinatal outcomes (CAPO) in patients with pregnancy-induced hypertension (PIH).

STUDY DESIGN

This prospective, case-control study was conducted at a tertiary hospital with 110 cases of PIH, including 70 patients with preeclampsia and 40 with gestational hypertension, and 110 healthy controls. The middle cerebral artery pulsatility index (MCA-PI), umbilical artery pulsatility index (UA-PI), and uterine artery pulsatility index (UtA-PI) were measured, and the cerebro-placental ratio (CPR=MCA-PI/UA-PI) and CPUR (CPR/UtA-PI) were calculated.

MAIN OUTCOME MEASURE

The role of CPUR in predicting CAPO in preeclampsia and gestational hypertension.

RESULTS

The CPR and CPUR values were lower in the PIH group compared to the control group (p < 0.001). CAPO had a negative correlation with CPR and CPUR (p < 0.001). Univariate regression analysis revealed that the likelihood of CAPO was increased four times by a low CPR value and six times by a low CPUR value. In the ROC analysis, the optimal cut-off value of CPR in predicting CAPO was 1.33 with 74 % sensitivity and 66 % specificity (area under the curve [AUC] = 0.778; p < 0.001) in PIH. For CPUR, the optimal cut-off value was 1.32, at which 82 % sensitivity and 79 % specificity in predicting CAPO (AUC=0.826; p < 0.001).

CONCLUSION

CPUR was determined to be successful with high sensitivity in predicting adverse perinatal outcomes in the presence of PIH. In addition, CPUR was more effective in predicting CAPO in patients with preeclampsia compared to gestational hypertension. CPUR can be used to predict adverse outcomes in patients with PIH.

Doppler ultrasound of umbilical and middle cerebral artery in third trimester small-for-gestational age fetuses to decide on timing of delivery for suspected fetal growth restriction: A cohort with nested RCT (DRIGITAT)

OBJECTIVE

To assess the association of the umbilicocerebral ratio (UCR) with adverse perinatal outcome in late preterm small-for-gestational age (SGA) fetuses and to investigate the effect on perinatal outcomes of immediate delivery.

DESIGN

Multicentre cohort study with nested randomised controlled trial (RCT).

SETTING

Nineteen secondary and tertiary care centres.

POPULATION

Singleton SGA pregnancies (estimated fetal weight [EFW] or fetal abdominal circumference [FAC] <10th centile) from 32 to 36+6 weeks.

METHODS

Women were classified: (1) RCT-eligible: abnormal UCR twice consecutive and EFW below the 3rd centile at/or below 35 weeks or below the 10th centile at 36 weeks; (2) abnormal UCR once or intermittent; (3) never abnormal UCR. Consenting RCT-eligible patients were randomised for immediate delivery from 34 weeks or expectant management until 37 weeks.

MAIN OUTCOME MEASURES

A composite adverse perinatal outcome (CAPO), defined as perinatal death, birth asphyxia or major neonatal morbidity.

RESULTS

The cohort consisted of 690 women. The study was halted prematurely for low RCT-inclusion rates (n = 40). In the RCT-eligible group, gestational age at delivery, birthweight and birthweight multiple of the median (MoM) (0.66, 95% confidence interval [CI] 0.59-0.72) were significantly lower and the CAPO (n = 50, 44%, p < 0.05) was more frequent. Among patients randomised for immediate delivery there was a near-significant lower birthweight (p = 0.05) and higher CAPO (p = 0.07). EFW MoM, pre-eclampsia, gestational hypertension and Doppler classification were independently associated with the CAPO (area under the curve 0.71, 95% CI 0.67-0.76).

CONCLUSIONS

Perinatal risk was effectively identified by low EFW MoM and UCR. Early delivery of SGA fetuses with an abnormal UCR at 34-36 weeks should only be performed in the context of clinical trials.

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.

Definitions matter: detection rates and perinatal outcome for infants classified prenatally as having late fetal growth restriction using SMFM biometric vs ISUOG/Delphi consensus criteria

OBJECTIVES

Fetal growth restriction (FGR) is often secondary to placental dysfunction and is suspected prenatally based on biometric or circulatory abnormalities detected on ultrasound. The aims of this study were to compare the screening performance of the Society for Maternal-Fetal Medicine (SMFM) biometric criteria (estimated fetal weight (EFW) or abdominal circumference (AC) < 10th centile) with that of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)-endorsed Delphi consensus criteria for late FGR for delivery of a small-for-gestational-age (SGA) infant at term, emergency Cesarean section (CS) for non-reassuring fetal status (NRFS), perinatal mortality and composite severe neonatal morbidity.

METHODS

We classified retrospectively non-anomalous singleton infants as having late FGR (diagnosed ≥ 32 weeks) according to SMFM and ISUOG/Delphi criteria in a cohort of women who had been referred to the Mater Mother's Hospital, Brisbane, Australia and who delivered at term between January 2014 and December 2020. The study outcomes were delivery of a SGA infant (birth weight (BW) < 10th or < 3rd centile), emergency CS for NRFS, perinatal mortality (defined as stillbirth or neonatal death within 28 days of a live birth) and a composite of severe neonatal morbidity. We assessed the screening performance of various ultrasound variables by calculating the sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, false-positive and false-negative rates, positive likelihood ratio (LR+) and negative likelihood ratio.

RESULTS

The SMFM and ISUOG/Delphi consensus criteria collectively classified 1030 cases as having late FGR. Of these, 400 cases were classified by both SMFM and ISUOG/Delphi criteria, whilst 548 cases were classified using only SMFM criteria and 82 cases were classified only by ISUOG/Delphi criteria. Prenatal detection of late FGR by SMFM and ISUOG/Delphi criteria was associated with increased odds of delivery of an infant with BW < 10th centile (SMFM: adjusted odds ratio (aOR), 133.0 (95% CI, 94.7-186.6); ISUOG/Delphi: aOR, 69.5 (95% CI, 49.1-98.2)) or BW < 3rd centile (SMFM: aOR, 348.7 (95% CI, 242.6-501.2); ISUOG/Delphi: aOR, 215.4 (95% CI, 148.4-312.7)). Compared with the SMFM criteria, the ISUOG/Delphi criteria were associated with lower odds (aOR, 0.5 (95% CI, 0.3-0.8)) of predicting a SGA infant with BW < 10th centile, but higher odds of predicting emergency CS for NRFS (aOR, 2.30 (95% CI, 1.14-4.66)) and composite neonatal morbidity (aOR, 1.22 (95% CI, 1.05-1.41)). Both SMFM and ISUOG/Delphi criteria were associated with high LR+, specificity, PPV and NPV for the prediction of infants with BW < 10th and BW < 3rd centile. However, both methods functioned much less efficiently for the prediction of composite severe neonatal morbidity or emergency CS for NRFS, with LR+ < 10. The SMFM biometric criteria alone, particularly AC < 3rd centile, had the highest LR+ values for the prediction of perinatal mortality.

CONCLUSION

Both the SMFM and ISUOG/Delphi criteria had strong screening potential for the detection of infants with BW < 10th or < 3rd centile but not for adverse neonatal outcome. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Evaluación integrada del bienestar en un feto apropiado para la edad gestacional (AGA) e insuficiencia placentaria aguda debido a corioamnionitis histológica: Reporte de caso

Introducción. La insuficiencia vascular útero placentaria aguda es una causa de desenlace fetal adverso en fetos con crecimiento adecuado para la edad gestacional. Caso clínico. Paciente de 24 años, con 37 semanas de edad gestacional acude al Instituto Nacional Materno Perinatal de Lima, Perú, por referir escaso sangrado vía vaginal. En la evaluación clínica, se encontró una PA 90/60 mmHg, altura uterina 32 cm, latidos cardiacos fetales en 152. A la evaluación ecográfica, a 1 hora de la admisión se reportó feto de 2902 gramos (percentil 34 Hadlock), un Perfil Biofísico Fetal 6/8 por movimientos corporales disminuidos, Índice de líquido amniótico 11cm, placenta fúndica posterior grado III, IP Doppler de Arteria Cerebral Media 1.18, IP Doppler de la arteria umbilical 0.56, IP ductus venoso 0.26 e Istmo Aórtico con diástole ausente. La prueba estresante a las 3 horas de la admisión fue reportada en 5 puntos con movimientos fetales disminuidos, variabilidad disminuida y aceleraciones ausentes. Se indicó cesárea de emergencia obteniéndose recién nacido masculino de 2846 gr, talla 47.5 cm, Apgar 8 – 9. Se encontró líquido meconial de aspecto sanguinolento oscuro. Al corte de la placenta, se observó parénquima con infartos vellosos: recientes 10% y antiguos 5%. Vellosidades coriales hipoplásicas con espacios intervellosos amplios e infiltrado inflamatorio agudo en corion y amnios, correspondientes a Corioamnionitis aguda y funisitis aguda en el cordón umbilical. Conclusiones. La vigilancia integrada de fetos AEG permiten detectar a fetos en riesgo de desenlace adverso por una insuficiencia placentaria aguda secundaria a corioamnionitis histológica o subclínica.

Decreased fetal movements-the utility of ultrasound to identify infants at risk and prevent stillbirth is poor

BACKGROUND

Despite a paucity of evidence, it is widely accepted that a perceived reduction in fetal movements is associated with an increased risk of stillbirth and poor obstetrical outcome. Consequently, many international guidelines recommend urgent ultrasound assessment of fetal well-being in women presenting with decreased fetal movements.

OBJECTIVE

This study aimed to compare rates of abnormal ultrasound findings reflective of fetal compromise between women presenting with decreased fetal movements and gestation-matched controls in the third trimester.

STUDY DESIGN

This was a retrospective cohort study performed at the Mater Mothers' Hospital in Brisbane between 2017 and 2020. We undertook propensity score matching analysis comparing abnormal ultrasound parameters in women with singleton, nonanomalous pregnancies presenting with decreased fetal movements after 28 weeks' gestation. The primary outcome was a composite of any abnormal scan parameter: umbilical artery pulsatility index >95th centile, middle cerebral artery pulsatility index <5th centile, cerebroplacental ratio <10th centile, estimated fetal weight <10th centile for gestation, middle cerebral artery peak systolic velocity >1.5 multiples of the median, or deepest vertical pocket of amniotic fluid <2 or >8 cm.

RESULTS

After propensity score matching, the study cohort comprised 1466 cases and 2207 controls. The rate of the primary composite outcome was not significantly different between the 2 cohorts (20.2% vs 21.3%; P=.42). There were 30 new cases of small-for-gestational-age detected in the decreased fetal movements cohort, giving a number needed to scan of 48 in the decreased fetal movements group to detect 1 case of small-for-gestational-age. However, the frequency of the composite outcome was higher (13.0% vs 5.4%) at the final scan before birth in women with multiple decreased fetal movement presentations. Despite this, there was no significant difference in clinical outcomes between the 2 cohorts.

CONCLUSION

Ultrasound abnormalities are not increased in women with decreased fetal movements compared with controls.

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 fetal cerebroplacental ratio in pregnancies complicated by hypertensive disorders of pregnancy

BACKGROUND

Hypertensive disorder in pregnancy is common and the optimal ultrasound surveillance of the fetus in this setting is unclear.

AIM

The aim of this study is to assess the relationship between the fetal cerebroplacental ratio (CPR) and perinatal outcomes in pregnancies complicated by maternal hypertension.

MATERIALS AND METHODS

A retrospective cohort study was performed over ten years at a single centre. All women who had an ultrasound scan between 34 and 37 weeks gestation with a non-anomalous singleton pregnancy were included. The hypertensive cohorts were compared to a non-hypertensive cohort. Each cohort was divided into low CPR for gestational age, or normal/high CPR and these were correlated with intrapartum and perinatal outcomes.

RESULTS

A low CPR in a hypertensive pregnancy is associated with an increased risk of induction of labour, emergency caesarean section and poor perinatal outcome. This significance persists when adjusted for gestational age and birth weight. The diagnosis of pre-eclampsia combined with a low CPR markedly increases the risk of poor perinatal outcome, with 52.6% (P < 0.001) of fetuses in this group having either neonatal intensive care unit admission, respiratory distress, low Apgar score, or acidosis. The odds ratio of a fetus with low CPR in a woman with pre-eclampsia having a poor composite outcome is 4.09 (95% CI: 1.85-9.06).

CONCLUSION

There is an association between low CPR and the perinatal outcomes of pregnancies complicated by a hypertensive disorder. This association appears to be stronger in pregnancies complicated by pre-eclampsia than in other types of hypertensive disorders.

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.

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.

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.

Cerebroplacental ratio in predicting adverse perinatal outcome: a meta-analysis of individual participant data

Objective

To investigate if cerebroplacental ratio (CPR) adds to the predictive value of umbilical artery pulsatility index (UA PI) alone – standard of practice – for adverse perinatal outcome in singleton pregnancies.

Design and setting

Meta‐analysis based on individual participant data (IPD).

Population or sample

Ten centres provided 17 data sets for 21 661 participants, 18 731 of which could be included. Sample sizes per data set ranged from 207 to 9215 individuals. Patient populations varied from uncomplicated to complicated pregnancies.

Methods

In a collaborative, pooled analysis, we compared the prognostic value of combining CPR with UA PI, versus UA PI only and CPR only, with a one‐stage IPD approach. After multiple imputation of missing values, we used multilevel multivariable logistic regression to develop prediction models. We evaluated the classification performance of all models with receiver operating characteristics analysis. We performed subgroup analyses according to gestational age, birthweight centile and estimated fetal weight centile.

Main outcome measures

Composite adverse perinatal outcome, defined as perinatal death, caesarean section for fetal distress or neonatal unit admission.

Results

Adverse outcomes occurred in 3423 (18%) participants. The model with UA PI alone resulted in an area under the curve (AUC) of 0.775 (95% CI 0.709–0.828) and with CPR alone in an AUC of 0.778 (95% CI 0.715–0.831). Addition of CPR to the UA PI model resulted in an increase in the AUC of 0.003 points (0.778, 95% CI 0.714–0.831). These results were consistent across all subgroups.

Conclusions

Cerebroplacental ratio added no predictive value for adverse perinatal outcome beyond UA PI, when assessing singleton pregnancies, irrespective of gestational age or fetal size.

Tweetable abstract

Doppler measurement of cerebroplacental ratio in clinical practice has limited added predictive value to umbilical artery alone.

Doppler measurement of cerebroplacental ratio in clinical practice has limited added predictive value to umbilical artery alone.

The physiology of intrapartum fetal compromise at term

Uterine contractions in labor result in a 60% reduction in uteroplacental perfusion, causing transient fetal and placental hypoxia. A healthy term fetus with a normally developed placenta is able to accommodate this transient hypoxia by activation of the peripheral chemoreflex, resulting in a reduction in oxygen consumption and a centralization of oxygenated blood to critical organs, namely the heart, brain, and adrenals. Providing there is adequate time for placental and fetal reperfusion between contractions, these fetuses will be able to withstand prolonged periods of intermittent hypoxia and avoid severe hypoxic injury. However, there exists a cohort of fetuses in whom abnormal placental development in the first half of pregnancy results in failure of endovascular invasion of the spiral arteries by the cytotrophoblastic cells and inadequate placental angiogenesis. This produces a high-resistance, low-flow circulation predisposing to hypoperfusion, hypoxia, reperfusion injury, and oxidative stress within the placenta. Furthermore, this renders the placenta susceptible to fluctuations and reduction in uteroplacental perfusion in response to external compression and stimuli (as occurs in labor), further reducing fetal capillary perfusion, placing the fetus at risk of inadequate gas/nutrient exchange. This placental dysfunction predisposes the fetus to intrapartum fetal compromise. In the absence of a rare catastrophic event, intrapartum fetal compromise occurs as a gradual process when there is an inability of the fetal heart to respond to the peripheral chemoreflex to maintain cardiac output. This may arise as a consequence of placental dysfunction reducing pre-labor myocardial glycogen stores necessary for anaerobic metabolism or due to an inadequate placental perfusion between contractions to restore fetal oxygen and nutrient exchange. If the hypoxic insult is severe enough and long enough, profound multiorgan injury and even death may occur. This review provides a detailed synopsis of the events that can result in placental dysfunction, how this may predispose to intrapartum fetal hypoxia, and what protective mechanisms are in place to avoid hypoxic injury.

Diagnostic accuracy of Doppler ultrasound in predicting perinatal outcome in pregnancies at term: A prospective longitudinal study

INTRODUCTION

To explore the strength of association and the diagnostic accuracy of umbilical (UA), middle cerebral (MCA), uterine arteries pulsatility index (PI) and the cerebroplacental ratio in predicting an adverse outcome when applied to singleton pregnancies at term.

MATERIAL AND METHODS

Prospective study carried out in a dedicated research ultrasound clinic. Attended clinicians were blinded to Doppler findings. Inclusion criteria were consecutive singleton pregnancies between 36⁺⁰ and 37⁺⁶  weeks of gestation. The primary outcome was a composite score of adverse perinatal outcome. Logistic regression and ROC curve analyses were used to analyze the data.

RESULTS

In all, 600 consecutive singleton pregnancies from 36 weeks of gestation were included in the study. Mean MCA PI (1.1 ± 0.2 vs 1.5 ± 0.4, P < 0.001) and cerebroplacental ratio (1.4 ± 0.4 vs 1.9 ± 0.6, P < 0.001) were lower, whereas uterine arteries PI (0.8 ±0.2 vs 0.7 ±0.3, P = 0.001) was higher in pregnancies experiencing than in those not experiencing composite adverse outcome. Conversely, there was no difference in either UA PI (P = 0.399) or estimated fetal weight centile (P = 0.712) between the two groups, but AC centile was lower in fetuses experiencing composite adverse outcome (45.4 vs 53.2, P = 0.040). At logistic regression analysis, MCA PI (odds ratio [OR] 0.1, 95% CI 0.01-.2, P = 0.001), uterine arteries PI (OR 1.4, 95% CI 1.2-1.6, P = 0.001), abdominal circumference centile (OR 1.12, 95% CI 1.1-1.4, P = 0.001) and gestational age at birth (OR 1.6, 95% CI 1.2-2.1, P = 0.004) were independently associated with composite adverse outcome. Despite this, the diagnostic accuracy of Doppler in predicting adverse pregnancy outcome at term was poor.

CONCLUSIONS

MCA PI and cerebroplacental ratio are associated with adverse perinatal outcome at term. However, their predictive accuracy for perinatal compromise is poor, and thus their use as standalone screening test for adverse perinatal outcome in singleton pregnancies at term is not supported.

Assessment of ventricular contractility in fetuses with an estimated fetal weight less than the tenth centile

OBJECTIVE

To determine whether abnormal global, transverse, and longitudinal ventricular contractility of the heart in fetuses with an estimated fetal weight <10th centile is present, irrespective of Doppler studies of the umbilical artery and cerebroplacental ratio.

STUDY DESIGN

This was a retrospective study of 50 fetuses with an estimated fetal weight <10th centile that were classified based on Doppler results from the pulsatility indices of the umbilical artery and middle cerebral artery, and the calculated cerebroplacental ratio (pulsatility indices of the umbilical artery/middle cerebral artery). Right and left ventricular measurements were categorized into 3 groups: (1) global ventricular contractility (fractional area change), (2) transverse ventricular contractility (24-segment transverse fractional shortening), and (3) basal-apical longitudinal contractility (longitudinal strain, longitudinal displacement fractional shortening, and basal lateral and septal wall annular plane systolic excursion). Z scores for the above measurements were computed for fetuses with an estimated fetal weight <10th centile using the mean and standard deviation derived from normal controls. Ventricular contractility measurements were considered abnormal if their Z score values were <5th centile (z score <-1.65) or >95th centile (Z score >1.65), depending on the specific ventricular measurement.

RESULTS

The average gestational age at the time of the examination was 32 weeks 4 days (standard deviation 3 weeks 4 days). None of the 50 study fetuses demonstrated absent or reverse flow of the umbilical artery Doppler waveform. Eighty-eight percent (44/50) of fetuses had one or more abnormal measurements of cardiac contractility of 1 or both ventricles. Analysis of right ventricular contractility demonstrated 78% (39/50) to have 1 or more abnormal measurements, which were grouped as follows: global contractility 38% (19/50), transverse contractility 66% (33/50); and longitudinal contractility 48% (24/50). Analysis of left ventricular contractility demonstrated 1 or more abnormal measurements in 58% (29/50) that were grouped as follows: global contractility 38% (19/50); transverse contractility 40% (20/50); and longitudinal contractility 40% (20/50). Of the 50 study fetuses, 25 had normal pulsatility index of the umbilical artery and cerebroplacental ratios, 80% of whom had 1 or more abnormalities of right ventricular contractility and 56% of whom had 1 or more abnormalities of left ventricular contractility. Abnormal ventricular contractility for these fetuses was present in all 3 groups of measurements; global, transverse, and longitudinal. Those with an isolated abnormal pulsatility index of the umbilical artery (n=11) had abnormalities of transverse contractility of the right ventricular and global contractility in the left ventricle. When an isolated cerebroplacental ratio abnormality was present, the right ventricle demonstrated abnormal global, transverse, and longitudinal contractility, with the left ventricle only demonstrating abnormalities in transverse contractility. When both the pulsatility index of the umbilical artery and cerebroplacental ratio were abnormal (3/50), transverse and longitudinal contractility measurements were abnormal for both ventricles, as well as abnormal global contractility of the left ventricle.

CONCLUSIONS

High rates of abnormal ventricular contractility were present in fetuses with an estimated fetal weight <10th centile, irrespective of the Doppler findings of the pulsatility index of the umbilical artery, and/or cerebroplacental ratio. Abnormalities of ventricular contractility were more prevalent in transverse measurements than global or longitudinal measurements. Abnormal transverse contractility was more common in the right than the left ventricle. Fetuses with estimated fetal weight less than the 10th centile may be considered to undergo assessment of ventricular contractility, even when Doppler measurements of the pulsatility index of the umbilical artery, and cerebroplacental ratio are normal.

Assessment of reproducibility and repeatability of cerebro-placental ratio

INTRODUCTION

To test the reproducibility and repeatability of the cerebro-placental ratio.

STUDY DESIGN

Pregnant women with a singleton pregnancy and secure dating were invited to participate after 24 weeks of pregnancy. Using recommended technique, umbilical artery PI was measured from the free loop of the umbilical cord and from the fetal end by one examiner in a state of fetal quiescence, generating four measurements per fetus. Fetal middle cerebral artery PI was also obtained. Cerebro-placental ratio (CPR) was calculated as MCA PI/Umbilical artery PI. Variability of the CPR on the two sampling occasions was tested using Pitman test of equality of variance for related samples. The difference between the two sets of CPR measurements was plotted against the mean to generate 95% limits of agreement.

RESULTS

A total of 158 women were recruited. The mean CPR was significantly lower when the umbilical artery PI was obtained at the para-vesical site, than when it in obtained from a free loop (p < 0.001). No significant correlation was seen between gestational age and CPR, when the umbilical artery PI was measured from the para-vesical site (r = -0.079, p = 0.323) or the free loop (r = -0.103, p = 0.198). Total variance of the CPR using the umbilical artery free loop was 0.286, and that using the para-vesical site of the umbilical artery was 0.164. Pitman's test showed that the total variability of CPR at the two sites was significantly different (r = 0.254, p < 0.001). The variability of CPR was significantly lower if the umbilical artery PI measurement was taken at the fetal end than that in the free loop.

CONCLUSION

The mean CPR site was significantly lower when the umbilical artery PI was obtained at the para-vesical than in the free loop. Measurement site for the umbilical artery PI contributes to a significant proportion to the total variability of the cerebro-placental ratio. CPR measurements should include umbilical artery PI measurements at the para-vesical site rather than the free loop of the umbilical cord in order to improve repeatability. Appropriate reference ranges for the interpretation of CPR will be needed.

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.

Emergency caesarean for intrapartum fetal compromise and admission to the neonatal intensive care unit at term is more influenced by fetal weight than the cerebroplacental ratio

Objective: Some studies have suggested that the fetal cerebroplacental ratio (CPR) is an independent predictor of intrapartum fetal compromise and admission to the neonatal intensive care unit (NICU) at term particularly in small for gestational age (SGA) compared to appropriate for gestational age (AGA) infants. The aim of this study was to evaluate the association between the CPR and emergency caesarean for intrapartum fetal compromise (CS IFC) and NICU admission at term after adjusting for estimated fetal weight (EFW) and other confounding factors.Methods: This was a retrospective study of women who birthed at the Mater Mother's Hospital in Brisbane, Australia between for women who birthed between January 2000 and April 2017. The CPR was measured within 2 weeks of birth in women that delivered at term and assessed for correlation with CS IFC and admission to NICU. The study cohort was also stratified into four categories according to EFW and CPR thresholds. Appropriate for gestational age (EFW ≥10th centile) and normal CPR (≥10th centile), AGA and low CPR (<10th centile), SGA (EFW <10th centile) and normal CPR and SGA and low CPR.Results: Both CPR <10th centile (adjusted odds ratio (aOR) 2.60, 95% CI 1.82-3.71, p < .001) and EFW <10th centile (aOR 2.63, 95% CI 1.85-3.74, p < .001) demonstrated significant associations with CS IFC. EFW <10th centile (aOR 2.23, 95% CI 1.61-3.09, p < .001) but not CPR <10th centile (aOR 1.41, 95% CI 0.99-2.01, p = .06) was predictive of NICU admission. When stratified according to EFW and CPR thresholds, SGA had significant odds ratios for CS IFC and NICU admission regardless of CPR status. However, the AGA and low CPR cohort was only at increased risk of CS IFC (aOR 2.09, 95% CI 1.30-3.34, p = .002) but not of admission to NICU.Conclusions: At term, the CPR is an independent risk factor for CS IFC regardless of fetal weight. However, the CPR was only predictive of NICU admission in an SGA cohort. Overall, our findings suggest that fetal size is a more important variable for both CS IFC and NICU admission.