The impact of late pregnancy dating on the detection of fetal growth restriction at term

INTRODUCTION

The inaccuracy of late pregnancy dating is often discussed, and the impact on diagnosis of fetal growth restriction is a concern. However, the magnitude and direction of this effect has not previously been demonstrated. In this study, we aimed to investigate the effect of late pregnancy dating by head circumference on the detection of late onset growth restriction, compared to first trimester crown-rump length dating.

MATERIAL AND METHODS

This was a cohort study of 14 013 pregnancies receiving obstetric care at a tertiary center over a three-year period. Universal scans were performed at 12 weeks, including crown-rump length; at 20 weeks including fetal biometry; and at 36 weeks, where biometry, umbilical artery doppler and cerebroplacental ratio were used to determine the incidence of fetal growth restriction according to the Delphi consensus. For the entire cohort, the gestational age was first calculated using T1 dating; and was then recalculated using head circumference at 20 weeks (T2 dating); and at 36 weeks (T3 dating). The incidence of fetal growth restriction following T2 and T3 dating was compared to T1 dating using four-by-four sensitivity tables.

RESULTS

When the cohort was redated from T1 to T2, the median gestation at delivery changed from 40 + 0 to 40 + 2 weeks (p < 0.001). When the cohort was redated from T1 to T3, the median gestation at delivery changed from 40 + 0 to 40 + 3 weeks (p < 0.001). T2 dating resulted in fetal growth restriction sensitivity of 80.2% with positive predictive value of 78.8% compared to T1 dating. T3 dating resulted in sensitivity of 8.6% and positive predictive value of 27.7%, respectively. The sensitivity of abnormal CPR remained high despite T2 and T3 redating; 98.0% and 89.4%, respectively.

CONCLUSIONS

Although dating at 11-14 weeks is recommended, late pregnancy dating is sometimes inevitable, and this can prolong the estimated due date by an average of two to three days. One in five pregnancies which would be classified as growth restricted if the pregnancy was dated in the first trimester, will be reclassified as nongrowth restricted following dating at 20 weeks, whereas nine out of 10 pregnancies will be reclassified as non-growth restricted with 36-week dating.

Adverse perinatal outcomes are strongly associated with degree of abnormality in uterine artery Doppler pulsatility index

OBJECTIVES

To investigate the association between varying degrees of abnormality in the uterine artery Doppler pulsatility index (UtA-PI) and adverse perinatal outcomes.

METHODS

Prospective study of 33,364 women who gave birth to singleton, non-anomalous babies in Oxford, following universal measurement of UtA-PI in mid-pregnancy. Relative risk ratios for the primary outcomes of extended perinatal mortality and live birth with severe small-for-gestational-age (SGA) were calculated by multinomial logistic regression, for early preterm birth (<34+0) and late preterm/term birth (≥34+0). The risks were also investigated for iatrogenic preterm birth or a composite adverse outcome before 34+0 weeks.

RESULTS

Compared with women with normal UtA-PI, the risk of extended perinatal mortality before 34+0 weeks was higher in women with UtA-PI >90th centile (RRR 4.7, 95% CI 2.7-8.0, p<0.001), but this was not demonstrated in later births. The risk of severe SGA birth was strongly associated with abnormal UtA-PI for both early births (RRR 26.0, 95% CI 11.6-58.2, p<0.001), and later births (RRR 2.3, 95% CI 1.8-2.9, p<0.001). Women with a raised UtA-PI were more likely to undergo early iatrogenic birth (RRR 7.8, 95% CI 5.5-11.2, p<0.001). For each of the outcomes and the composite outcome, the risk increased significantly in association with the degree of abnormality, through the 90th, 90-94th, 95-99th and >99th centiles (ptrend<0.001).

CONCLUSIONS

An elevated UtA-PI is a key predictor of iatrogenic preterm birth, severe SGA and perinatal loss up to 34+0 weeks. It is the 90th centile that should be used, and management should be further tailored to the degree of abnormality, as pregnancies with very raised UtA-PI measurements constitute a group at extreme risk. This article is protected by copyright. All rights reserved.

Early antenatal risk factors for births before arrival: An unmatched case-control study

INTRODUCTION

Birth before arrival is associated with maternal morbidity and neonatal morbidity and mortality. Yet, timely risk stratification remains challenging. Our objective was to identify risk factors for birth before arrival which may be determined at the first antenatal appointment.

MATERIAL AND METHODS

This was an unmatched case-control study involving 37 348 persons who gave birth at a minimum of 22+0 weeks' gestation over a 5-year period from January 2014 to October 2019 (IRAS project ID 222260; REC reference: 17/SC/0374). The setting was a large UK university hospital. Data obtained on maternal characteristics at booking was examined for association with birth before arrival using a stepwise multivariable logistic regression analysis. Data are presented as adjusted odds ratios with 95% confidence intervals. Area under the receiver-operator characteristic curves (C-statistic) were employed to enable discriminant analysis assessing the risk prediction of the booking data on the outcome.

RESULTS

Multivariable analysis identified significant independent predictors of birth before arrival that were detectable at booking: parity, ethnicity, multiple deprivation, employment status, timing of booking, distance from home to the nearest maternity unit, and safeguarding concerns raised at booking by clinical staff. Our model demonstrated good discrimination for birth before arrival; together, the predictors accounted for 77% of the data variance (95% confidence interval 0.74-0.80).

CONCLUSIONS

Information gathered routinely at booking may discriminate individuals at risk for birth before arrival. Better recognition of early factors may enable maternity staff to direct higher-risk women towards specialized care services at an early point in their pregnancy, enabling time for clinical and social interventions.

Perinatal outcome of fetuses predicted to be large-for-gestational age on universal third-trimester ultrasound in non-diabetic pregnancy

OBJECTIVE

To describe the perinatal outcome of fetuses predicted to be large-for-gestational age (LGA) on universal third-trimester ultrasound in non-diabetic pregnancies of women attempting vaginal delivery.

METHODS

This was a prospective population-based cohort study of patients from a single tertiary maternity unit in the UK offering universal third-trimester ultrasound and practicing expectant management of suspected LGA until 41-42 weeks. All women with a singleton pregnancy and an estimated due date between January 2014 and September 2019 were included. Women delivering before 37 weeks, those having a planned Cesarean delivery, those with pre-existing or gestational diabetes, those with fetal abnormalities and those who did not undergo a third-trimester scan were excluded from the assessment of perinatal outcome of cases with LGA predicted on ultrasound after implementation of the universal scan period. Association of LGA on universal third-trimester ultrasound screening and perinatal adverse outcome was assessed, with the exposures of interest being estimated fetal weight (EFW) at the 90th -95th , > 95th and > 99th percentile. The reference group was composed of fetuses with EFW at the 30th -70th percentile. Analysis was performed using multivariate logistic regression. The evaluated adverse perinatal outcomes included a composite outcome of admission to neonatal intensive care unit, Apgar score < 7 at 5 min and arterial cord pH < 7.1 (CAO1) and a composite outcome of stillbirth, neonatal death and hypoxic ischemic encephalopathy (CAO2). Secondary maternal outcomes were induction of labor, mode of delivery, postpartum hemorrhage, shoulder dystocia and obstetric anal sphincter injury.

RESULTS

Cases with EFW > 95th percentile on universal third-trimester scan were at increased risk of CAO1 (adjusted odds ratio (aOR), 2.18 (95% CI, 1.69-2.80)) and CAO2 (aOR, 2.58 (95% CI, 1.05-6.34)). Cases with EFW at the 90th -95th percentile had a less pronounced increase in the risk of CAO1 (aOR, 1.35 (95% CI, 1.02-1.78)) and were not at increased risk of CAO2. All pregnancies with a fetus predicted to be LGA were at increased risk of all of the evaluated secondary maternal outcomes except for obstetric anal sphincter injury. The risk of adverse maternal outcome was typically higher with increasing EFW. Post-hoc exploration of data suggested that shoulder dystocia had a limited contribution to composite adverse perinatal outcomes in LGA cases (population attributable fraction of 10.8% for CAO1 and 29.1% for CAO2).

CONCLUSIONS

Cases with EFW > 95th percentile are at increased risk of severe adverse perinatal outcome, such as death and hypoxic ischemic encephalopathy. These findings should aid antenatal counseling regarding the associated risk and delivery options. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Abnormal umbilical artery pulsatility index in appropriately grown fetuses in the early third trimester: an observational cohort study

OBJECTIVE

The aim of this study was to determine if appropriately grown fetuses (those that are not small-for-gestational-age) with a raised umbilical artery pulsatility index (>95th centile) in the mid third trimester are at increased risk of placental dysfunction and adverse outcome.

METHODS

This is a 5-year retrospective cohort study using routinely collected data. Inclusion criteria were singleton, non-anomalous pregnancies having a growth scan with umbilical artery Doppler velocimetry between 28 + 0 and 33 + 6 weeks' gestation. Small-for-gestational-age fetuses were excluded. Cases were classified as group 1 (those with an umbilical artery pulsatility index >95th centile at any scan during target window) or group 2 (those where the umbilical artery pulsatility index was ≤95th centile at all scans). p-Values and odds ratios were calculated. Logistic regression was used to compute odds ratios adjusted for baseline estimated weight z-score, gestational age at delivery, and labor induction.

RESULTS

After exclusions, there were 202 pregnancies in group 1 and 7950 in group 2. Differences in baseline characteristics between the groups include age (median age was 30 for group 1 and 32 for group 2, p < .001), smoking (group 1 were more likely to smoke, p < .001) and labor induction (more common in group 1, p = .03). Among those delivering ≥34 + 0, group 1 were more likely to be small-for-gestational-age and have an abnormal cerebro-placental ratio at the final scan (OR 6.76, CI 4.23-10.80 and OR 5.07, CI 3.37-7.63 respectively), and to develop features of growth restriction (OR 9.85, CI 6.27-15.49). Group 1 were also more likely to deliver <37 + 0 weeks' gestation (OR 1.71, CI 1.13-2.58) and to have birthweight <10th or <3rd centile (OR 5.26, CI 3.65-7.58 and OR 6.13, CI 3.00-12.54 respectively). These associations remained significant when adjusted for estimated weight at the initial scan.

CONCLUSIONS

These data suggest that raised umbilical artery pulsatility index in an appropriately grown fetus at 28 + 0 to 33 + 6 weeks' gestation is associated with subsequent development of growth restriction markers and an increased risk of moderate and severe small-for-gestational-age at birth. This is independent of the estimated weight of these babies at the index scan.

Do specific maternal sensations experienced in late pregnancy correlate to a breech presenting baby? Evaluation of a simple maternal questionnaire

OBJECTIVES

To investigate the effectiveness of a structured questionnaire completed at 36 weeks gestation in predicting breech presentation.

DESIGN

Questionnaire-based study.

SETTING

Tertiary NHS Foundation Trust.

PARTICIPANTS

Women attending for a universally offered 36-week fetal growth scan.

INTERVENTION

Completion of a previously designed maternal questionnaire detailing sensation of fetal movements during the past week, immediately before a routine growth scan.

RESULTS

Between September 01, 2018 and September 30, 2019, 2341 questionnaires were handed out and 2053 were returned. Analysis was performed in 1938 (94.4%) completed questionnaires. Recorded presentation was breech in 109 (5.6%), transverse/oblique in 15 (0.8%), and cephalic in 1814 (93.6%). Women "thinking their baby was breech" had a high positive likelihood ratio, at 11.8 (95% CI 7.4-19.1), but poor sensitivity (27.3%). "Feeling kicks low down or near the bladder" was sensitive for non-cephalic presentation (76.3%) but with poor specificity (48.9%). The questions "kicks low" ("no") (P = 0.013, aOR 2.18 [1.18-4.04]) and 'thinks cephalic ("no")' (P = 0.001, aOR 0.12 (0.04-0.43) were independent risk factors for a non-cephalic presentation.

CONCLUSIONS

The questions posed in this questionnaire could aid the detection of breech presentation, but do not perform better than published data on palpation. Missing a breech presentation near term through palpation alone is well reported. Combining the concept of palpation to exclude breech presentation and these questions may help focus a clinician and improve both palpation skills and breech detection. As a minimum, a woman who believes her baby is breech should be taken seriously.

Multimodal Deep Learning for Predicting Adverse Birth Outcomes Based on Early Labour Data

Cardiotocography (CTG) is a widely used technique to monitor fetal heart rate (FHR) during labour and assess the health of the baby. However, visual interpretation of CTG signals is subjective and prone to error. Automated methods that mimic clinical guidelines have been developed, but they failed to improve detection of abnormal traces. This study aims to classify CTGs with and without severe compromise at birth using routinely collected CTGs from 51,449 births at term from the first 20 min of FHR recordings. Three 1D-CNN and LSTM based architectures are compared. We also transform the FHR signal into 2D images using time-frequency representation with a spectrogram and scalogram analysis, and subsequently, the 2D images are analysed using a 2D-CNNs. In the proposed multi-modal architecture, the 2D-CNN and the 1D-CNN-LSTM are connected in parallel. The models are evaluated in terms of partial area under the curve (PAUC) between 0-10% false-positive rate; and sensitivity at 95% specificity. The 1D-CNN-LSTM parallel architecture outperformed the other models, achieving a PAUC of 0.20 and sensitivity of 20% at 95% specificity. Our future work will focus on improving the classification performance by employing a larger dataset, analysing longer FHR traces, and incorporating clinical risk factors.

The impact of a universal late third-trimester scan for fetal growth restriction on perinatal outcomes in term singleton births: A prospective cohort study

OBJECTIVE

To investigate perinatal mortality, morbidity and obstetric intervention following the introduction of a universal late third-trimester ultrasound scan for growth restriction.

DESIGN

Prospective cohort study.

SETTING

Oxfordshire (OUH), UK.

POPULATION

Women with a non-anomalous singleton pregnancy undergoing pregnancy care and term delivery at OUH with an estimated due date (EDD) of birth between 1 January 2014 and 30 September 2019.

METHODS

Universal ultrasound for fetal growth restriction between 35⁺⁰ and 36⁺⁶ weeks was introduced in 2016. The outcomes of the next 18 631 eligible term pregnancies were compared, adjusting for covariates and time, with the previous 18 636 who had clinically indicated ultrasounds only. 'Screen-positives' for growth restriction were managed according to a pre-determined protocol which included non-intervention for some small-for-gestational-age babies.

MAIN OUTCOME MEASURES

Extended perinatal mortality, a composite of mortality or encephalopathy Grade II-III, and expedited birth. Other outcomes included composite adverse outcomes used elsewhere, detection of low birthweight and birth from 37⁺⁰ to 38⁺⁶ weeks.

RESULTS

Extended perinatal deaths decreased 27% and severe morbidity decreased 33% but neither change was statistically significant (adjusted odd ratio [aOR] 0.53, 95% confidence interval [C1] 00.18-1.56 and aOR 0.71, 95% CI 0.31-1.63). Expedited births changed from 35.2% to 37.7% (aOR 0.99, 95% CI 0.92-1.06). Birthweight (<10th centile) detection using fetal biometry alone was 31.4% and rose to 40.5% if all abnormal scan parameters were used.

CONCLUSION

Improvements in mortality and severe morbidity subsequent to introducing a universal ultrasound for growth restriction are encouraging but remain unclear. Little change in intervention is possible. The antenatal detection of low birthweight remains poor but improves where markers of growth restriction are used.

Prenatal diagnosis of PERCHING syndrome caused by homozygous loss of function variant in the KLHL7 gene

AIMS

A couple were referred for prenatal genetic testing at 31 weeks gestation due to the presence of mild polyhydramnios and multiple central nervous system (CNS) abnormalities, including borderline ventriculomegaly, possible delayed sulcation, an enlarged cisterna magna and small area of calcification around the posterior horns. Testing was initiated to identify any underlying genetic cause.

MATERIALS AND METHODS

Rapid trio exome sequencing (ES) was performed on DNA extracted from parental blood samples and amniotic fluid.

RESULTS

A pathogenic homozygous nonsense variant in KLHL7 (NM_001031710.2) associated with PERCHING syndrome (#617055) was identified.

CONCLUSION

Whilst there are detailed descriptions of the many postnatal phenotypes seen in these patients, there are few reports of features identified during pregnancy. This report is the first published prenatal diagnosis of PERCHING syndrome and provides further information on associated fetal phenotypes. This article is protected by copyright. All rights reserved.

Detection of small- and large-for-gestational age using different combinations of prenatal and postnatal charts

OBJECTIVE

To determine the extent to which the detection rate of small-for-gestational age (SGA) and large-for-gestational age (LGA) at birth is influenced by the use of different combinations of estimated-fetal-weight (EFW) and birth-weight (BW) charts.

METHODS

This was a cohort study of all pregnant women with a singleton term birth receiving care in a university hospital during a 3-year period. All participants underwent a universal 36-week ultrasound scan for EFW measurement and had BW recorded at delivery. Five different reference charts were used for EFW and BW centile calculation. Two-by-two contingency tables were constructed using EFW as the screening test variable and BW as the outcome variable in order to calculate sensitivity, specificity, positive predictive value (PPV) and negative predictive value for all possible chart combinations.

RESULTS

The cohort included 17 678 pregnancies. The sensitivity of EFW < 10^th centile for the detection of BW < 10^th centile ranged from 10.8% to 66.8% and the sensitivity of EFW < 3^rd centile for the detection of BW < 3^rd centile ranged from 4.1% to 66.8%, depending on the charts used. The sensitivity of EFW > 90^th centile for BW > 90^th centile ranged between 22.9% and 68.3%. When locally derived charts for EFW and BW were used, the sensitivity of detection of BW < 10^th centile using EFW < 10^th centile was 43.7% (PPV, 45.5%); for the detection of BW < 3^rd centile using EFW < 3^rd centile, the sensitivity was 25.6% (PPV, 26.7%) and, for the detection of BW > 90^th centile using EFW > 90^th centile, it was 49.6% (PPV, 49.0%).

CONCLUSIONS

Different combinations of EFW and BW charts can yield vastly different detection rates (sensitivity) in the same population cohort and time period. If SGA and LGA detection rates are to be used as a meaningful performance indicator, healthcare systems should follow a clear and predefined methodology that includes explicit definitions of common reference standards. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Ultrasound predictors of adverse outcome in pregnancy complicated by pre-existing and gestational diabetes

INTRODUCTION

Ultrasound assessment of fetuses subjected to hyperglycemia is recommended but, apart from increased size, little is known about its interpretation, and the identification of which large fetuses of diabetic pregnancy are at risk is unclear. Newer markers of adverse outcomes, abdominal circumference growth velocity and cerebro-placental ratio, help to predict risk in non-diabetic pregnancy. Our study aims to assess their role in pregnancies complicated by diabetes.

MATERIAL AND METHODS

This is a retrospective analysis of a cohort of singleton, non-anomalous fetuses of women with pre-existing or gestational diabetes mellitus, and estimated fetal weight at the 10th centile or above. Gestational diabetes was diagnosed by selective screening of at risk groups. A universal ultrasound scan was offered at 20 and 36 weeks of gestation. Estimated fetal weight, abdominal circumference growth velocity, presence of polyhydramnios, and cerebro-placental ratio were evaluated at the 36-week scan. A composite adverse outcome was defined as the presence of one or more of perinatal death, arterial cord pH less than 7.1, admission to Neonatal Unit, 5-minute Apgar less than 7, severe hypoglycemia, or cesarean section for fetal compromise. A chi-squared test was used to test the association of estimated fetal weight at the 90th centile or above, polyhydramnios, abdominal circumference growth velocity at the 90th centile or above, and cerebro-placental ratio at the 5th centile or below with the composite outcome. Logistic regression was used to assess which ultrasound markers were independent risk factors. Odds ratios of composite adverse outcome with combinations of independent ultrasound markers were calculated.

RESULTS

A total of 1044 pregnancies were included, comprising 87 women with pre-existing diabetes mellitus and 957 with gestational diabetes. Estimated fetal weight at the 90th centile or above, abdominal circumference growth velocity at the 90th centile or above, cerebro-placental ratio at the 5th centile or below, but not polyhydramnios, were significantly associated with adverse outcomes: odds ratios (95% confidence intervals) 1.85 (1.21-2.84), 1.54 (1.02-2.31), 1.92 (1.21-3.30), and 1.53 (0.79-2.99), respectively. Only estimated fetal weight at the 90th centile or above and cerebro-placental ratio at the 5th centile or below were independent risk factors. The greatest risk (odds ratio 6.85, 95% confidence interval 2.06-22.78) was found where both the estimated fetal weight is at the 90th centile or above and the cerebro-placental ratio is at the 5th centile or below.

CONCLUSIONS

In diabetic pregnancies, a low cerebro-placental ratio, particularly in a macrosomic fetus, confers additional risk.

Function and Safety of SlowflowHD Ultrasound Doppler in Obstetrics

SlowflowHD is a new ultrasound Doppler imaging technology that allows visualization of flow within small blood vessels. In this mode, a proprietary algorithm differentiates between low-speed flow and signals attributed to tissue motion so that microvessel vasculature can be examined. Our objectives were to describe the low-velocity Doppler mode principles, to assess the bone thermal index (TIb) safety parameter in obstetric ultrasound scans and to evaluate adherence to professional guidelines. To achieve the latter goals, we retrospectively reviewed prospectively collected ultrasound images and video clips from pregnancy ultrasound scans at >10 wk of gestation over 4 mo. We used a custom-built optical character recognition-based software to automatically identify all images and video clips using this technology and extract the TIb. Overall, a total of 185 ultrasound scans performed by three fetal medicine physicians were included, of which 60, 54 and 71 scans were first-, second- and third-trimester scans, respectively. The mean (highest recorded) TIb values were 0.32 (0.70), 0.23 (0.70) and 0.32 (0.60) in the first, second, and third trimesters, respectively. Thermal index values were within recommended values set by the World Federation for Ultrasound in Medicine and Biology American Institute of Ultrasound in Medicine and British Medical Ultrasound Society in all scans.

Late pregnancy ultrasound parameters identifying fetuses at risk of adverse perinatal outcomes: a protocol for a systematic review of systematic reviews

INTRODUCTION

Stillbirths and neonatal deaths are leading contributors to the global burden of disease and pregnancy ultrasound has the potential to help decrease this burden. In the absence of high-Grading of Recommendations Assessment, Development and Evaluation (GRADE) evidence on universal obstetric ultrasound screening at or close to term, many different screening strategies have been proposed. Systematic reviews have rapidly increased over the past decade owing to the diverse nature of ultrasound parameters and the wide range of possible adverse perinatal outcomes. This systematic review will summarise the evidence on key ultrasound parameters in the published literature to help develop an obstetric ultrasound protocol that identifies pregnancies at risk of adverse perinatal outcomes at or close to term.

METHODS

This study will follow the recent Cochrane guidelines for a systematic review of systematic reviews. A comprehensive literature search will be conducted using Embase (OvidSP), Medline (OvidSP), CDSR, CINAHL (EBSCOhost) and Scopus. Systematic reviews evaluating at least one ultrasound parameter in late pregnancy to detect pregnancies at risk of adverse perinatal outcomes will be included. Two independent reviewers will screen, assess the quality including the risk of bias using the ROBIS tool, and extract data from eligible systematic reviews that meet the study inclusion criteria. Overlapping data will be assessed and managed with decision rules, and study evidence including the GRADE assessment of the certainty of results will be presented as a narrative synthesis as described in the Cochrane guidelines for an overview of reviews.

ETHICS AND DISSEMINATION

This research uses publicly available published data; thus, an ethics committee review is not required. The findings will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021266108.

Improving diagnostic accuracy in pregnancy with individualised, gestational age-specific reference intervals

BACKGROUND AND AIMS

Investigations in pregnancy should be interpreted using pregnancy-specific reference intervals (RIs). However, because of the progressive nature of pregnancy, even pregnancy-specific RIs may not be equally representative at different gestations. We proposed that gestational age-specific RIs may increase diagnostic accuracy over those with fixed limits.

MATERIALS AND METHODS

The trajectory of platelets was mapped in 32,778 pregnant women, using 116,798 results. Then we evaluated the accuracy with which a low measurement in early pregnancy (<3^rd centile) predicted thrombocytopaenia at term, compared to the existing limit (<150 x10⁹/L).

RESULTS

Platelets fell by 14.8% between 8-40 weeks. Platelets below the 3^rd centile before 20 weeks predicted thrombocytopaenia at term (<100 x10⁹/L) with a significantly greater degree of accuracy than a fixed limit (AUC 0.86 vs. 0.76, p=0.004).

CONCLUSION

Pregnancy-specific RIs can be defined using routinely collected hospital data, and the abundance of such freely available data enables a detailed investigation of temporal changes throughout gestation. Individualised RIs offer improved accuracy profiles, over and above those already derived specifically from pregnant populations. Clinicians should consider how this may be used to improve diagnostic accuracy for biomarkers used in current clinical practice, and those yet to be defined.

White blood cells in pregnancy: reference intervals for before and after delivery

BACKGROUND

White blood cells (WBC) are commonly measured to investigate suspected infection and inflammation in pregnant women, but the pregnancy-specific reference interval is variably reported, increasing diagnostic uncertainty in this high-risk population. It is essential that clinicians can interpret WBC results in the context of normal pregnant physiology, given the huge global burden of infection on maternal mortality.

METHODS

We performed a longitudinal, repeated measures population study of 24,318 pregnant women in Oxford, UK, to map the trajectory of WBC between 8-40 weeks of gestation. We defined 95% reference intervals (RI) for total WBC, neutrophils, lymphocytes, eosinophils, basophils, and monocytes for the antenatal and postnatal periods.

FINDINGS

WBC were measured 80,637 times over five years. The upper reference limit for total WBC was elevated by 36% in pregnancy (RI 5.7-15.0×109/L), driven by a 55% increase in neutrophils (3.7-11.6×109/L) and 38% increase in monocytes (0.3-1.1×109/L), which remained stable between 8-40 weeks. Lymphocytes were reduced by 36% (1.0-2.9×109/L), while eosinophils and basophils were unchanged. Total WBC was elevated significantly further from the first day after birth (similar regardless of the mode of delivery), which resolved to pre-delivery levels by an average of seven days, and to pre-pregnancy levels by day 21.

INTERPRETATION

There are marked changes in WBC in pregnancy, with substantial differences between cell subtypes. WBC are measured frequently in pregnant women in obstetric and non-obstetric settings, and results should be interpreted using a pregnancy-specific RI until delivery, and between days 7-21 after childbirth.

FUNDING

None.

The impact of individual sonographer variation on the detection of small for gestational age fetuses using a third trimester growth scan

OBJECTIVES

Detection of small for gestational age (SGA) fetuses in a third trimester ultrasound could be affected by variation in sonographer performance.

METHODS

Retrospective analysis of all singleton, non-anomalous ultrasound examinations between 35⁺⁰ -36⁺⁶ weeks gestation, in a single institution where a universal 36-week scan is offered. Screen positive was defined as estimated fetal weight (EFW) <10th centile; SGA was birthweight <10th centile. Individual sonographers' distributions of head circumference (HC), abdominal circumference (AC) and femur length (FL) were used to assess sonographers' screen positive rate (SPR), detection rate (DR) and true positive rate (TPR). Univariate and multivariate regression analysis was performed to assess the association between the sonographers' mean and SD (SD) for HC, AC, FL and their SPR, DR and TPR.

RESULTS

There were 27 sonographers performing more than 50 examinations per year, a total of 5691 scans. The mean incidence of SGA was 10.0%. For an overall SPR of 9.4%, the overall DR was 43.8% (95% CI: 39.6% - 48.1%) and the overall TPR was 46.5% (95% CI: 42.9% - 50.2%). Higher AC scatter (SD difference up to 11.6 mm) was associated with higher SPR (P = 0.001). Lower mean FL (difference up to 3.6 mm) was associated with higher SPR (P = 0.003) and higher DR (P = 0.002). As a result, DR varied amongst different sonographers between 14.3% and 85.7% and TPR varied between 8.3% and 100.0%.

CONCLUSIONS

Monitoring of individual AC and FL distributions is a simple and effective tool for institutional quality assurance.

Pregnancy-specific reference intervals for C-reactive protein improve diagnostic accuracy for infection: A longitudinal study

BACKGROUND AND AIMS

Infections are a major cause of maternal mortality. C-reactive protein (CRP), a commonly-used inflammatory marker, is widely used to inform diagnosis, but the upper limit of normal in pregnancy is uncertain. We have defined trimester-specific reference intervals for CRP and evaluated their diagnostic accuracy for infection.

MATERIALS AND METHODS

Development cohort: longitudinal study of pregnant women to determine 95% reference intervals. Evaluation cohort: diagnostic accuracy study to evaluate these intervals in 50 women with suspected intrauterine infection.

RESULTS

In these 322 healthy pregnant women, CRP was substantially higher than in most non-pregnant populations. CRP was similar in each trimester, with an upper reference limit of 19 mg/L. CRP increased linearly with body mass index (p < 0.0001). The sensitivity and specificity of CRP for diagnosing chorioamnionitis were 73% and 86%, respectively. The overall diagnostic accuracy using the pregnancy-specific reference interval was significantly better than that of the existing standard (p = 0.03).

CONCLUSIONS

CRP is a widely-used clinical tool in pregnancy, and a pregnancy-specific reference interval should be used to optimise diagnostic accuracy. Chorioamnionitis was used as an example of a localised infection with well-defined outcomes, but pregnancy-specific RIs for CRP should be considered in any clinical setting including pregnant women.

The impact of a routine late third trimester growth scan on the incidence, diagnosis, and management of breech presentation in Oxfordshire, UK: A cohort study

BACKGROUND

Breech presentation at term contributes significantly to cesarean section (CS) rates worldwide. External cephalic version (ECV) is a safe procedure that reduces term breech presentation and associated CS. A principal barrier to ECV is failure to diagnose breech presentation. Failure to diagnose breech presentation also leads to emergency CS or unplanned vaginal breech birth. Recent evidence suggests that undiagnosed breech might be eliminated using a third trimester scan. Our aim was to evaluate the impact of introducing a routine 36-week scan on the incidence of breech presentation and of undiagnosed breech presentation.

METHODS AND FINDINGS

We carried out a population-based cohort study of pregnant women in a single unit covering Oxfordshire, United Kingdom. All women delivering between 37+0 and 42+6 weeks gestational age, with a singleton, nonanomalous fetus over a 4-year period (01 October 2014 to 30 September 2018) were included. The mean maternal age was 31 years, mean BMI 26, 44% were nulliparous, and 21% were of non-white ethnicity. Comparisons between the 2 years before and after introduction of routine 36-week scan were made for 2 primary outcomes of (1) the incidence of breech presentation and (2) undiagnosed breech presentation. Secondary outcomes related to ECV, mode of birth, and perinatal outcomes. Relative risks (RRs) with 95% confidence intervals (CIs) are reported. A total of 27,825 pregnancies were analysed (14,444 before and 13,381 after). A scan after 35+0 weeks was performed in 5,578 (38.6%) before, and 13,251 (99.0%) after (p < 0.001). The incidence of breech presentation at birth did not change significantly (2.6% and 2.7%) (RR 1.02; 95% CI 0.89, 1.18; p = 0.76). The rate of undiagnosed breech before labour reduced, from 22.3% to 4.7% (RR 0.21; 95% CI 0.12, 0.36; p < 0.001). Vaginal breech birth rates fell from 10.3% to 5.3% (RR 0.51; 95% CI 0.30, 0.87; p = 0.01); nonsignificant increases in elective CS rates and decreases in emergency CS rates for breech babies were seen. Neonatal outcomes were not significantly altered. Study limitations include insufficient numbers to detect serious adverse outcomes, that we cannot exclude secular changes over time which may have influenced our results, and that these findings are most applicable where a comprehensive ECV service exists.

CONCLUSIONS

In this study, a universal 36-week scan policy was associated with a reduction in the incidence but not elimination of undiagnosed term breech presentation. There was no reduction in the incidence of breech presentation at birth, despite a comprehensive ECV service.

How often do we incidentally find a fetal abnormality at the routine third-trimester growth scan? A population-based study

BACKGROUND

Third-trimester scans are increasingly used to try to prevent adverse outcomes associated with abnormalities of fetal growth. Unexpected fetal malformations detected at third-trimester growth scans are rarely reported.

OBJECTIVE

To determine the incidence and type of fetal malformations detected in women attending a routine third-trimester growth scan.

STUDY DESIGN

This was a population-based study of all women with singleton pregnancy attending antenatal care over a 2-year period in Oxfordshire, UK. Women who had a viable singleton pregnancy at dating scan were included. Women had standard obstetrical care including the offer of a routine dating scan and combined screening for trisomies; a routine anomaly scan at 18 to 22 weeks; and a routine third-trimester growth scan at 36 weeks. The third-trimester scan comprises assessment of fetal presentation, amniotic fluid, biometry, umbilical and middle cerebral artery Dopplers, but no formal anatomic assessment is undertaken. Scans are performed by certified sonographers or clinical fellows (n=54), and any suspected abnormalities are evaluated by a team of fetal medicine specialists. We assessed the frequency and type of incidental congenital malformations identified for the first time at this third-trimester scan. All babies were followed-up after birth for a minimum of 6 months.

RESULTS

There were 15,244 women attending routine antenatal care. Anomalies were detected in 474 (3.1%) fetuses as follows: 103 (21.7%) were detected before the anomaly scan, 174 (36.7%) at the anomaly scan, 11 (2.3%) after the anomaly scan and before the third-trimester scan, 43 (9.1%) at the third-trimester scan and 143 (30.2%) after birth. The 43 abnormalities were found in a total of 13,023 women who had a 36 weeks scan, suggesting that in 1 out of 303 (95% confidence interval, 233-432) women attending such a scan, a new malformation was detected. Anomalies detected at the routine third-trimester scan were of the urinary tract (n=30), central nervous system (5), simple ovarian cysts (4), chromosomal (1), splenic cyst (1), skeletal dysplasia (1), and cutaneous lymphangioma (1). Most urinary tract anomalies were renal pelvic dilatation, which showed spontaneous resolution in 57% of the cases.

CONCLUSION

When undertaking a program of routine third-trimester growth scans in women who have had previous screening scans, an unexpected congenital malformation is detected in approximately 1 in 300 women.

How often do we identify fetal abnormalities during routine third-trimester ultrasound? A systematic review and meta-analysis

BACKGROUND

Routine third-trimester ultrasound is frequently offered to pregnant women to identify fetuses with abnormal growth. Infrequently, a congenital anomaly is incidentally detected.

OBJECTIVE

To establish the prevalence and type of fetal anomalies detected during routine third-trimester scans using a systematic review and meta-analysis.

SEARCH STRATEGY

Electronic databases (MEDLINE, Embase and the Cochrane library) from inception until August 2019.

SELECTION CRITERIA

Population-based studies (randomised control trials, prospective and retrospective cohorts) reporting abnormalities detected at the routine third-trimester ultrasound performed in unselected populations with prior screening. Case reports, case series, case-control studies and reviews without original data were excluded.

DATA COLLECTION AND ANALYSIS

Prevalence and type of anomalies detected in the third trimester. We calculated pooled prevalence as the number of anomalies per 1000 scans with 95% confidence intervals. Publication bias was assessed.

MAIN RESULTS

The literature search identified 9594 citations: 13 studies were eligible representing 141 717 women; 643 were diagnosed with an unexpected abnormality. The pooled prevalence of a new abnormality diagnosed was 3.68 per 1000 women scanned (95% CI 2.72-4.78). The largest groups of abnormalities were urogenital (55%), central nervous system abnormalities (18%) and cardiac abnormalities (14%).

CONCLUSION

Combining data from 13 studies and over 140 000 women, we show that during routine third-trimester ultrasound, an incidental fetal anomaly will be found in about 1 in 300 scanned women. This information should be taken into account when taking consent from women for third-trimester ultrasound and when designing and assessing cost of third-trimester ultrasound screening programmes.

TWEETABLE ABSTRACT

One in 300 women attending a third-trimester scan will have a finding of a fetal abnormality.

Extreme preterm birth in the right place: a quality improvement project

Extreme preterm birth is a major precursor to mortality and disability. Survival is improved in babies born in specialist centres but for multiple reasons this frequently does not occur. In the Thames Valley region of the UK in 2012-2014, covering 27 000 births per annum, about 50% of extremely premature babies were born in a specialist centre. Audit showed a number of potential areas for improvement. We used regional place of birth data and compared the place of birth of extremely premature babies for 2 years before our intervention and for 4 years (2014-2018) after we started. We aimed to improve the proportion of neonates born in a specialist centre with three interventions: increasing awareness and education across the region, by improving and simplifying the referral pathway to the local specialised centre, and by developing region-wide guidelines on the principal precursors to preterm birth: preterm labour and expedited delivery for fetal growth restriction. There were 147 eligible neonates born within the network in the 2 years before the intervention and 80 (54.4%) were inborn in a specialised centre. In the 4 years of and following the intervention, there were 334 neonates of whom 255 were inborn (76.3%) (relative risk of non-transfer 0.50 (95% CI 0.39 to 0.65), p<0.001). Rates showed a sustained improvement. The proportion of extremely premature babies born in specialist centres can be significantly improved by a region-wide quality improvement programme. The interventions and lessons could be used for other areas and specialties.

Intrapartum hypoxia and sexual dimorphism in adverse perinatal outcomes

OBJECTIVES

The aim of this study is to evaluate whether markers of intrapartum hypoxia differ according to sex, and if this could explain the increased risk of adverse perinatal outcomes in males.

STUDY DESIGN

This is a retrospective observational cohort study of non-anomalous, singleton deliveries >36 completed weeks' gestation at a UK teaching hospital over a 4.5 year period. Absent or incomplete cord gas results were excluded and the remaining data were validated according to an established method. The relations between sex and both arterial pH and a composite variable, 'fetal distress' (cases in which operative delivery or caesarean section were undertaken for presumed fetal compromise), were examined using independent samples t-test and Chi-square test. Odds ratios with 95 % confidence intervals were calculated to describe the relation between fetal sex and intermediate-term adverse outcomes. Binary logistic regression was performed to generate odds ratios (with 95 % confidence intervals) adjusted for arterial pH and fetal distress. This was repeated to adjust for labor and induction of labor.

RESULTS

There were eligible 8758 cases, of which 4655 were male and 4103 female, from a total of 39,148 deliveries during the study period. Neonatal unit admission (OR 1.54, 95 % CI; 1.31-1.80), renal impairment (OR 1.63, 95 % CI; 1.15-2.32), neurological impairment (OR 1.73, 95 % CI; 1.06-2.84) and a composite adverse outcome (OR 1.73, 95 % CI; 1.29-2.33) were all more likely in males, even after adjusting for labor and induction of labor, both of which were more likely males. The mean cord arterial pH of males was lower (7.23 vs 7.24, P = 0.019) although they were not more likely to be acidemic with a pH <7.0 (males 43 (0.92 %) vs females 41 (1.00 %), P = 0.717), and males were also more likely to have fetal distress (834 (17.9 %) vs 588 (14.3 %), P = <0.001). Being male remained associated with adverse outcomes despite adjustment for arterial pH and fetal distress.

CONCLUSION

Despite a lower mean cord arterial pH and greater incidence of fetal distress in males, intrapartum hypoxia does not account for their worse neonatal outcomes.

Randomized Interventional Study on Prediction of Preeclampsia/Eclampsia in Women With Suspected Preeclampsia: INSPIRE

Supplemental Digital Content is available in the text.

The ratio of maternal serum sFlt-1 (soluble fms-like tyrosine kinase 1) to PlGF (placental growth factor) has been used retrospectively to rule out the occurrence of preeclampsia, a pregnancy hypertensive disorder, within 7 days in women presenting with clinical suspicion of preeclampsia. A prospective, interventional, parallel-group, randomized clinical trial evaluated the use of sFlt-1/PlGF ratio in women presenting with suspected preeclampsia. Women were assigned to reveal (sFlt-1/PlGF result known to clinicians) or nonreveal (result unknown) arms. A ratio cutoff of 38 was used to define low (≤38) and elevated risk (>38) of developing the condition in the subsequent week. The primary end point was hospitalization within 24 hours of the test. Secondary end points were development of preeclampsia and other adverse maternal-fetal outcomes. We recruited 370 women (186 reveal versus 184 nonreveal). Preeclampsia occurred in 85 women (23%). The number of admissions was not significantly different between groups (n=48 nonreveal versus n=60 reveal; P=0.192). The reveal trial arm admitted 100% of the cases that developed preeclampsia within 7 days, whereas the nonreveal admitted 83% (P=0.038). Use of the test yielded a sensitivity of 100% (95% CI, 85.8–100) and a negative predictive value of 100% (95% CI, 97.1–100) compared with a sensitivity of 83.3 (95% CI, 58.6–96.4) and negative predictive value of 97.8 (95% CI, 93.7–99.5) with clinical practice alone. Use of the sFlt-1/PlGF ratio significantly improved clinical precision without changing the admission rate.

The outcomes of pregnancies with reduced fetal movements: A retrospective cohort study

INTRODUCTION

The objective of this study was to examine the outcomes and interventions in pregnant women presenting with a perception of reduced fetal movements (RFM), and to determine if repeated episodes of RFM increase the risk of adverse outcomes.

MATERIAL AND METHODS

This was a retrospective cohort study conducted in six NHS hospitals within the Thames Valley network region, UK and one neighboring hospital, an area with approximately 31 000 births annually. All women with a primary presentation of perceived RFM after 24 completed weeks of gestation during the month of October 2016 were included in the study. Prospective records in all units were examined and individual case-notes were reviewed. Pregnancy and neonatal outcomes and their relation with recurrent presentations with RFM were examined using relative risks with 95% CI. The main outcome measures are described. Neonatal outcomes measured were perinatal mortality, neonatal unit admission, abnormal cardiotocography at presentation, a composite severe morbidity outcome of Apgar <7 at 5 minutes or arterial pH <7.0 or encephalopathy, and birthweight. Pregnancy outcomes measured were induction of labor, cesarean section, admission and ultrasound usage rates.

RESULTS

In all, 591 women presented with RFM during the month; using annual hospital birth figures, the incidence of RFM was estimated at 22.6% (range 14.9%-32.5%). More than 1 presentation of RFM occurred in 273 (46.2%). All 3 deaths (0.5%) were at the first presentation. More than 1 presentation was associated with higher induction rates (56.0% vs 31.9%), but no increase in any adverse outcomes including small-for-gestational-age.

CONCLUSIONS

Reduced fetal movements, and recurrent episodes, are common, and lead to considerable resource usage and obstetric intervention. We found no evidence to suggest that recurrent episodes increase pregnancy risk.

External cephalic version at term: a cohort study of 18 years' experience

OBJECTIVE

To analyse the outcome of referrals for external cephalic version (ECV).

DESIGN

Retrospective cohort study of prospectively collected data.

SETTING

Major university hospital, UK.

SAMPLE

Women with non-cephalic presentation at term and no prior caesarean, referred to a specialist clinic.

METHODS

Details of referrals, ECV attempts, and perinatal outcomes were prospectively collected and analysed. Multivariate binary logistic regression models were created to determine independent predictors of ECV success, reversion, and spontaneous version.

MAIN OUTCOME MEASURES

External cephalic version success rates, predictors of success and cephalic presentation at birth, and perinatal outcomes.

RESULTS

Three thousand eight had confirmed breech presentation; 2614 women underwent ECV. Ineligibility for ECV occurred in 117 breech presentations (3.9%), and 297 eligible women (10.2%) declined it. ECV was successful in 1280 (49.0%, 95% CI 47.0-50.9%) (40% in nulliparous women; 64% in others); 1234 (97.3%) were cephalic at birth. Spontaneous version after failure occurred in 4.3% and was more common in multiparas (aOR 2.47, 95% CI 1.43-4.26) and those with a posterior fetal back (aOR 6.09, 95% CI 1.90-19.53). Reversion after successful ECV occurred in 2.2%. In women with a successful ECV whose fetus remained cephalic at birth, 85.7% delivered vaginally. The corrected perinatal mortality of the ECV cohort was 0.12%.

CONCLUSION

External cephalic version has a low complication rate and is effective for most breech presentations, enabling vaginal birth and avoiding caesarean section.

TWEETABLE ABSTRACT

External cephalic version can safely be performed with most breech presentations.

Using fetal abdominal circumference growth velocity in the prediction of adverse outcome in near-term small-for-gestational-age fetuses

OBJECTIVE

To investigate whether abdominal circumference growth velocity (ACGV) improves the prediction of perinatal outcome in small-for-gestational-age (SGA) fetuses beyond that afforded by estimated fetal weight (EFW) and cerebroplacental ratio (CPR).

METHODS

A cohort of 235 singleton SGA fetuses at 36-38 weeks' gestation was examined. ACGV, EFW and CPR centiles were calculated. ACGV centile was determined using data from a large database of 19-21- and 36-38-week scans in an unselected population. Binary variables of ACGV < 10^th , EFW < 3^rd and CPR < 5^th centiles were defined as abnormal. Two composite adverse outcomes (CAO) were explored: CAO-1 defined as at least one of umbilical artery pH < 7.10, 5-min Apgar score < 7 or neonatal unit admission, and CAO-2 that included in addition hypoglycemia, intrapartum fetal distress and perinatal death. Univariate and multivariate logistic regression analyses were performed to analyze the relationship between the three risk factors and their predictive value for CAO. The change in screening performance afforded by adding ACGV to EFW and CPR was assessed and receiver-operating characteristics (ROC) curves were calculated.

RESULTS

ACGV < 10^th centile was an independent risk factor for CAO. The sensitivity, specificity, positive and negative likelihood ratios of a predictive model based on EFW < 3^rd centile and CPR < 5^th centile were, respectively, 51%, 70%, 1.71 and 0.69 for CAO-1 and 41%, 70%, 1.39 and 0.83 for CAO-2. After addition of ACGV < 10^th centile to the model, the respective values were 82%, 46%, 1.54 and 0.38 for CAO-1 and 71%, 47%, 1.34 and 0.62 for CAO-2. Using continuous variables, the areas under the ROC curves improved marginally from 0.669 (95% CI, 0.604-0.729) to 0.741 (95% CI, 0.677-0.798) for CAO-1 and from 0.646 (95% CI, 0.580-0.707) to 0.700 (95% CI, 0.633-0.759) for CAO-2 after addition of ACGV to the model.

CONCLUSIONS

ACGV is a risk factor for adverse neonatal outcome that is independent of EFW and of CPR, although any improvement in the prediction of adverse outcome is not statistically significant. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

An objective scoring method to evaluate image quality of middle cerebral artery Doppler

Objective: To validate an objective scoring system for middle cerebral artery (MCA) pulsed wave Doppler images.Method: From an image database of routine 36-week scans, a random sample of MCA Doppler images was selected. Two reviewers rated the images subjectively as acceptable or unacceptable. Subsequently they used an objective 6-point image scoring system and awarded one point for each of the following: (1) anatomical site, (2) magnification, (3) angle of insonation, (4) image clarity, (5) sweep speed adjustment, and (6) velocity scale and baseline adjustment. Image scores 4-6 were defined as good quality whereas 0-3 as poor. The subjective and objective agreement between the two reviewers was compared using the adjusted Kappa statistic.Results: A total of 124 images were assessed. Using objective scoring the agreement rate between reviewers increased to 91.9% (κ = 0.839) compared to subjective agreement 75.8% (κ = 0.516). The agreement for each criterion was: anatomical site 91.1% (κ = 0.823), magnification 95.2% (κ = 0.903), clarity 83.9% (κ = 0.677), angle 96.0% (κ = 0.919), sweep speed 98.4% (κ = 0.968), and velocity scale and baseline 94.4% (κ = 0.887).Conclusion: Objective assessment of MCA Doppler images using a 6-point scoring system has greater interobserver agreement than subjective assessment and could be used for MCA Doppler quality assurance.

Small-for-gestational-age babies after 37 weeks: impact study of risk-stratification protocol

OBJECTIVE

Although no clear evidence exists, many international guidelines advocate early-term delivery of small-for-gestational-age (SGA) fetuses. The aim of this study was to determine whether a risk-stratification protocol in which low-risk SGA fetuses are managed expectantly beyond 37 weeks affects perinatal and maternal outcomes.

METHODS

This was an impact study examining data collected over a 39-month period (1 January 2013 to 30 April 2016) at a tertiary referral unit. The study included women who were referred to the fetal medicine unit with a singleton non-anomalous fetus diagnosed antenatally as SGA (estimated fetal weight < 10^th centile) from 36 + 0 weeks' gestation. In 2014, a protocol for management of SGA was introduced, which included risk stratification with surveillance and expectant management after 37 weeks for lower-risk babies (protocol group). This was compared with the previous strategy, which recommended delivery at around 37 weeks (pre-protocol group). Primary outcome was neonatal composite adverse outcome.

RESULTS

In the pre-protocol group, there were 138 SGA babies; in the protocol group there were 143. Mean gestational ages at delivery were 37.4 weeks in the pre-protocol group and 38.2 weeks in the protocol group (P = 0.04). The incidence of neonatal composite adverse outcome was lower in the protocol group (9% vs 22%; P < 0.01), as was neonatal unit admission (13% vs 39%; P < 0.01). Induction of labor and Cesarean section rates were lower, and vaginal delivery rate (83% vs 60%; P < 0.01) was higher, in the protocol group. Most of the differences were as a result of delayed delivery of SGA babies that were stratified as low risk.

CONCLUSIONS

The findings of this study suggest that protocol-based management of SGA babies may improve outcome, and that identification of moderate SGA should not in isolation prompt delivery. Larger numbers are required to assess any impact on perinatal mortality. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Umbilical cord arterial base deficit and arterial pH as predictors of adverse outcomes among term neonates

OBJECTIVE

To determine the importance of arterial pH and arterial base deficit (ABD) for predicting adverse outcomes among all term neonates, regardless of acidemic status.

METHODS

The present observational cohort study included consecutive term, non-anomalous singleton neonates with validated paired cord gas data at a single UK teaching hospital between June 23, 2005, and December 31, 2009. Outcomes included encephalopathy (Sarnat grade 2-3) and/or death; 5-minute Apgar score below 7; a composite neurologic adverse outcome; and systemic involvement. Comparison of areas under the curve and hierarchical logistical regressions were used to examine the importance of arterial pH and arterial base deficit (ABD) in predicting adverse outcomes.

RESULTS

There were 8759 neonates included. In all, 111 (1.3%) neonates had high ABD (≥12 mmol/L). Encephalopathy and/or death was recorded in 17 (0.2%) neonates in the whole cohort and 6 (5.4%) from the high ABD group. The mean arterial pH values for these two groups were 7.23 and 7.03, respectively. Comparison of the area under the receiver operating characteristic curves showed that adding ABD to arterial pH did not improve the prediction. Further, hierarchical logistic regression analysis demonstrated that ABD was not an independent predictor of adverse outcomes when adjusted for arterial pH.

CONCLUSIONS

ABD demonstrated no predictive value for adverse neonatal outcomes beyond using arterial pH alone.

Arteriovenous differences in cord blood gas analysis and the prediction of adverse neonatal outcome

INTRODUCTION

The aim of this paper was to determine whether arteriovenous differences of pH and pCO₂ are useful predictors of adverse neonatal outcome in acidemic neonates.

MATERIAL AND METHODS

An established database of 8759 term, singleton, non-anomalous neonates with validated cord gases and outcomes [Encephalopathy (Grade 2/3), Apgar <7 at five minutes and composite neonatal outcomes of neurological and systemic involvement] was used. Analysis was of the cohort of the 520 acidemic (arterial pH <7.10) neonates. Chi-square tests with odds ratio (OR), 95% CI were calculated for dichotomous cut-offs of differences; hierarchical logistic regression was used to examine the predictive performance over and above arterial pH.

RESULTS

Arteriovenous hydrogen ion concentration ([H⁺ ion]) differences do not predict neonatal outcomes except low Apgar scores, and large pCO₂ differences are associated with worse neonatal outcomes. Nevertheless, neonates with large arteriovenous [H⁺ ion] and pCO₂ differences have lower arterial pH values. Hierarchical regression demonstrates that arteriovenous pCO₂ differences do not add predictive value beyond arterial pH and arteriovenous [H⁺ ion] adds only to the prediction of low Apgar scores.

CONCLUSIONS

Arteriovenous differences of [H⁺ ion] and pCO₂ are not useful independent predictors of adverse neonatal outcomes in acidemic neonates.

Automated Visualization and Quantification of Spiral Artery Blood Flow Entering the First-Trimester Placenta, Using 3-D Power Doppler Ultrasound

The goal of our research was to quantify the placental vascularity in 3-D at 11-13 + 6 wk of pregnancy at precise distances from the utero-placental interface (UPI) using 3-D power Doppler ultrasound. With this automated image analysis technique, differences in vascularity between normal and pathologic pregnancies may be observed. The algorithm was validated using a computer-generated image phantom and applied retrospectively in 143 patients. The following features from the PD data were recorded: The number of spiral artery jets into the inter-villous space, total geometric and PD area. These were automatically measured at discrete millimeter distances from the UPI. Differences in features were compared with pregnancy outcomes: Pre-eclamptic versus normal, all small-for-gestational age (SGA) to appropriate-for-gestational age (AGA) patients and AGA versus SGA in normotensives (Mann-Whitney). The Benjamini-Hochberg procedure was used (false discovery rate 10%) for multiple comparison testing. Features decreased with increasing distance from the UPI (Kruskal-Wallis test; p <0.001). At 2- 3 mm from the UPI, all features were smaller in pre-eclamptic compared with normal patients and for some in SGA compared with AGA patients (p <0.05). For AGA versus SGA in normotensive patients, no significant differences were found. Number of jets measured at 2-5 mm from the UPI did not vary because of the position of the placenta in the uterus (ANOVA; p > 0.05). This method provides a new in-vivo imaging tool for examining spiral artery development through pregnancy. Size and number of entrances of blood flow into the UPI could potentially be used to identify high-risk pregnancies and may provide a new imaging biomarker for placental insufficiency.

The influence of fetal sex on the antenatal diagnosis of small for gestational age

OBJECTIVE

We evaluated the influence of fetal sex on the antenatal diagnosis and detection of small for gestational age (SGA).

METHODS

The cohort consisted of unselected singleton pregnancies, undergoing routine biometry and cerebroplacental ratio (CPR) assessment at 36 weeks. Locally fitted equations for centiles and Z scores were used. "Ultrasound SGA" was defined as estimated fetal weight (EFW) < 10th centile, "SGA at birth" as birthweight (BW) < 10th centile adjusted for sex.

RESULTS

Among 4112 pregnancies, there were 235 female "ultrasound SGA" fetuses and 177 male; (odds ratios (OR) 1.502 (1.223 - 1.845)); the detection rate of SGA at birth was 50.6% and 40.9%, respectively (OR 1.479 (0.980 - 2.228)). In "ultrasound SGA" girls the abdominal circumference growth velocity (ACGV) between 20 and 36 weeks was less frequently in the lowest decile (OR 0.490 (0.320 - 0.750)), with no differences in CPR.

CONCLUSIONS

Females are more commonly diagnosed as SGA; those diagnosed may be at less risk than males.

A reference range of fetal abdominal circumference growth velocity between 20 and 36 weeks' gestation

OBJECTIVE

To create a single equation and reference range for abdominal circumference growth velocity (ACGV) between 20 and 36 weeks in singleton pregnancies.

METHOD

Observational study of pregnant women having routine scans for abdominal circumference (AC) at 20 and 36 weeks' gestation. Exclusion criteria were multiple pregnancy, abnormal karyotype, major fetal abnormalities, and absent data on first-trimester dating. Scan image quality and AC measurement reliability were assessed according to INTERGROWTH-21st criteria. Regression models for the AC mean and standard deviation were fitted separately at 20 and 36 weeks, and z scores were calculated. Abdominal circumference growth velocity was defined as the z score difference between 20 and 36 weeks divided by the interval in days and multiplied by 100.

RESULTS

The study population included 3334 fetuses. The equation for ACGV is (((AC₃₆  - 53.090 - 1.081*GA₃₆ )/(0.057638*GA₃₆  + 0.622741)) - ((AC₂₀  + 68.349 - 1.571*GA₂₀ )/(0.06265*GA₂₀  - 2.55361)))*100/(GA₃₆  - GA₂₀ ), where AC is expressed in millimeters and GA is gestational age in days. The 3rd, 5th, 10th, 50th, 90th, 95th, and 97th centiles are -1.8997, -1.6785, -1.3091, -0.0069, 1.3255, 1.7279, 1.9973, respectively.

CONCLUSION

We have defined ACGV between 20 and 36 weeks, and we have established its reference range. Further studies are needed to evaluate the clinical significance of growth patterns in the tail ends of this distribution.

Antenatally Detected Congenital Pulmonary Airway Malformations: The Oxford Experience

Congenital airway pulmonary malformations are increasingly being diagnosed, but their management continues to remain controversial. Our approach has been to offer surgery to mitigate the risk of infection and possible malignancy. All patients routinely undergo a CT scan of the chest postnatally and once the diagnosis is confirmed, minimal access surgery is offered. Our anesthetists provide single-lung ventilation to enhance the operative view. We conducted a retrospective review over a 10-year period, during which 91 patients were prenatally suspected to have a cystic lung lesion. There were 88 live births of which 29 (33%) cases were initially managed conservatively based on CT findings. Five of these patients, however, became symptomatic needing surgery. A total of 64 (73%) patients underwent surgery with the most common lesions being congenital pulmonary airway malformations (CPAMs) (24), hybrid lesions (19), and pulmonary sequestrations (12). The median age at surgery was 5 months (1 day to 17 months). Using a minimal access approach, 41 (64%) cases were completed with 17 performed open from the onset. Open surgery was indicated in neonates who became symptomatic within the first few weeks of life as well as patients in respiratory distress that would not tolerate either single-lung ventilation or gas insufflation. There were six further conversions to open from minimal access surgery due to poor visualization or technical difficulties. One patient needed a perioperative blood transfusion and one patient had a more prolonged stay due to persistent air leak managed conservatively. Among asymptomatic patients, evidence of microscopic disease was seen, which included infection as well as two cases of tumors, one pleuropulmonary blastoma seen as part of a CPAM, and one rhabdomyomatous dysplasia seen in the CPAM component of a hybrid lesion. In our experience, excising asymptomatic lesions is safe with minimal complications. Single-lung ventilation in combination with thoracoscopy provides excellent vision. There is a risk of infection and a definite, albeit low, risk of malignancy, which may outweigh the benefits of conservative management.

3D fractional moving blood volume (3D-FMBV) demonstrates decreased first trimester placental vascularity in pre-eclampsia but not the term, small for gestation age baby

OBJECTIVE

To undertake an observational study to see whether first trimester placental vascularity, measured with a standardized power Doppler index: 3D-FMBV, is different in pregnancies which either develop pre-eclampsia or lead to term, normotensive small for gestational age (SGA) babies.

METHODS

Women were scanned between 11 and 13+6 weeks. The placental volume (sPlaV) was estimated using our previously validated semi-automated tool. Estimates of 3D-FMBV were generated from the raw power Doppler signal for the whole utero-placental interface, UPI (FMBV-UPI) and 5mm into the placenta (FMBV-IVS). Differences in the placental volume and FMBV for pregnancies developing pre-eclampsia and resulting in term, normotensive SGA babies were compared with term, normotensive, appropriate for gestational age (AGA), controls.

RESULTS

Results were available for 143 women. The placental volume (sPlaV) was reduced in both pre-eclampsia (p = 0.007) and term, normotensive SGA (p = 0.001) when compared with term normotensive AGA controls. 3D-FMBV estimates were significantly lower for pregnancies developing pre-eclampsia (FMBV-UPI, p = 0.03, FMBV-IVS, p = 0.01) but not for the normotensive SGA pregnancies (FMBV-UPI, p = 0.16, FMBV-IVS, p = 0.27).

CONCLUSION

Pregnancies destined to develop pre-eclampsia are more likely to have small placentas with significantly reduced vascularity at 11-13 weeks. Those pregnancies which were normotensive throughout but resulted in an SGA baby delivered at term, had significantly smaller placentas but with similar vascularity to normotensive AGA pregnancies.

3-D Ultrasound Segmentation of the Placenta Using the Random Walker Algorithm: Reliability and Agreement

Volumetric segmentation of the placenta using 3-D ultrasound is currently performed clinically to investigate correlation between organ volume and fetal outcome or pathology. Previously, interpolative or semi-automatic contour-based methodologies were used to provide volumetric results. We describe the validation of an original random walker (RW)-based algorithm against manual segmentation and an existing semi-automated method, virtual organ computer-aided analysis (VOCAL), using initialization time, inter- and intra-observer variability of volumetric measurements and quantification accuracy (with respect to manual segmentation) as metrics of success. Both semi-automatic methods require initialization. Therefore, the first experiment compared initialization times. Initialization was timed by one observer using 20 subjects. This revealed significant differences (p < 0.001) in time taken to initialize the VOCAL method compared with the RW method. In the second experiment, 10 subjects were used to analyze intra-/inter-observer variability between two observers. Bland-Altman plots were used to analyze variability combined with intra- and inter-observer variability measured by intra-class correlation coefficients, which were reported for all three methods. Intra-class correlation coefficient values for intra-observer variability were higher for the RW method than for VOCAL, and both were similar to manual segmentation. Inter-observer variability was 0.94 (0.88, 0.97), 0.91 (0.81, 0.95) and 0.80 (0.61, 0.90) for manual, RW and VOCAL, respectively. Finally, a third observer with no prior ultrasound experience was introduced and volumetric differences from manual segmentation were reported. Dice similarity coefficients for observers 1, 2 and 3 were respectively 0.84 ± 0.12, 0.94 ± 0.08 and 0.84 ± 0.11, and the mean was 0.87 ± 0.13. The RW algorithm was found to provide results concordant with those for manual segmentation and to outperform VOCAL in aspects of observer reliability. The training of an additional untrained observer was investigated, and results revealed that with the appropriate initialization protocol, results for observers with varying levels of experience were concordant. We found that with appropriate training, the RW method can be used for fast, repeatable 3-D measurement of placental volume.

Congenital lung lesions: Prenatal diagnosis and intervention

Congenital lung lesions are common sonographic findings in pregnancy, usually detected at the routine 20 weeks scan. The most common is cystic adenomatous malformation of the lung (CCAM). This usually causes few prenatal problems; however, fetal hydrops occurs in about 5%. Prenatal intervention for these is possible in many to allow survival to birth. Bronchoplumonary sequestration (BPS), with an aberrant "feeder" vessel arising from the aorta may co-exist but is detectable as a separate entity by visualization of this vessel. Symptomatic or curative prenatal intervention is again possible in the few severe cases where hydrops or pleural effusions develop. Pleural effusions may be due to a primary leak usually of chylous fluid: prenatal thoracoamniotic shunting may prevent pulmonary hyoplasia or cure the consequent fetal hydrops. More often, however, effusions are a consequence of an underlying abnormality, including many structural or chromosomal abnormalities that may also cause co-existing fetal hydrops. Congenital high airway obstruction (CHAOS) is commonly fatal but cases potentially amenable to prenatal intervention or to immediate perinatal management may be identified using ultrasound or MRI.

Comparison of 2-D and 3-D estimates of placental volume in early pregnancy

Ultrasound estimation of placental volume (PlaV) between 11 and 13 wk has been proposed as part of a screening test for small-for-gestational-age babies. A semi-automated 3-D technique, validated against the gold standard of manual delineation, has been found at this stage of gestation to predict small-for-gestational-age at term. Recently, when used in the third trimester, an estimate obtained using a 2-D technique was found to correlate with placental weight at delivery. Given its greater simplicity, the 2-D technique might be more useful as part of an early screening test. We investigated if the two techniques produced similar results when used in the first trimester. The correlation between PlaV values calculated by the two different techniques was assessed in 139 first-trimester placentas. The agreement on PlaV and derived "standardized placental volume," a dimensionless index correcting for gestational age, was explored with the Mann-Whitney test and Bland-Altman plots. Placentas were categorized into five different shape subtypes, and a subgroup analysis was performed. Agreement was poor for both PlaV and standardized PlaV (p < 0.001 and p < 0.001), with the 2-D technique yielding larger estimates for both indices compared with the 3-D method. The mean difference in standardized PlaV values between the two methods was 0.007 (95% confidence interval: 0.006-0.009). The best agreement was found for regular rectangle-shaped placentas (p = 0.438 and p = 0.408). The poor correlation between the 2-D and 3-D techniques may result from the heterogeneity of placental morphology at this stage of gestation. In early gestation, the simpler 2-D estimates of PlaV do not correlate strongly with those obtained with the validated 3-D technique.

Post-natal outcomes of antenatally diagnosed intra-abdominal cysts: a 22-year single-institution series

PURPOSE

The aim of this study was to establish the post-natal diagnosis and outcome of antenatally diagnosed intra-abdominal cysts between 1991 and 2013 at our institution.

METHODS

All antenatally diagnosed intra-abdominal cysts between 1991 and 2013 were identified using a foetal anomaly database. The cysts were monitored for resolution. In all cases where the cyst had not resolved antenatally, additional post-natal scans were conducted. Antenatal diagnosis, post-natal diagnosis and outcomes were also recorded.

RESULTS

118 cases of antenatal intra-abdominal cysts were identified over the 22-year study period with a 98 % live birth rate. The overall accuracy of an antenatal diagnosis at our institution was 92 %. 26 cases (22 %) resolved spontaneously in utero, the majority of which (77 %) were ovarian in nature. Four tumour cases were identified in the series, which included two neuroblastomas, one yolk sac tumour and one teratoma. 90 cysts persisted post-natally with 52 % requiring surgery. These primarily included choledochal and enteric duplication cysts as well as symptomatic solid organ cysts. Diagnostic revision was limited to 8 % of cases over the study period with an overall improvement over the last decade. Overall, 40 % of all antenatally diagnosed cysts required surgical intervention. In those cysts that persisted post-natally, 52 % required surgery.

CONCLUSIONS

A fifth of prenatally diagnosed intra-abdominal cysts will resolve with most ovarian cysts regressing in utero. Half of all persistent cysts will, however, require surgical intervention. These data are useful for prenatal counselling and demonstrates the important role played by the paediatric surgeon in the overall management of intra-abdominal cysts.