The Role of cfDNA Biomarkers and Patient Data in the Early Prediction of Preeclampsia: Artificial Intelligence Model.

OBJECTIVE: Accurate individualized assessment of preeclampsia risk enables the identification of patients most likely to benefit from initiation of low-dose aspirin at 12-16 weeks' gestation when there is evidence for its effectiveness, as well as guiding appropriate pregnancy care pathways and surveillance. The primary objective of this study was to evaluate the performance of artificial neural network models for the prediction of preterm preeclampsia (<37 weeks' gestation) using patient characteristics available at the first antenatal visit and data from prenatal cell-free DNA (cfDNA) screening. Secondary outcomes were prediction of early onset preeclampsia (<34 weeks' gestation) and term preeclampsia (≥37 weeks' gestation). METHODS: This secondary analysis of a prospective, multicenter, observational prenatal cfDNA screening study (SMART) included singleton pregnancies with known pregnancy outcomes. Thirteen patient characteristics that are routinely collected at the first prenatal visit and two characteristics of cfDNA, total cfDNA and fetal fraction (FF), were used to develop predictive models for early-onset (<34 weeks), preterm (<37 weeks), and term (≥37 weeks) preeclampsia. For the models, the 'reference' classifier was a shallow logistic regression (LR) model. We also explored several feedforward (non-linear) neural network (NN) architectures with one or more hidden layers and compared their performance with the LR model. We selected a simple NN model built with one hidden layer and made up of 15 units. RESULTS: Of 17,520 participants included in the final analysis, 72 (0.4%) developed early onset, 251 (1.4%) preterm, and 420 (2.4%) term preeclampsia. Median gestational age at cfDNA measurement was 12.6 weeks and 2,155 (12.3%) had their cfDNA measurement at 16 weeks' gestation or greater. Preeclampsia was associated with higher total cfDNA (median 362.3 versus 339.0 copies/ml cfDNA; p<0.001) and lower FF (median 7.5% versus 9.4%; p<0.001). The expected, cross-validated area under the curve (AUC) scores for early onset, preterm, and term preeclampsia were 0.782, 0.801, and 0.712, respectively for the LR model, and 0.797, 0.800, and 0.713, respectively for the NN model. At a screen-positive rate of 15%, sensitivity for preterm preeclampsia was 58.4% (95% CI 0.569, 0.599) for the LR model and 59.3% (95% CI 0.578, 0.608) for the NN model.The contribution of both total cfDNA and FF to the prediction of term and preterm preeclampsia was negligible. For early-onset preeclampsia, removal of the total cfDNA and FF features from the NN model was associated with a 6.9% decrease in sensitivity at a 15% screen positive rate, from 54.9% (95% CI 52.9-56.9) to 48.0% (95% CI 45.0-51.0). CONCLUSION: Routinely available patient characteristics and cfDNA markers can be used to predict preeclampsia with performance comparable to other patient characteristic models for the prediction of preterm preeclampsia. Both LR and NN models showed similar performance.

Redesigning antenatal care: Prospective use of an implementation framework to establish a population-based multidisciplinary first-trimester screening, assessment and prevention service.

BACKGROUND: Australian rates of adverse obstetric outcomes have improved little despite guidelines recommending history-based screening and intervention. The first trimester provides a unique opportunity to predict and prevent complications, yet population-based screening has failed to be translated into broad clinical practice. AIMS: This study aimed to redesign antenatal care within an Australian public healthcare centre to align with evidence-based maternity care, including population-based first-trimester screening with early initiation of preventative strategies in high-risk pregnancies. METHODS: A five-phase action-process model, sharing key elements with implementation science theory, was used to explore barriers to change in antenatal care, co-design a novel service with consumers and establish a population-based antenatal pathway commencing with a multidisciplinary first-trimester screening, assessment and planning visit. RESULTS: The case for change and associated barriers were defined from the perspective of antenatal care stakeholders. Key needs of each group were established, and solutions were created using co-design methodology, allowing the team to create a novel approach to antenatal care which directly addressed identified barriers. Implementation of the service was associated with a fall in the median gestation at first specialist maternity care provider visit from 20 to 13 weeks. CONCLUSIONS: This study confirms the feasibility of establishing a comprehensive first-trimester screening program within a public Australian healthcare setting and highlights a co-design process which places individualised assessment at the forefront of antenatal care. This framework may be applicable to most public maternity settings in Australia, with expansion aimed at providing equity of care, including in rural and remote settings.

Performance of prenatal cfDNA screening for sex chromosomes.

PURPOSE: The aim of this study was to assess the performance of cell-free DNA (cfDNA) screening to detect sex chromosome aneuploidies (SCAs) in an unselected obstetrical population with genetic confirmation. METHODS: This was a planned secondary analysis of the multicenter, prospective SNP-based Microdeletion and Aneuploidy RegisTry (SMART) study. Patients receiving cfDNA results for autosomal aneuploidies and who had confirmatory genetic results for the relevant sex chromosomal aneuploidies were included. Screening performance for SCAs, including monosomy X (MX) and the sex chromosome trisomies (SCT: 47,XXX; 47,XXY; 47,XYY) was determined. Fetal sex concordance between cfDNA and genetic screening was also evaluated in euploid pregnancies. RESULTS: A total of 17,538 cases met inclusion criteria. Performance of cfDNA for MX, SCTs, and fetal sex was determined in 17,297, 10,333, and 14,486 pregnancies, respectively. Sensitivity, specificity, and positive predictive value (PPV) of cfDNA were 83.3%, 99.9%, and 22.7% for MX and 70.4%, 99.9%, and 82.6%, respectively, for the combined SCTs. The accuracy of fetal sex prediction by cfDNA was 100%. CONCLUSION: Screening performance of cfDNA for SCAs is comparable to that reported in other studies. The PPV for the SCTs was similar to the autosomal trisomies, whereas the PPV for MX was substantially lower. No discordance in fetal sex was observed between cfDNA and postnatal genetic screening in euploid pregnancies. These data will assist interpretation and counseling for cfDNA results for sex chromosomes.

Obstetrical, perinatal, and genetic outcomes associated with nonreportable prenatal cell-free DNA screening results.

BACKGROUND: The clinical implications of nonreportable cell-free DNA screening results are uncertain, but such results may indicate poor placental implantation in some cases and be associated with adverse obstetrical and perinatal outcomes. OBJECTIVE: This study aimed to assess the outcomes of pregnancies with nonreportable cell-free DNA screening in a cohort of patients with complete genetic and obstetrical outcomes. STUDY DESIGN: This was a prespecified secondary analysis of a multicenter prospective observational study of prenatal cell-free DNA screening for fetal aneuploidy and 22q11.2 deletion syndrome. Participants who underwent cell-free DNA screening from April 2015 through January 2019 were offered participation. Obstetrical outcomes and neonatal genetic testing results were collected from 21 primary-care and referral centers in the United States, Europe, and Australia. The primary outcome was risk for adverse obstetrical and perinatal outcomes (aneuploidy, preterm birth at <28, <34, and <37 weeks' gestation, preeclampsia, small for gestational age or birthweight <10th percentile for gestational week, and a composite outcome that included preterm birth at <37 weeks, preeclampsia, small for gestational age, and stillbirth at >20 weeks) after nonreportable cell-free DNA screening because of low fetal fraction or other causes. Multivariable analyses were performed, adjusting for variables known to be associated with obstetrical and perinatal outcomes, nonreportable results, or fetal fraction. RESULTS: In total, 25,199 pregnant individuals were screened, and 20,194 were enrolled. Genetic confirmation was missing in 1165 (5.8%), 1085 (5.4%) were lost to follow-up, and 93 (0.5%) withdrew; the final study cohort included 17,851 (88.4%) participants who had cell-free DNA, fetal or newborn genetic confirmatory testing, and obstetrical and perinatal outcomes collected. Results were nonreportable in 602 (3.4%) participants. A sample was redrawn and testing attempted again in 427; in 112 (26.2%) participants, results were again nonreportable. Nonreportable results were associated with higher body mass index, chronic hypertension, later gestational age, lower fetal fraction, and Black race. Trisomy 13, 18, or 21 was confirmed in 1.6% with nonreportable tests vs 0.7% with reported results (P=.013). Rates of preterm birth at <28, 34, and 37 weeks, preeclampsia, and the composite outcome were higher among participants with nonreportable results, and further increased among those with a second nonreportable test, whereas the rate of small for gestational age infants was not increased. After adjustment for confounders, the adjusted odds ratios were 2.2 (95% confidence interval, 1.1-4.4) and 2.6 (95% confidence interval, 0.6-10.8) for aneuploidy, and 1.5 (95% confidence interval, 1.2-1.8) and 2.1 (95% confidence interval, 1.4-3.2) for the composite outcome after a first and second nonreportable test, respectively. Of the patients with nonreportable tests, 94.9% had a live birth, as opposed to 98.8% of those with reported test results (adjusted odds ratio for livebirth, 0.20 [95% confidence interval, 0.13-0.30]). CONCLUSION: Patients with nonreportable cell-free DNA results are at increased risk for a number of adverse outcomes, including aneuploidy, preeclampsia, and preterm birth. They should be offered diagnostic genetic testing, and clinicians should be aware of the increased risk of pregnancy complications.

Do first-trimester screening algorithms for preeclampsia aligned to use of preventative therapies reduce the prevalence of pre-term preeclampsia: A systematic review and meta-analysis.

OBJECTIVE: Traditional obstetric practice relies upon history-based assessment to screen for preeclampsia and guide preventative therapies but is hampered by low sensitivity, high false-positive rates and low treatment rates. First-trimester screening algorithms represent the most efficacious approach for risk prediction and could target early initiation of aspirin to well-defined high-risk populations. A large randomised controlled trial has demonstrated the clinical benefits of this approach, but widespread practice implementation has remained elusive. METHODS: We performed a systematic review and meta-analysis summarising studies linking first-trimester preeclampsia screening algorithms with the initiation of preventative therapy and examined their effect on pre-term preeclampsia rates compared with standard maternity care. Odds ratios were calculated together with 95% confidence intervals. RESULTS: 7 studies with a total of 377,790 participants were included. Within singleton populations, early initiation of aspirin in response to a high-risk screening algorithm result reduced the prevalence of pre-term preeclampsia by 39% compared with routine antenatal care (odds ratio 0.61; 95% CI: 0.52-0.70). There were significant reductions in the prevalence of preeclampsia at <32-34 weeks, preeclampsia at any gestation and stillbirth. CONCLUSION: First-trimester screening algorithms for preeclampsia aligned with early initiation of preventative therapy with aspirin reduce the prevalence of pre-term preeclampsia.

Impact of high-risk prenatal screening results for 22q11.2 deletion syndrome on obstetric and neonatal management: Secondary analysis from the SMART study.

OBJECTIVE: One goal of prenatal genetic screening is to optimize perinatal care and improve infant outcomes. We sought to determine whether high-risk cfDNA screening for 22q11.2 deletion syndrome (22q11.2DS) affected prenatal or neonatal management. METHODS: This was a secondary analysis from the SMART study. Patients with high-risk cfDNA results for 22q11.2DS were compared with the low-risk cohort for pregnancy characteristics and obstetrical management. To assess differences in neonatal care, we compared high-risk neonates without prenatal genetic confirmation with a 1:1 matched low-risk cohort. RESULTS: Of 18,020 eligible participants enrolled between 2015 and 2019, 38 (0.21%) were high-risk and 17,982 (99.79%) were low-risk for 22q11.2DS by cfDNA screening. High-risk participants had more prenatal diagnostic testing (55.3%; 21/38 vs. 2.0%; 352/17,982, p < 0.001) and fetal echocardiography (76.9%; 10/13 vs. 19.6%; 10/51, p < 0.001). High-risk newborns without prenatal diagnostic testing had higher rates of neonatal genetic testing (46.2%; 6/13 vs. 0%; 0/51, P < 0.001), echocardiography (30.8%; 4/13 vs. 4.0%; 2/50, p = 0.013), evaluation of calcium levels (46.2%; 6/13 vs. 4.1%; 2/49, P < 0.001) and lymphocyte count (53.8%; 7/13 vs. 15.7%; 8/51, p = 0.008). CONCLUSIONS: High-risk screening results for 22q11.2DS were associated with higher rates of prenatal and neonatal diagnostic genetic testing and other 22q11.2DS-specific evaluations. However, these interventions were not universally performed, and >50% of high-risk infants were discharged without genetic testing, representing possible missed opportunities to improve outcomes for affected individuals.

Cell-free DNA screening for prenatal detection of 22q11.2 deletion syndrome.

BACKGROUND: Historically, prenatal screening has focused primarily on the detection of fetal aneuploidies. Cell-free DNA now enables noninvasive screening for subchromosomal copy number variants, including 22q11.2 deletion syndrome (or DiGeorge syndrome), which is the most common microdeletion and a leading cause of congenital heart defects and neurodevelopmental delay. Although smaller studies have demonstrated the feasibility of screening for 22q11.2 deletion syndrome, large cohort studies with confirmatory postnatal testing to assess test performance have not been reported. OBJECTIVE: This study aimed to assess the performance of single-nucleotide polymorphism-based, prenatal cell-free DNA screening for detection of 22q11.2 deletion syndrome. STUDY DESIGN: Patients who underwent single-nucleotide polymorphism-based prenatal cell-free DNA screening for 22q11.2 deletion syndrome were prospectively enrolled at 21 centers in 6 countries. Prenatal or newborn DNA samples were requested in all cases for genetic confirmation using chromosomal microarrays. The primary outcome was sensitivity, specificity, positive predictive value, and negative predictive value of cell-free DNA screening for the detection of all deletions, including the classical deletion and nested deletions that are ≥500 kb, in the 22q11.2 low-copy repeat A-D region. Secondary outcomes included the prevalence of 22q11.2 deletion syndrome and performance of an updated cell-free DNA algorithm that was evaluated with blinding to the pregnancy outcome. RESULTS: Of the 20,887 women enrolled, a genetic outcome was available for 18,289 (87.6%). A total of 12 22q11.2 deletion syndrome cases were confirmed in the cohort, including 5 (41.7%) nested deletions, yielding a prevalence of 1 in 1524. In the total cohort, cell-free DNA screening identified 17,976 (98.3%) cases as low risk for 22q11.2 deletion syndrome and 38 (0.2%) cases as high risk; 275 (1.5%) cases were nonreportable. Overall, 9 of 12 cases of 22q11.2 were detected, yielding a sensitivity of 75.0% (95% confidence interval, 42.8-94.5); specificity of 99.84% (95% confidence interval, 99.77-99.89); positive predictive value of 23.7% (95% confidence interval, 11.44-40.24), and negative predictive value of 99.98% (95% confidence interval, 99.95-100). None of the cases with a nonreportable result was diagnosed with 22q11.2 deletion syndrome. The updated algorithm detected 10 of 12 cases (83.3%; 95% confidence interval, 51.6-97.9) with a lower false positive rate (0.05% vs 0.16%; P<.001) and a positive predictive value of 52.6% (10/19; 95% confidence interval, 28.9-75.6). CONCLUSION: Noninvasive cell-free DNA prenatal screening for 22q11.2 deletion syndrome can detect most affected cases, including smaller nested deletions, with a low false positive rate.

Cell-free DNA screening for trisomies 21, 18, and 13 in pregnancies at low and high risk for aneuploidy with genetic confirmation.

BACKGROUND: Cell-free DNA noninvasive prenatal screening for trisomies 21, 18, and 13 has been rapidly adopted into clinical practice. However, previous studies are limited by a lack of follow-up genetic testing to confirm the outcomes and accurately assess test performance, particularly in women at a low risk for aneuploidy. OBJECTIVE: To measure and compare the performance of cell-free DNA screening for trisomies 21, 18, and 13 between women at a low and high risk for aneuploidy in a large, prospective cohort with genetic confirmation of results STUDY DESIGN: This was a multicenter prospective observational study at 21 centers in 6 countries. Women who had single-nucleotide-polymorphism-based cell-free DNA screening for trisomies 21, 18, and 13 were enrolled. Genetic confirmation was obtained from prenatal or newborn DNA samples. The test performance and test failure (no-call) rates were assessed for the cohort, and women with low and high previous risks for aneuploidy were compared. An updated cell-free DNA algorithm blinded to the pregnancy outcome was also assessed. RESULTS: A total of 20,194 women were enrolled at a median gestational age of 12.6 weeks (interquartile range, 11.6-13.9). The genetic outcomes were confirmed in 17,851 cases (88.4%): 13,043 (73.1%) low-risk and 4808 (26.9%) high-risk cases for aneuploidy. Overall, 133 trisomies were diagnosed (100 trisomy 21; 18 trisomy 18; 15 trisomy 13). The cell-free DNA screen positive rate was lower in the low-risk vs the high-risk group (0.27% vs 2.2%; P<.0001). The sensitivity and specificity were similar between the groups. The positive predictive value for the low- and high-risk groups was 85.7% vs 97.5%; P=.058 for trisomy 21; 50.0% vs 81.3%; P=.283 for trisomy 18; and 62.5% vs 83.3; P=.58 for trisomy 13, respectively. Overall, 602 (3.4%) patients had no-call result after the first draw and 287 (1.61%) after including cases with a second draw. The trisomy rate was higher in the 287 cases with no-call results than patients with a result on a first draw (2.8% vs 0.7%; P=.001). The updated algorithm showed similar sensitivity and specificity to the study algorithm with a lower no-call rate. CONCLUSION: In women at a low risk for aneuploidy, single-nucleotide-polymorphism-based cell-free DNA has high sensitivity and specificity, positive predictive value of 85.7% for trisomy 21 and 74.3% for the 3 common trisomies. Patients who receive a no-call result are at an increased risk of aneuploidy and require additional investigation.

Extracellular Vesicles and Preeclampsia: Current Knowledge and Future Research Directions.

Preeclampsia (PE) is associated with long-term morbidity in mothers and lifelong morbidities for their children, ranging from cerebral palsy and cognitive delay in preterm infants, to hypertension, diabetes and obesity in adolescents and young adults. There are several processes that are critical for development of materno-fetal exchange, including establishing adequate perfusion of the placenta by maternal blood, and the formation of the placental villous vascular tree. Recent studies provide persuasive evidence that placenta-derived extracellular vesicles (EVs) represent a significant intercellular communication pathway, and that they may play an important role in placental and endothelial cell (both fetal and maternal) function. These functions are known to be altered in PE. EVs can carry and transport a wide range of bioactive molescules that have potential to be used as biomarkers and therapeutic delivery tools for PE. EV content is often parent cell specific, thus providing an insight or "thumbprint" of the intracellular environment of the originating cell (e.g., human placenta). EV have been identified in plasma under both normal and pathological conditions, including PE. The concentration of EVs and their content in plasma has been reported to increase in association with disease severity and/or progression. Placenta-derived EVs have been identified in maternal plasma during normal pregnancy and PE pregnancies. They contain placenta-specific proteins and miRNAs and, as such, may be differentiated from maternally-derived EVs. The aim of this review, thus, is to describe the potential roles of EVs in preecmpatic pregnancies, focussing on EVs secreted from placental cells. The biogenesis, specificity of placental EVs, and methods used to characterise EVs in the context of PE pregnancies will be also discussed.

Interventions for the Prevention of Preterm Premature Rupture of Membranes: A Systematic Review and Meta-Analysis.

INTRODUCTION: Preterm prelabour rupture of membranes (PPRoM) is a significant cause of maternal and perinatal morbidity and mortality. The aim of this project was to identify interventions that reduce the prevalence of PPRoM. METHODS: Search strategy included a systematic literature search of MEDLINE, EMBASE, PubMed, and Cochrane Library. The selection criteria included randomized control studies that compared a therapy to standard care (no therapy or placebo) in pregnancy and included PPRoM as an outcome. Risk of bias was assessed according to the Cochrane risk-of-bias tool for randomized trials. Odds ratios with 95% confidence intervals were calculated using random-effects models. Quality of evidence was assessed using the GRADE methodology. RESULTS: Twenty-nine studies examining 10 interventions met the inclusion criteria. Therapies included docosahexaenoic acid (DHA), aspirin, rofecoxib, vitamin C alone and with vitamin E, folic acid (alone, with iron, with iron and zinc, within a multiple micronutrient supplement), zinc, calcium, copper, and treatment of bacterial vaginosis. There was no significant difference in the prevalence of PPRoM in the treatment groups compared to placebo, except for rofecoxib which showed an increased risk of PPRoM (RR 2.46, 95% CI 1.28-4.73; p = 0.007, 1 trial, 98 women; very low quality of evidence) and a multiple micronutrient supplement which showed a reduction in PPRoM (RR 0.40, 95% CI 0.19-0.84; p = 0.01, 1 trial, 1,671 women; very low quality of evidence). CONCLUSIONS: No interventions have been convincingly shown to reduce the prevalence of PPRoM. Given this is a common problem leading to significant morbidity and mortality, further research is required.

A hospital-based cohort study of gender and gestational age-specific body fat percentage at birth.

BACKGROUND: Birthweight is the most commonly used proxy marker but does not adequately define true nutritional status. Modalities like DXA (dual energy x-ray absorptiometry) and TOtal Body Electric Conductivity (TOBEC) have been validated to assess body composition but their accuracy in neonates has not been established. The PEAPOD (COSMED, Rome Italy) has been validated as an accurate tool for measuring percentage body fat (%BF) in newborns. The study aim was to determine the gender-specific %BF percentiles at different gestations (35-41 weeks) for a healthy population of newborn infants. A secondary aim was to determine whether there is any relationship between %BF and neonatal condition at birth (cord gas measurement). METHODS: %BF was measured using air displacement plethysmography (PEAPOD) within 6 h of birth. RESULTS: There is an increase in the mean %BF with increasing gestation for female and males from 36 weeks' gestation in the 7667 infants who underwent assessment. Females have a higher %BF than their male equivalents. There was no correlation between %BF and cord pH. CONCLUSION: Gender and gestation are both important in determining the quantiles and mean %BF at birth. There was no correlation between low cord pH and %BF. IMPACT: Measuring the percentage body fat (PEAPOD) at birth is a useful marker of an infant's nutritional status. This is the largest hospital-based cohort of gestational age and gender-specific %BF in healthy newborns. The normative graphs from this study will help to accurately determine high-risk infants with low %BF so they can be monitored appropriately.

Does aspirin prescribed to women deemed high risk for preterm pre-eclampsia at 11-13+6 weeks gestation affect the prevalence of small for gestational age neonates?

BACKGROUND: Aspirin has been shown to reduce prevalence of both early-onset pre-eclampsia (ePET) and fetal growth restriction (FGR). AIMS: To determine whether aspirin prescribed for risk of ePET reduces the prevalence of small for gestational age (SGA) neonates. MATERIAL AND METHODS: Two prospective cohorts were consecutively recruited in a large university hospital in Sydney. The Observational cohort (April 2010 to March 2012) validated an algorithm for ePET screening, where risk for ePET was modelled on history, mean arterial pressure, uterine artery pulsatility index and pregnancy-associated plasma protein A. The Interventional cohort (April 2012 to December 2017) were screened and allocated women at high risk of developing ePET to aspirin 150 mg. The prevalence of preterm and term SGA was compared using regression analysis. RESULT: There were 3013 and 8424 women screened in the Observational and Interventional cohorts respectively. Women who screened high risk for ePET were three to four times more likely to give birth to a neonate classified as SGA in the Observational (6.8% vs 1.9%) and Interventional cohorts (6.0% vs 1.8%). In women who screened high risk, there were no statistically significant differences in the prevalence of SGA neonates (6.6% vs 6.0%; adjusted odds ratio 0.84 (0.50-1.42)) in women who received aspirin compared to women who did not. CONCLUSIONS: Women who screen high risk for ePET have an increased chance of delivering an SGA infant. A reduction in the prevalence of SGA neonates when aspirin was prescribed to women who screened high risk for ePET did not reach clinical significance in our cohort.

A survey of obstetricians' attitudes to induction of labour at 39 weeks gestation with the intention of reducing caesarean section rates.

BACKGROUND: Induction of labour (IOL) and caesarean section (CS) rates continue to increase in Australia, New Zealand and globally. There is evidence that CS rates are decreased in the context of medically indicated and elective IOL; therefore, the emerging concept of using IOL as means of preventing CS warrants investigation. AIMS: To assess obstetricians' opinions of elective IOL at 39 weeks gestation, its feasibility, generalisability and utility as a means of preventing CS in Australia and New Zealand. MATERIALS AND METHODS: A de-identified cross-sectional survey was distributed electronically to all Fellows and trainees of The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). The survey was voluntary and distributed with the approval of the RANZCOG Continuing Education Committee. The survey addressed opinions relating to rates of and indications for IOL, the perceived validity of those indications and explored the acceptability of using a screening tool to predict women at increased risk of intra-partum CS and tailoring obstetric management to include the option of IOL at 39 weeks gestation. RESULTS: The overall response rate was 34% (492/1423) (including trainees) and the response rate was 53% (394/750) for currently practising obstetricians. The majority (90%) of responders agreed on medical and clinical indications for IOL. There was no consensus on the validity of IOL if a woman were at apparent high risk of intra-partum CS; however, 81% (360/443) of clinicians would be interested in a tool that could predict those women at risk. CONCLUSIONS: There is heterogeneity of obstetrician's beliefs on using IOL at 39 weeks as a mechanism to reduce the CS rate.

Measured Hyperelastic Properties of Cervical Tissue with Shear-Wave Elastography.

The nonlinear mechanical behaviour of cervical tissue causes unpredictable changes in measured elastograms when pressure is applied. These uncontrolled variables prevent the reliable measurement of tissue elasticity in a clinical setting. Measuring the nonlinear properties of tissue is difficult due to the need for both shear modulus and strain to be taken simultaneously. A simulation-based method is proposed in this paper to resolve this. This study describes the nonlinear behaviour of cervical tissue using the hyperelastic material models of Demiray-Fung and Veronda-Westmann. Elastograms from 33 low-risk patients between 18 and 22 weeks gestation were obtained. The average measured properties of the hyperelastic material models are: Demiray-Fung-A1α = 2.07 (1.65-2.58) kPa, α = 6.74 (4.07-19.55); Veronda-Westmann-C1C2 = 4.12 (3.24-5.04) kPa, C2 = 4.86 (2.86-14.28). The Demiray-Fung and Veronda-Westmann models performed similarly in fitting to the elastograms with an average root mean square deviation of 0.41 and 0.47 ms-1, respectively. The use of hyperelastic material models to calibrate shear-wave speed measurements improved the consistency of measurements. This method could be applied in a large-scale clinical setting but requires updated models and higher data resolution.

Placental Growth Factor and Adverse Obstetric Outcomes in a Mixed-Risk Cohort of Women Screened for Preeclampsia in the First Trimester of Pregnancy.

OBJECTIVE: The study aimed to investigate the association between placental growth factor (PlGF) and adverse obstetric outcomes in a mixed-risk cohort of pregnant women screened for preeclampsia (PE) in the first trimester. METHODS: We included women with singleton pregnancies screened for PE between April 2014 and September 2016. Outcome data were retrieved from the New South Wales Perinatal Data Collection (NSW PDC) by linkage to the prenatal cohort. Adverse outcomes were defined as spontaneous preterm birth (sPTB) before 37-week gestation, birth weight (BW) below the 3rd centile, PE, gestational hypertension (GH), stillbirth, and neonatal death. RESULTS: The cohort consisted of 11,758 women. PlGF multiple of the median (MoM) was significantly associated with maternal sociodemographic characteristics (particularly smoking status and parity) and all biomarkers used in the PE first trimester screening model (notably pregnancy-associated plasma protein A MoM and uterine artery pulsatility index [PI] MoM). Low levels of PlGF (<0.3 MoM and <0.5 MoM) were independently associated with sPTB, low BW, PE, GH, and a composite adverse pregnancy outcome score, with odds ratios between 1.81 and 4.44 on multivariable logistic regression analyses. CONCLUSIONS: Low PlGF MoM levels are independently associated with PE and a range of other adverse pregnancy outcomes. Inclusion of PlGF should be considered in future models screening for adverse pregnancy outcomes in the first trimester.

Prediction of Birth Weight and Neonatal Adiposity Using Ultrasound Assessment of Soft Tissue Parameters in Addition to Two-Dimensional Conventional Biometry.

INTRODUCTION: We aim to evaluate the supplementary predictive value of soft tissue markers, including fetal limb volumes, for fetal birth weight and fat tissue weight. METHODS: This is a prospective study of 60 patients undergoing term induction of labor. Ultrasound was performed 48 h before birth, and 2D sonographic measurements, subcutaneous tissue thickness, and 3D fetal limb volumes were taken. Birth weight and neonatal fat weight were assessed by plethysmography. Clinical data were collected. The relation between ultrasound and neonatal outcomes was assessed by univariate and multivariate predictive models. The estimated and actual birth weights were compared applying different published formulas, and systematic and random error were collected and compared. RESULTS: 3D fetal limb volumes showed a strong relation to birth weight, absolute weight, and relative fat weight. The Lee 6 formula performed better than either Hadlock 3 or Lee 3 with the lowest random error. Fractional limb volumes involve a highly reproducible technique, with excellent correlation (intra-class coefficient >0.90) for both inter- and intra-observer reliability. The prevalence of estimated EFW measures within 10% error from the actual birth weight was 71.7% with the Hadlock 3 model and 95.0% with the Lee 6 model (p = 0.09). CONCLUSION: Late assessment of 3D fetal limb volume in upper and lower extremities is not only useful for accurately predicting birth weight but is a useful marker for prediction of birth fat tissue weight.

Consensus on Training and Assessment of Competence in Performing Chorionic Villus Sampling and Amniocentesis: An International Delphi Survey.

INTRODUCTION: The aim of this study was to obtain expert consensus on the content of a curriculum for learning chorionic villus sampling (CVS) and amniocentesis (AC) and the items of an assessment tool to evaluate CVS and AC competence. METHODS: We used a 3-round iterative Delphi process. A steering committee supervised all processes. Seven international collaborators were identified to expand the breadth of the study internationally. The collaborators invited fetal medicine experts to participate as panelists. In the first round, the panelists suggested content for a CVS/AC curriculum and an assessment tool. The steering committee organized and condensed the suggested items and presented them to the panelists in round 2. In the second round, the panelists rated and commented on the suggested items. The results were processed by the steering committee and presented to the panelists in the third round, where final consensus was obtained. Consensus was defined as support by more than 80% of the panelists for an item. RESULTS: Eighty-six experts agreed to participate in the study. The panelists represented 16 countries across 4 continents. The final list of curricular content included 12 theoretical and practical items. The final assessment tool included 11 items, systematically divided into 5 categories: pre-procedure, procedure, post-procedure, nontechnical skills, and overall performance. These items were provided with behavioral scale anchors to rate performance, and an entrustment scale was used for the final overall assessment. CONCLUSION: We established consensus among international fetal medicine experts on content to be included in a CVS/AC curriculum and on an assessment tool to evaluate CVS/AC skills. These results are important to help transition current training and assessment methods from a time- and volume-based approach to a competency-based approach which is a key step in improving patient safety and outcomes for the 2 most common invasive procedures in fetal medicine.

Hypoxia-induced small extracellular vesicle proteins regulate proinflammatory cytokines and systemic blood pressure in pregnant rats.

Small extracellular vesicles (sEVs) released from the extravillous trophoblast (EVT) are known to regulate uterine spiral artery remodeling during early pregnancy. The bioactivity and release of these sEVs differ under differing oxygen tensions and in aberrant pregnancy conditions. Whether the placental cell-derived sEVs released from the hypoxic placenta contribute to the pathophysiology of preeclampsia is not known. We hypothesize that, in response to low oxygen tension, the EVT packages a specific set of proteins in sEVs and that these released sEVs interact with endothelial cells to induce inflammation and increase maternal systemic blood pressure. Using a quantitative MS/MS approach, we identified 507 differentially abundant proteins within sEVs isolated from HTR-8/SVneo cells (a commonly used EVT model) cultured at 1% (hypoxia) compared with 8% (normoxia) oxygen. Among these differentially abundant proteins, 206 were up-regulated and 301 were down-regulated (P < 0.05), and they were mainly implicated in inflammation-related pathways. In vitro incubation of hypoxic sEVs with endothelial cells, significantly increased (P < 0.05) the release of GM-CSF, IL-6, IL-8, and VEGF, when compared with control (i.e. cells without sEVs) and normoxic sEVs. In vivo injection of hypoxic sEVs into pregnant rats significantly increased (P < 0.05) mean arterial pressure with increases in systolic and diastolic blood pressures. We propose that oxygen tension regulates the release and bioactivity of sEVs from EVT and that these sEVs regulate inflammation and maternal systemic blood pressure. This novel oxygen-responsive, sEVs signaling pathway, therefore, may contribute to the physiopathology of preeclampsia.

Cesarean delivery: Trend in indications over three decades within a major city hospital network.

INTRODUCTION: The cesarean delivery rate has been increasing globally in recent decades. The reasons for this are complex and subject to ongoing debate. Investigation of the indications for cesarean delivery and how these have changed over an extended period of time could provide insight into the reasons for changing obstetric practice. Our objective was to explore contributing factors to the increasing rate of cesarean delivery by examining the incidence of and indications for cesarean delivery over the past three decades at our institutions. MATERIAL AND METHODS: We conducted a retrospective observational study of all cesarean deliveries, from 24 weeks' gestational age onwards, within an inner-city hospital network in Sydney, Australia, between August 1989 and December 2016. The primary outcome measures were the rates of and indications for emergency and planned cesarean delivery. We also examined our data within the Robson 10-Group Classification system. RESULTS: There were 147 722 births over the study period, with 37 309 cesarean deliveries for an overall rate of 25.3%. The rate of cesarean delivery increased from 18.7% in 1989-1994 (8.7% emergency, 10% planned) to 30.4% in 2010-2016 (11.4% emergency, 19% planned). Emergency cesarean delivery for slow progress increased from 3.4% to 5.5% of all births (a relative increase of 62%) and other emergency cesareans mainly performed for suspected intrapartum fetal compromise increased from 5.2% to 5.6% (a relative increase of 8%). Previous uterine surgery (predominantly cesarean section) was the largest contributor to the increase in planned procedures from 3.8% to 9.0% of all births, and 29% of all cesarean deliveries. Primary cesarean delivery for planned antenatal fetal indications, previous pregnancy problems, multiple gestation and maternal choice all increased substantially in combined rate from 0.7% to 4.9%. Cesarean rates in Robson groups 6, 7 and 8 (term breech and multiple gestations) increased most over time. CONCLUSIONS: The increased rate of cesarean delivery is mainly attributable to a greater number of procedures performed for slow progress in labor, breech presentation or repeat cesarean section.

Influence of maternal and placental factors on newborn body composition.

AIM: The objective of this study was to assess whether maternal characteristics, placental size or histological chorioamnionitis was associated with newborn body composition. Furthermore, we sought to determine whether placental weight may mediate the association between maternal pre-pregnancy weight and age with newborn body composition. METHODS: A cross-sectional study was conducted at Royal Prince Alfred Hospital, Sydney, Australia. This study included 136 healthy, singleton, term-born newborns. Recruitment was stratified by newborn body fat percentiles (gender and gestational adjusted). Body fat was assessed by air displacement plethysmography. Placental examination was conducted by an anatomical pathologist. Maternal (chorioamnionitis) and fetal (chorionic and umbilical vasculitis, funisitis) inflammatory responses were classified according to Redline criteria. RESULTS: Maternal pre-pregnancy weight, parity, labour, placental weight and surface area were associated with newborn fat mass and fat-free mass. Gestational diabetes and maternal age were associated with newborn fat mass but not fat-free mass. There was no association between histological chorioamnionitis and newborn body composition; however, spontaneous onset of labour was strongly associated with the presence of histological chorioamnionitis. Only 25-31% of the association of maternal weight and age with newborn fat mass was mediated via the placenta. CONCLUSIONS: Maternal factors associated with newborn fat mass and fat-free mass differed, indicating that different mechanisms control fat mass and fat-free mass. Our mediation analysis suggests that placental weight partly mediates the association of maternal factors with newborn body composition. Histological chorioamnionitis was not associated with newborn body composition.