Centrality of the umbilical cord insertion in a human placenta influences the placental efficiency

Umbilical Cord Abnormalities

The umbilical cord is the connection between mother and fetus through which gases and nutrients are exchanged. It's remarkable structure allows for freedom of movement while providing a cushioned, protected conduit from mother to fetus. Fetal development and survival are dependent upon the umbilical cord. This article reviews abnormalities of the umbilical cord that can be seen with structural and chromosomal abnormalities and altered umbilical cord flow associated with fetal growth restriction and poor pregnancy outcomes.

Effect of abnormal placental cord insertion on hemodynamic change of umbilical cord in a tertiary center: a prospective cohort study

BACKGROUND

Our study aims to evaluate the umbilical vein (UV) hemodynamic change in the prenatal cohort of pregnancies diagnosed with abnormal placental cord insertion (aPCI).

METHODS

From January 2022 to December 2022, the fetal umbilical cord insertion site was sonographically examined in singleton fetuses, and umbilical cord blood flow was calculated. The umbilical artery and UV Doppler flow indexes were assessed in cases of normal and abnormal cord insertion.

RESULTS

Among 570 singleton fetuses between 18 + 0 and 40 + 6 weeks of gestation in the final study, the umbilical vein blood flow (UVBF) in the 3 groups of normal umbilical cord insertions, marginal umbilical cord insertions, and velamentous umbilical cord insertions was 145.39 ml/min, 146.18 ml/min, and 93.96 ml/min, respectively. UVBF was significantly lower in the velamentous cord insertion (VCI) group than in the other groups (P < 0.05). Compared with the normal cord insertions group, lower birth weight (2820 ± 527 g vs. 3144 ± 577 g, P < 0.05), delivery at an earlier gestational age (38.0 ± 1.55 weeks vs. 38.8 ± 2.34 weeks, P < 0.05), higher bicarbonate (25.08 ± 1.72 mmol/L vs. 22.66 ± 4.05 mmol/L, P < 0.05), and higher standard base excess (-1.14 ± 1.50 mmol/L vs. -3.30 ± 3.22 mmol/L, P < 0.05) were found in the VCI group.

CONCLUSIONS

We observed lower UVBF volume with aPCI. Hence, we propose UVBF analysis to evaluate fetal aPCI according to UV hemodynamics as an advisory in prenatal care. This would be useful and improve obstetricians' clinical explanation about the potential prenatal consequences so that parents can opt for future prenatal care during pregnancy.

Quantitative assessment system for placental gross examination with precise localization of umbilical cord insertion point

A quantitative assessment for measuring the placenta during gross examination is a crucial step in evaluating the health status of both the mother and the fetus. However, in the current clinical practice, time-consuming and observer-variant drawbacks are caused due to manual measurement and subjective determination of placental characteristics. Therefore, we propose a quantitative assessment system for placenta gross examination to efficiently and accurately measuring placental characteristics according to Amsterdam Consensus, including weight and thickness of placenta, length and width of placental disc, length and diameter of umbilical cord, distance from umbilical cord insertion point to placental edges, etc. The proposed system consists of (1) an instrument designed for standard acquisition of image, weight and thickness of placenta and (2) an algorithm for quantitative morphological assessment based on precise segmentation of placental disc and umbilical cord and localization of umbilical cord insertion point. Considering the complexity of spatial distribution and ambiguous texture of umbilical cord insertion point, we design Umbilical Cord Insertion Point Candidate Generator to provide reliable umbilical cord insertion point location by employing prior structural knowledge of umbilical cord. Therefore, we integrate the Umbilical Cord Insertion Point Candidate Generator with a Base Detector to ensure umbilical cord insertion point is provided when the Base Detector fails to generate high-scoring candidate points. Experimental results on our self-collected placenta dataset demonstrate the effectiveness of our proposed algorithm. The measurements of placental morphological assessment are calculated based on segmentation and localization results. Our proposed quantitative assessment system, along with its associated instrument and algorithm, can automatically extract numerical measurements to boost the standardization and efficiency of placental gross examination.

Risk Factors of Marginal Cord Insertion in Singleton Pregnancies: A Systematic Review and Meta-Analysis

Background: Marginal cord insertion (MCI) is increasingly recognized as a pathological variation that necessitates early diagnosis. Identifying the risk factors associated with MCI is essential for improving prenatal screening and optimizing management strategies. Our meta-analysis systematically and quantitatively synthesizes the current evidence on various potential risk factors for MCI. Methods: This systematic review and meta-analysis adhered to the PRISMA and MOOSE guidelines. Comprehensive searches were performed in three databases up until 6 May 2024, identifying observational cohort and case-control studies that examined risk factors for MCI in singleton pregnancies compared with central or eccentric cord insertion. Quality and risk of bias assessment were performed using the Newcastle-Ottawa Scale and the Quality In Prognosis Studies tool, respectively. Statistical analyses employed random-effects models to calculate relative risks (RR) and mean differences with their 95% confidence intervals (95% CI). Heterogeneity was assessed via Cochran's Q and I2 statistics. Results: A total of 18 studies (14 cohort and 4 case-control), encompassing 51,463 MCI cases and 901,020 control cases, were included. The meta-analysis revealed a prevalence of MCI at 5.71% among singleton pregnancies. Significant risk factors for MCI included the use of assisted reproductive technology (RR = 1.55; 95% CI: 1.34-1.78), chronic hypertension (RR = 1.47; 95% CI: 1.11-1.95), placenta previa (RR = 1.83; 95% CI: 1.62-2.08), and nulliparity (RR = 1.18; 95% CI: 1.08-1.30). No significant associations were found for smoking, maternal age, prior Cesarean section, preexisting diabetes, or Caucasian ethnicity. Sensitivity analyses corroborated the robustness of these findings. Conclusions: This meta-analysis identified assisted reproductive technology, chronic hypertension, placenta previa, and nulliparity as significant risk factors for marginal cord insertion in singleton pregnancies. These findings can inform the development of prenatal screening protocols and enable targeted screenings for high-risk populations.

Pathologic findings of the placenta and clinical implications - recommendations for placental examination

The placenta is a unique and complex organ that combines the circulatory systems of two or more individuals within a single dynamic organ with a set, short lifespan. A diverse spectrum of disorders, including infections as well as metabolic, genetic, circulatory, and maturation defects, may affect its function. Pathology investigation of the placenta is key for identifying several pathogenic processes in both the mother and the foetus. Aberrant placentation, maternal and foetal vascular compromise, infection, inflammatory immunologic conditions, and disorders of maturation are elements of newly proposed classification schemes. The clinical impact of placental examination consists of diagnosing maternal and foetal disease, identifying the potential for recurrence, correlating clinical pathological findings with distinct morphologic features, and identifying the aetiology responsible for growth restriction or foetal death. Gestational trophoblastic disease occurs more frequently in the first trimester; however, in very rare cases, it can affect the term or third-trimester placenta. The application of reproducible nomenclature is expected to facilitate progress in the diagnosis and treatment of obstetric and foetal disorders with placental manifestation. Therefore, this review aims to facilitate communication between obstetricians, neonatologists, and pathologists involved in this diagnostic process.

Risk Factors of Velamentous Cord Insertion in Singleton Pregnancies-A Systematic Review and Meta-Analysis

Objective: This meta-analysis aims to quantitatively summarize current data on various potential risk factors of velamentous cord insertion (VCI). A better understanding of these risk factors could enhance prenatal identification both in settings with routine screening and in those where universal screening for cord insertion anomalies is not yet recommended. Methods: A systematic search was conducted in MEDLINE, Cochrane Library, and Scopus from their inception until 7 February 2024. Eligible studies included observational studies of singleton pregnancies with VCI, identified either prenatally or postnatally, compared with pregnancies with central or eccentric cord insertion. Analyses were performed using DerSimonian and Laird random-effects models, with outcomes reported as risk ratios (RR) or mean differences with 95% confidence intervals (CI). Results: In total, 14 cohort and 4 case-control studies were included, reporting on 952,163 singleton pregnancies. Based on the cohort studies, the overall prevalence of VCI among singleton pregnancies was calculated to be 1.54%. The risk of VCI was significantly higher among pregnancies conceived using assisted reproductive technology (RR, 2.32; 95% CI: 1.77-3.05), nulliparous women (RR, 1.21; 95% CI: 1.15-1.28), women who smoked (RR, 1.14; 95% CI: 1.08-1.19), and pregnancies diagnosed with placenta previa (RR, 3.60; 95% CI: 3.04-4.28). Conclusions: This meta-analysis identified assisted reproductive technology, nulliparity, smoking, and placenta previa as significant risk factors of VCI among singleton pregnancies. These findings could inform screening policies in settings where universal screening for cord insertion is not routinely performed, suggesting a targeted approach for women with these specific risk factors.

Maternal affective symptoms and sleep quality have sex-specific associations with placental topography

BACKGROUND

The impacts of prenatal maternal affective symptoms on the placental structure are not well-established. Employing Geographic Information System (GIS) spatial autocorrelation, Moran's I, can help characterize placental thickness uniformity/variability and evaluate the impacts of maternal distress on placental topography.

METHODS

This study (N = 126) utilized cohort data on prenatal maternal affective symptoms and placental 2D and 3D morphology. Prenatal maternal depression, stress, anxiety and sleep quality were scored for each trimester using the Edinburgh Postnatal Depression Scale (EPDS), Stressful Life Event Scale (SLE), Penn State Worry Questionnaire (PSWQ), and Pittsburgh Sleep Quality Index (PSQI), respectively. Placental shape was divided into Voronoi cells and thickness variability among these cells was computed using Moran's I for 4-nearest neighbors and neighbors within a 10 cm radius. Sex-stratified Spearman correlations and linear regression were used to study associations between mean placental thickness, placental GIS variables, placental weight and the average score of each maternal variable.

RESULTS

For mothers carrying boys, poor sleep was associated with higher mean thickness (r = 0.308,p = 0.035) and lower placental thickness uniformity (r = -0.36,p = 0.012). Lower placental weight (r = 0.395,p = 0.003), higher maternal depression (r = -0.318,p = 0.019) and worry/anxiety (r = -0.362,p = 0.007) were associated with lower placental thickness uniformity for mothers carrying girls.

LIMITATIONS

The study is exploratory and not all GIS models were developed. Excluding high-risk pregnancies prevented investigating pregnancy complications related hypotheses. A larger sample size is needed for greater confidence for clinical application.

CONCLUSIONS

Placental topography can be studied using GIS theory and has shown that prenatal maternal affective symptoms and sleep have sex-specific associations with placental thickness.

A study on the correlation of placental anastomosis and superficial vascular branches of selective fetal growth restriction in monochorionic diamniotic twins

INTRODUCTION

The main purpose of the present study was to investigate the correlation between placental anastomosis and superficial vascular branches in selective fetal growth restriction (sFGR) in monochorionic diamniotic twins.

MATERIALS AND METHODS

This was a retrospective analysis of the pregnancy data and placental perfusion of 395 patients with monochorionic diamniotic (MCDA) twin pregnancies delivered at our hospital from April 2013 to April 2020. We divided the patients into two groups and compared the number of placental superficial vascular branches in sFGR twins and normal MCDA twins. The correlation between the placental anastomosis and the number of superficial vascular branches in sFGR and normal MCDA twins was also investigated.

RESULTS

The number of umbilical arterial branches and umbilical venous branches was less than larger twins in sFGR, larger twins in normal MCDA and smaller twins in normal MCDA. (11.83 [4-44], 21.82 [7-50], 19.72 [3-38], 14.85 [0-31], p < 0.001, 6.08 [1-18], 9.60 [3-22], 9.96 [2-22], 8.38 [1-20], p < 0.00) For smaller twins in the sFGR group, the number of umbilical venous branches was positively associated with AA anastomosis overall diameter, AV anastomosis overall diameter and all anastomosis overall diameter. (r = 0.194, 0.182 and 0.211, p < 0.05) CONCLUSIONS: The risk of sFGR may arise when the placenta from MCDA twins shows a poor branching condition of placental superficial vessels. For the smaller twin of sFGR, regular ultrasound examination of the number of the umbilical venous branches may help to predict artery-to-artery (AA) overall diameter, artery-to-vein (AV) overall diameter and all anastomosis overall diameter.

The Placenta: A Maternofetal Interface

The placenta is the gatekeeper between the mother and the fetus. Over the first trimester of pregnancy, the fetus is nourished by uterine gland secretions in a process known as histiotrophic nutrition. During the second trimester of pregnancy, placentation has evolved to the point at which nutrients are delivered to the placenta via maternal blood (hemotrophic nutrition). Over gestation, the placenta must adapt to these variable nutrient supplies, to alterations in maternal physiology and blood flow, and to dynamic changes in fetal growth rates. Numerous questions remain about the mechanisms used to transport nutrients to the fetus and the maternal and fetal determinants of this process. Growing data highlight the ability of the placenta to regulate this process. As new technologies and omics approaches are utilized to study this maternofetal interface, greater insight into this unique organ and its impact on fetal development and long-term health has been obtained.

Peripheral cord insertion is associated with adverse pregnancy outcome only when accompanied by clinically significant placental pathology

OBJECTIVE

To examine the relationship between umbilical cord insertion site, placental pathology and adverse pregnancy outcome in a cohort of normal and complicated pregnancies.

METHODS

Sonographic measurement of the cord insertion and detailed placental pathology were performed in 309 participants. Associations between cord insertion site, placental pathology and adverse pregnancy outcome (pre-eclampsia, preterm birth, small-for-gestational age) were examined.

RESULTS

A total of 93 (30%) participants were identified by pathological examination to have a peripheral cord insertion site. Only 41 of the 93 (44%) peripheral cords were detected by prenatal ultrasound. Peripherally inserted cords were associated significantly (P < 0.0001) with diagnostic placental pathology (most commonly with maternal vascular malperfusion (MVM)); of which 85% had an adverse pregnancy outcome. In cases of isolated peripheral cords, without placental pathology, the incidence of adverse outcome was not statistically different when compared to those with central cord insertion and no placental pathology (31% vs 18%; P = 0.3). A peripheral cord with an abnormal umbilical artery (UA) pulsatility index (PI) corresponded to an adverse outcome in 96% of cases compared to 29% when the UA-PI was normal.

CONCLUSIONS

This study demonstrates that peripheral cord insertion is often part of the spectrum of findings of MVM disease and is associated with adverse pregnancy outcome. However, adverse outcome was uncommon when there was an isolated peripheral cord insertion and no placental pathology. Therefore, additional sonographic and biochemical features of MVM should be sought when a peripheral cord is observed. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Association of placental and umbilical cord characteristics with cerebral palsy: national cohort study

OBJECTIVES

Cerebral palsy (CP) is a group of movement disorders usually diagnosed in childhood. A substantial proportion are thought to be caused by antenatal events. Abnormalities of the umbilical cord and placenta are associated with an increased risk of adverse neonatal outcomes, but it is unclear whether these conditions also carry an increased risk of CP. We aimed to determine whether abnormalities of the umbilical cord or placenta are associated with CP and assess if these associations differ by sex of the child or gestational age at birth.

METHODS

We performed a national cohort study by linking data from The Medical Birth Registry of Norway with other national registries. All liveborn singletons born between 1999 and 2017 (n = 1 087 486) were included and followed up until the end of 2019. Diagnoses of CP were provided by the Norwegian National Insurance Scheme and the Norwegian Patient Register. We used generalized estimating equations and multilevel log binomial regression to calculate relative risks (RR), adjusted for year of birth, and stratified analyses were carried out based on sex and gestational age at birth. Exposures were abnormal umbilical cord (velamentous or marginal insertion, single umbilical artery (SUA), knots and entanglement), and placental abnormalities (retained placenta, placental abruption and previa).

RESULTS

A total of 2443 cases with CP (59.8% males) were identified. Velamentous cord insertion (adjusted RR (aRR), 2.11 (95% CI, 1.65-2.60)), cord knots (aRR, 1.53 (95% CI, 1.15-2.04)) and placental abnormalities (placenta previa (aRR, 3.03 (95% CI, 2.00-4.61)), placental abruption (aRR, 10.63 (95% CI, 8.57-13.18)) and retained placenta (aRR, 1.71 (95% CI, 1.32-2.22))) carried an increased risk of CP. Velamentous cord insertion was associated with CP regardless of gestational age or sex. A retained placenta was associated with a 2-fold increased risk for CP in males, while the associations of SUA and cord knot with CP were significant only among females.

CONCLUSIONS

The detection of placental and umbilical cord abnormalities may help identify children at increased risk of CP. The associations between placental or umbilical cord abnormalities and the risk of CP do not vary substantially with gestational age at birth or sex of the child. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Impact of velamentous cord insertion on perinatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Velamentous cord insertion may be identified prenatally, but the clinical implications of this diagnosis remain controversial. This meta-analysis aimed to quantitatively summarize current data on the association of velamentous cord insertion and adverse perinatal outcomes.

DATA SOURCES

A systematic search was performed in MEDLINE, Scopus, and the Cochrane Library from inception until May 22, 2022 to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Observational studies including singleton pregnancies with velamentous cord insertion, either prenatally or postnatally identified, and comparing them with those with central/eccentric cord insertion were considered eligible.

METHODS

The quality of the studies was assessed with the Newcastle-Ottawa scale and the risk of bias with the Quality In Prognosis Studies (QUIPS) tool. The main outcome was small-for-gestational-age neonates. Heterogeneity of the studies was evaluated using a Q test and an I² index. Analyses were performed using a random-effects model, with outcome data reported as relative risk or mean difference with 95% confidence interval.

RESULTS

In total, 9 cohort and 2 case-control studies, of which 4 had prenatal and 7 had postnatal velamentous cord insertion diagnosis, were included. The overall prevalence of velamentous cord insertion was estimated to be 1.4% among singleton pregnancies. Compared with the central/eccentric cord insertion control group, pregnancies with velamentous cord insertion were at higher risk of several adverse perinatal outcomes, namely small-for-gestational-age neonates (relative risk, 1.93; 95% confidence interval, 1.54-2.41), preeclampsia (relative risk, 1.85; 95% confidence interval, 1.01-3.39), pregnancy-induced hypertension (relative risk, 1.58; 95% confidence interval, 1.46-1.70), stillbirth (relative risk, 4.12; 95% confidence interval, 1.92-8.87), placental abruption (relative risk, 2.94; 95% confidence interval, 1.72-5.03), preterm delivery (relative risk, 2.14; 95% confidence interval, 1.73-2.65), emergency cesarean delivery (relative risk, 2.03; 95% confidence interval, 1.22-3.38), 1-minute Apgar score <7 (relative risk, 1.53; 95% confidence interval, 1.14-2.05), 5-minute Apgar score <7 (relative risk, 1.97; 95% confidence interval, 1.43-2.71), and neonatal intensive care unit admission (relative risk, 1.63; 95% confidence interval, 1.32-2.02). In a subgroup analysis, prenatally diagnosed velamentous cord insertion was associated with small-for-gestational-age neonates (relative risk, 1.66; 95% confidence interval, 1.19-2.32), stillbirth (relative risk, 4.78; 95% confidence interval, 1.42-16.08), and preterm delivery (relative risk, 2.69; 95% confidence interval, 2.01-3.60). In a sensitivity analysis of studies excluding cases with vasa previa, velamentous cord insertion was associated with an increased risk of small-for-gestational-age neonates (relative risk, 2.69; 95% confidence interval, 1.73-4.17), pregnancy-induced hypertension (relative risk, 1.94; 95% confidence interval, 1.24-3.01), and stillbirth (relative risk, 9.42; 95% confidence interval, 3.19-27.76), but not preterm delivery (relative risk, 1.92; 95% confidence interval, 0.82-4.54).

CONCLUSION

Velamentous cord insertion is associated with several adverse perinatal outcomes, including stillbirth, and these associations persist when only prenatally diagnosed cases are considered and when vasa previa cases are excluded. According to these findings, the exact pathophysiology should be further investigated and an effective prenatal monitoring plan should be developed.

Anomalous Marginal Insertion of Umbilical Cord in Placentas of COVID-19-Affected Pregnant Mothers: A Cross-Sectional Study

Aim Study the effect of coronavirus disease-19 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), on the placenta and in turn study its effects on pregnancy and newborn outcomes. Methods In this cross-sectional study, which was conducted in the term pregnant women who underwent delivery, their placentas were collected after delivery along with the mothers' blood and cord blood. Results Among the 212 pregnant women recruited, the prevalence of marginal cord insertion (MCI) in the placentas after delivery, was found to be 23% (n=48). Among these 48 cases (n=48) with MCI, 58.33% (n=28) were COVID-19 positive. The placentas with MCI had significantly lower minimum placental circumference (probability value/p value=0.04) and significantly longer umbilical cord (p-value=0.05). COVID-19 antibodies transfer from the mother to the umbilical cord (C/M antibodies ratio) was observed to be lower, albeit insignificantly. Both the weight of newborns (p value=0.03) and their COVID-19 antibodies levels (p-value=0.05) were observed to be significantly lower in the MCI group. Univariate analysis shows that a body mass index (BMI) ≥ 23 of the mothers was significantly associated with abnormal MCI. Conclusion The prevalence of MCI was observed to be high in COVID-19-affected mothers in our study. MCI was associated with lower placental size, newborn weight, lesser transfer of COVID-19 antibodies from the mother to the fetus across the umbilical cord, and lower antibody levels in the cord blood when compared to maternal blood.

Allometric scaling relationships in mouse placenta

Fetal growth and maturation are highly intertwined with placental development during pregnancy. Here we used placental vascular morphology measurements (depth and span) as well as the umbilical artery (UA) diameter of previously published studies on three different mouse strains (C57BL6/J, CD-1 and BALB/c), which were exposed to different conditions (combination antiretroviral therapy, chronic maternal hypoxia and malaria infection) at different embryonic days, to test the hypothesis that placental vascularization and specifically the UA size affect conceptus weight. Interaction of each study parameter with embryonic day, strain and exposure to treatments are studied to investigate the stability of the scaling relationships across and/or within strains and conditions. In addition, the effect of UA diameter on the placental growth measurements (depth and span) is studied. These results show that the power-law scaling relationship of conceptus weight and placental depth with the UA diameter is conserved across strains and conditions with the scaling exponent of approximately 3/8 and 5/8, respectively. By contrast, the relationship between conceptus weight and either the placental span or depth is different between strains and conditions, suggesting multiple mechanisms of vascular adaptation.

Impact of Marginal and Velamentous Cord Insertion on Uterine Artery Doppler Indices, Fetal Growth, and Preeclampsia

OBJECTIVES

To assess the impact of marginal (MCI) or velamentous (VCI) cord insertion on uterine artery pulsatility index (UtA PI), preeclampsia (PE), and offspring's birthweight (BW).

METHODS

A retrospective cohort study of singleton pregnancies, undergoing routine anomaly scan at 20⁺⁰ -23⁺⁶ gestational weeks, was conducted between 2016 and 2020. The effect of placental cord insertion on BW and UtA mean PI z-scores was assessed using the t test or analysis of variance and post-hoc tests; their association with PE was evaluated with the chi-square test. A multivariate logistic regression model was employed to assess the independent association of placental cord insertion and UtA PI z-score with PE, BW <10th, <5th centile, and intrauterine death (IUD), using specific confounders.

RESULTS

The study population included 4453 pregnancies. Conception via assisted reproductive technology (ART) was associated with increased risk of abnormal cord insertion (odds ratio [OR]: 2.237; 95% confidence interval [CI]: 1.561-3.206; P < .001). Women with MCI/VCI had higher mean UtA PI z-score than those with central/eccentric (0.29 vs 0.01; mean difference: -0.28; 95% CI: -0.399 to -0.165; P < .001). MCI/VCI were associated with higher rates of BW <10th centile (central/eccentric: 16.2% vs MCI: 21.9% vs VCI: 35.7%; P < .001) and BW <5th centile (9.8 vs 15.1 vs 23.2%, respectively; P < .001). No association was identified between MCI/VCI and PE (P = .968). Finally, VCI (aOR: 13.717; 95% CI: 1.576-119.379; P = .018) and increased BMI (aOR: 1.167; 95% CI: 1.071-1.271; P < .001) significantly correlated with IUD.

CONCLUSIONS

Abnormal cord insertion is more common in ART pregnancies. MCI/VCI are associated with higher mean UtA PI and lower BW centile, but not with increased risk of PE.

Placental morphology in association with autism-related traits in the EARLI study

Background

In prior work we observed differences in morphology features in placentas from an autism-enriched cohort as compared to those from a general population sample. Here we sought to examine whether these differences associate with ASD-related outcomes in the child.

Methods

Participants (n = 101) were drawn from the Early Autism Risk Longitudinal Investigation (EARLI), a cohort following younger siblings of children with autism spectrum disorder (ASD). ASD-related outcomes, including the Social Responsiveness Scale (SRS), Mullen Scales of Early Learning (MSEL) Early Learning Composite, and ASD diagnosis, were assessed at age 3. Crude and adjusted linear regression was used to examine associations between placental morphological features (parametrized continuously and in quartiles) and SRS and MSEL scores; comparisons by ASD case status were explored as secondary analyses due to the small number of cases (n = 20).

Results

In adjusted analyses, we observed a modest positive association between umbilical cord eccentricity, defined as the ratio of the maximum:minimum radius from the cord insertion point, and SRS scores (Beta = 1.68, 95%CI = 0.45, 2.9). Positive associations were also suggested between placental maximum thickness and cord centrality and SRS scores, though these were estimated with little precision. Associations between other placental morphological features and outcomes were not observed.

Conclusions

Our analyses suggested a potential association between umbilical cord features and ASD-related traits, of interest as non-central cord insertion may reflect reduced placenta efficiency. Future studies with larger sample sizes are needed to further examine these and other placental features in association with ASD-related outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04851-4.

Maternal exposure to fine particulate matter over the first trimester and umbilical cord insertion abnormalities

BACKGROUND

Our hypothesis was that exposure to fine particulate matter (PM2.5) is related to abnormal cord insertion, which is categorized as a form of placental implantation abnormality. We investigated the association between exposure to total PM2.5 and its chemical components over the first trimester and abnormal cord insertion, which contributes to the occurrence of adverse birth outcomes.

METHODS

From the Japan Perinatal Registry Network database, we used data on 83 708 women who delivered singleton births at 39 cooperating hospitals in 23 Tokyo wards (2013-2015). We collected PM2.5 on a filter and measured daily concentrations of carbon and ion components. Then, we calculated the average concentrations over the first trimester (0-13 weeks of gestation) for each woman. A multilevel logistic-regression model with the hospital as a random effect was used to estimate the odds ratios (ORs) of abnormal cord insertion.

RESULTS

Among the 83 708 women (mean age at delivery = 33.7 years), the frequency of abnormal cord insertion was 4.5%, the median concentration [interquartile range (IQR)] of total PM2.5 was 16.1 (3.61) μg/m3 and the OR per IQR for total PM2.5 was 1.14 (95% confidence interval = 1.06-1.23). In the total PM2.5-adjusted models, total carbon, organic carbon, nitrate, ammonium and chloride were positively associated with abnormal insertion. Organic carbon was consistently, and nitrate tended to be, associated with specific types of abnormal insertion (marginal or velamentous cord insertion).

CONCLUSIONS

Exposure to total PM2.5 and some of its components over the first trimester increased the likelihood of abnormal cord insertion.

Influence of the placental cord insertion site on the placental mass and the birth weight in dichorionic diamniotic twins

The aim of the study was to determine the effect of the displacement of the umbilical cord insertion site from the centre of the placenta on the placental mass and the birth weight of dichorionic diamniotic twins and to consider the importance of the direction of the displacement, as well as to assess the influence of the umbilical cord displacement on the placental mass and the birth weight of dichorionic diamniotic twins taking into account the direction of displacement. Material and methods. The study was performed on 135 dichorionic diamniotic pairs: 68 opposite-sex, 35 same-sex males, and 32 same-sex females. The impact of an absolute cord displacement from the centroid of the placental disc and the direction of its shifting were compared with the birth weight and the placental mass. Results. In the investigated group, a central insertion was revealed in 6 (2.2 %), eccentric – in 224 (83.0 %), marginal – in 31 (11.5 %), and velamentous – in 9 (3.3 %) cases. The first two types of cord insertion are considered to be normal, the third and the fourth are seen as abnormal. The placental mass was in a strong positive correlation with the birth weight (r=0.71, p<0.0001). The placentas with an eccentric cord insertion had a smaller surface area. A negative correlation was established between the displacement of the cord insertion site and the placental mass (r=-0.4284, p<0.0001) as well as the birth weight (r=-0.6115, p<0.0001). The shift along the long axis was of greater importance than in relation to the shorter one. The placental mass and the birth weight were higher in the new-borns with a normal cord insertion site. In the abnormal cord insertion group, 32.5 % of the infants were under the 10th birth weight percentile, in the normal cord insertion group – only 8.3 %. Conclusions. The birth weight of dichorionic diamniotic twins and their placental mass are negatively correlated with the distance of the umbilical cord insertion site from the placental centre. The insertion site displacement along the long axis has a stronger negative effect on the birth weight and the placental mass in comparison with the shifting along the short axis. The placentas with an eccentric cord insertion have a smaller surface area.

Marginal cord insertion among singleton births at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

Umbilical cord may insert abnormally i.e. marginal insertion to a placenta which can cause different birth and perinatal complications. Despite the increased effort taken by different responsible bodies, the prevalence of birth and perinatal complications are still high, possibly due to anomalous cord insertion. So far, anomalous cord insertion lacks proper attention in different medical settings. Hence, the present study aims to assess the magnitude, risk factors, and adverse birth outcomes of marginal cord insertion among singleton births.

METHODS

An institution-based cross-sectional study design was conducted. A systematic random sampling technique was used to select study participants. Data were collected by using a structured questionnaire and it was entered into epi-data version 3.1 then exported to SPSS version 20 for data cleansing and analysis. Bi-variable and multivariable logistic regressions were employed to identify risk factors and adverse outcomes associated with marginal cord insertions. Crude and adjusted odds ratio (P-value < 0.05) with a 95% confidence interval were calculated.

RESULT

The magnitude of marginal cord insertion was 6.4% (95% CI = 4.4-8.8%) in singleton pregnancies. Independent risk factors for marginal cord insertion were advanced maternal age (AOR = 2.24, 95% CI: 1.35-11.08), primiparity (AOR = 1.98, 95% CI: 1.37-8.69), maternal chronic hypertension (AOR = 3.07, 95% CI: 1.66-9.76), previous cesarean delivery (AOR = 2.51, 95% CI: 1.43-10.21), and use of intrauterine contraceptive device before pregnancy (AOR = 2.22, 95% CI: 1.36-12.30). Pregnancies complicated by marginal cord insertion are at higher risk to develop low birth weight (AOR = 2.89, 95% CI: 1.23-6.80), preterm birth (AOR = 4.00, 95% CI: 1.44-11.14), and emergency cesarean delivery (AOR = 3.68, 95% CI: 1.03-13.81).

CONCLUSION AND RECOMMENDATION

Marginal cord insertion is a mistreated potential risk for low birth weight, preterm birth, and emergency cesarean delivery. Routine screening of marginal cord insertion should be considered in pregnancies with advanced age, nulliparity, hypertensive disorder, history of cesarean section, and intrauterine contraceptive device usage before pregnancy.

Exploring the impact of HIV infection and antiretroviral therapy on placenta morphology

INTRODUCTION

Women living with HIV experience more adverse birth outcomes; the mechanisms are not fully understood. We examined placenta morphology and associations with birth outcomes in a Canadian cohort of women living with HIV (HIV⁺) on antiretroviral therapy (ART) from conception and HIV-uninfected (HIV^-) women.

METHODS

Term placentas from 94 women (40 HIV^-, 54 HIV⁺) were studied. Trimmed placenta weight was collected. Placenta digital photos were used to compute morphometric parameters. Regression models investigated associations between log-transformed placenta parameters and birth outcomes.

RESULTS

We observed a trend towards lower placenta weight and smaller placenta area in the HIV⁺ group, both of which were significantly associated with small for gestational age births. HIV⁺ serostatus was associated with 6-fold (95%CI 2-20) greater odds of having placenta area in the lowest quartile (<236 cm²). Cord marginality (distance from the edge) was significantly lower in the HIV⁺ group (p = 0.004), with 35% of placenta having an abnormal (marginal or velamentous) cord insertion vs. 12.5% in the HIV^- group (p = 0.01). Velamentous cord insertion was seen in 13% of placentas in the HIV⁺ vs. 0% in HIV^- group (p = 0.02). A significant correlation between cord marginality and placenta thickness was observed in the HIV^- group, with a more marginal cord being associated with a thicker placenta. This correlation was not observed in the HIV⁺ group. HIV⁺ placentas exposed to protease inhibitors were significantly less circular compared to the HIV^- group (p = 0.03).

CONCLUSION

Our data suggest that HIV/ART exposure affects placenta morphology and is associated with higher rates of abnormal cord insertion.

Placental cord insertion distance from the placental margin and its association with adverse perinatal outcomes

OBJECTIVE

The placental cord insertion (PCI) to the placental margin has not been well studied as a continuous variable in relation to birth outcomes. We sought to evaluate the impact of PCI distance on outcomes associated with placental function and development of fetal growth restriction (FGR).

STUDY DESIGN

This was a retrospective study of singleton gestations that underwent a fetal anatomy ultrasound from 2011-2013. The PCI was recorded as the distance in centimeters from the placental margin. Patients had FGR if the overall estimated fetal weight was <10 % for gestational age or abdominal circumference <5 % in the third trimester. Delivery, obstetric, and neonatal outcomes were obtained via medical chart review. Logistic and linear regression models were used to assess the impact of PCI distance on maternal and neonatal delivery outcomes.

RESULTS

Of the 1443 women who met inclusion criteria, 93.6 % delivered at term. The mean (±SD) PCI distance was 4.4 ± 1.4 cm. There was no association between PCI and cesarean delivery, peripartum hemorrhage (PPH), pre-eclampsia, 5-min Apgar, or intrauterine fetal demise. PCI distance was statistically significantly shorter in patients requiring neonatal intensive care unit (NICU) admission (4.1 ± 1.5 cm vs. 4.4 ± 1.4 cm, p = 0.02) and was associated with lower birthweight (p = 0.01), though this association was no longer seen when corrected for gestational age. There were 3.5 % of patients who developed FGR; PCI distances from the placental edge were not significantly different for patients who developed FGR compared to those who did not (4.2 ± 1.4 cm vs. 4.5 ± 1.4 cm, p = 0.18). Furthermore, a receiver operating characteristic (ROC) curve for PCI had poor sensitivity (area under the curve [AUC] 0.57, 95 % CI 0.49-0.65).

CONCLUSION

PCI distance at the time of fetal anatomic survey is significantly associated with NICU admission, though does not appear to impact rates of preterm birth, pre-eclampsia, PPH or cesarean delivery. PCI distance in singleton gestations does not appear to be predictive of FGR.

Correlation between chorionic plate vascularization and risk of bronchopulmonary dysplasia in extremely preterm infants

INTRODUCTION/OBJECTIVES

The chorionic plate vessels of the placenta are in direct continuity with the fetal vasculature, suggesting chorionic and fetal angiogenesis may be subjected to similar regulatory mechanisms. In this study, we determined the correlation between chorionic plate vascularization and complications of prematurity, focusing on bronchopulmonary dysplasia (BPD) and other conditions with important microvascular components.

METHODS

We performed a clinicoplacental analysis of 127 extremely preterm infants (23-28 weeks gestation). Chorionic plate vascularization was assessed by number and density of perforating chorionic vessels (PCVs). Charts were reviewed for relevant maternal and neonatal data, including respiratory, neurologic and gastrointestinal complications of prematurity.

RESULTS

The placentas displayed marked variability in number (36-523/placenta) and density of PCVs (0.46-3.74 PC V/cm²). The median PCV density of infants with severe BPD was significantly higher than that of infants without BPD (1.51 PC V/cm² versus 1.09 PC V/cm², P < 0.05). Conversely, the frequency of moderate-to-severe BPD was 33% higher in infants with PCV density ≥1.50 PC V/cm² than in those with PCV density <1.50 PC V/cm² (56% versus 40%, P < 0.01). There was no correlation with neonatal neurologic or gastrointestinal complications.

CONCLUSION

Chorionic plate vascularization correlates with frequency and severity of BPD, supporting a vascular basis that in part is antenatal in origin. Quantitative assessment of chorionic plate vascularization may allow early identification of preterm infants at high risk for BPD (proposed threshold: PCV density ≥1.50 PC V/cm²). The lack of correlation between chorionic vascularization and neurologic/gastrointestinal complications suggests these conditions may have less important antenatal and/or vascular contributions.

AI-PLAX: AI-based placental assessment and examination using photos

Post-delivery analysis of the placenta is useful for evaluating health risks of both the mother and baby. In the U.S., however, only about 20% of placentas are assessed by pathology exams, and placental data is often missed in pregnancy research because of the additional time, cost, and expertise needed. A computer-based tool that can be used in any delivery setting at the time of birth to provide an immediate and comprehensive placental assessment would have the potential to not only to improve health care, but also to radically improve medical knowledge. In this paper, we tackle the problem of automatic placental assessment and examination using photos. More concretely, we first address morphological characterization, which includes the tasks of placental image segmentation, umbilical cord insertion point localization, and maternal/fetal side classification. We also tackle clinically meaningful feature analysis of placentas, which comprises detection of retained placenta (i.e., incomplete placenta), umbilical cord knot, meconium, abruption, chorioamnionitis, and hypercoiled cord, and categorization of umbilical cord insertion type. We curated a dataset consisting of approximately 1300 placenta images taken at Northwestern Memorial Hospital, with hand-labeled pixel-level segmentation map, cord insertion point and other information extracted from the associated pathology reports. We developed the AI-based Placental Assessment and Examination system (AI-PLAX), which is a novel two-stage photograph-based pipeline for fully automated analysis. In the first stage, we use three encoder-decoder convolutional neural networks with a shared encoder to address morphological characterization tasks by employing a transfer-learning training strategy. In the second stage, we employ distinct sub-models to solve different feature analysis tasks by using both the photograph and the output of the first stage. We evaluated the effectiveness of our pipeline by using the curated dataset as well as the pathology reports in the medical record. Through extensive experiments, we demonstrate our system is able to produce accurate morphological characterization and very promising performance on aforementioned feature analysis tasks, all of which may possess clinical impact and contribute to future pregnancy research. This work is the first for comprehensive, automated, computer-based placental analysis and will serve as a launchpad for potentially multiple future innovations.

Placental vascular tree characterization based on ex-vivo MRI with a potential application for placental insufficiency assessment

INTRODUCTION

Understanding regarding the whole placental vascular network structure is limited. Our aim was to quantitatively characterize the human placental vascular tree ex-vivo using high-resolution MRI.

METHODS

34 normal placentas were rinsed and injected with a solution of gelatin and contrast agent through the umbilical vessels. A sample of six placentas taken from pregnancies with intrauterine-growth-restriction (IUGR) was used to demonstrate the potential application to cases with placental insufficiency. Structural ex-vivo MR scans of the placenta were performed using high resolution T₁ weighted images. A semi-automatic method was developed to segment and characterize the placental vascular architecture: placental volume and cord insertion location; number of bifurcations, generations and vessels diameters.

RESULTS

Different vascular patterns were found in placentas with central versus marginal cord-insertion. Based on the placental volume and number of bifurcations we were able to predict birth weight. Furthermore, preliminary results on IUGR sample demonstrated the potential of this method to differentiate between small newborns with suspected IUGR from small normal newborns who reached their full growth potential. Results obtained using the automatic method were validated against manual values demonstrating no significant differences or bias. Histopathology supported the imaging findings.

DISCUSSION

This is the first study to quantitatively characterize the human placental vascular architecture using high resolution ex-vivo MRI. Different patterns of vascular architecture may be related to different functioning of the placenta and affect fetal development. This method is simple, relatively fast, provides detailed information of the placental vascular architecture, and may have important clinical applications.

Placental vascular tree characterization based on ex-vivo MRI with a potential application for placental insufficiency assessment

INTRODUCTION

Understanding regarding the whole placental vascular network structure is limited. Our aim was to quantitatively characterize the human placental vascular tree ex-vivo using high-resolution MRI.

METHODS

34 normal placentas were rinsed and injected with a solution of gelatin and contrast agent through the umbilical vessels. A sample of six placentas taken from pregnancies with intrauterine-growth-restriction (IUGR) was used to demonstrate the potential application to cases with placental insufficiency. Structural ex-vivo MR scans of the placenta were performed using high resolution T₁ weighted images. A semi-automatic method was developed to segment and characterize the placental vascular architecture: placental volume and cord insertion location, number of bifurcations, generations and vessels diameters.

RESULTS

Different vascular patterns were found in placentas with central versus marginal cord-insertion. Based on the placental volume and number of bifurcations we were able to predict birth weight. Furthermore, preliminary results on IUGR sample demonstrated the potential of this method to differentiate between small newborns with suspected IUGR from small normal newborns who reached their full growth potential. Results obtained using the automatic method were validated against manual values demonstrating no significant differences or bias. Histopathology supported the imaging findings.

DISCUSSION

This is the first study to quantitatively characterize the human placental vascular architecture using high resolution ex-vivo MRI. Different patterns of vascular architecture may be related to different functioning of the placenta and affect fetal development. This method is simple, relatively fast, provides detailed information of the placental vascular architecture, and may have important clinical applications.

Second-Trimester Ultrasound-Measured Umbilical Cord Insertion-to-Placental Edge Distance: Determining an Outcome-Based Threshold for Identifying Marginal Cord Insertions

OBJECTIVES

We sought to study potential diagnostic criteria for marginal placental cord insertions as determined by associations with obstetric outcomes.

METHODS

This single-center retrospective cohort investigation included singleton gestations delivering from January 1, 2012, to December 31, 2016, and having a standard or detailed fetal ultrasound examination from 18 weeks to 21 weeks 6 days. Cord insertion-to-placental edge distances were used to create a referent comparison group and 3 patient groups: greater than 3.0 cm (comparison); greater than 2.0 to 3.0 cm (group 1); greater than 1.0 to 2.0 cm (group 2); and 1.0 cm or less (group 3). The primary outcome consisted of any one of spontaneous delivery before 37 weeks, fetal growth restriction, oligohydramnios, placental abruption, or intrauterine fetal demise.

RESULTS

The numbers of participants and mean distances ± SDs for the comparison group and groups 1 to 3, respectively, were 628 and 4.68 ± 1.17 cm, 106 and 2.52 ± 0.26 cm, 131 and 1.60 ± 0.29 cm, and 77 and 0.36 ± 0.37 cm, respectively. The primary outcome was significantly associated only with cord insertion-to-placental edge distances of 1.0 cm or less (adjusted odds ratio, 3.05; 95% confidence interval, 1.73-5.38).

CONCLUSIONS

Marginal cord insertions may be diagnosed when the cord insertion-to-placental edge distance is 1.0 cm or less.

Placental Implantation Disorders

Primary disorders of placental implantation have immediate consequences for the outcome of a pregnancy. These disorders have been known to clinical science for more than a century, but have been relatively rare. Recent epidemiologic obstetric data have indicated that the rise in their incidence over the last 2 decades has been iatrogenic in origin. In particular, the rising numbers of pregnancies resulting from in vitro fertilization (IVF) and the increased use of caesarean section for delivery have been associated with higher frequencies of previa implantation, accreta placentation, abnormal placental shapes, and velamentous cord insertion. These disorders often occur together.

Gestational growth trajectories derived from a dynamic fetal-placental scaling law

Fetal trajectories characterizing growth rates in utero have relied primarily on goodness of fit rather than mechanistic properties exhibited in utero. Here, we use a validated fetal-placental allometric scaling law and a first principles differential equations model of placental volume growth to generate biologically meaningful fetal-placental growth curves. The growth curves form the foundation for understanding healthy versus at-risk fetal growth and for identifying the timing of key events in utero.

Assessment of the Placental Cord Insertion Using 3-Dimensional Ultrasound at the Time of the Structural Fetal Survey

OBJECTIVES

The influence of placental morphologic characteristics on pregnancy outcomes is poorly understood. Our objective was to evaluate the relationship of the distance of the placental cord insertion from the placental edge (PCI-D) with associated placental characteristics as well as birth outcomes.

METHODS

We performed a retrospective cohort study of nulliparous women with singleton gestations undergoing obstetric ultrasound examinations between 14 and 23 weeks' gestation with a cervical length of greater than 3.0 cm who delivered between 24 and 42 weeks. A 3-dimensional volume of the placenta was evaluated. The PCI-D was obtained with Virtual Organ computer-aided analysis software (GE Healthcare, Milwaukee, WI). Generalized linear regression and generalized additive models were fitted to explore the associations between the PCI-D in relation to demographic and clinical characteristics.

RESULTS

A total of 216 pregnancies were included in the analysis. The PCI-D did not correlate with maternal age, gestational age at delivery, mode of delivery, or 5-minute Apgar score. Although not statistically significant, the birth weight z score (P = .09) was associated with a longer PCI-D, and gravidity was associated with a shorter PCI-D (P = .10). A low-lying placenta or placenta previa was associated with a longer PCI-D (P = .03).

CONCLUSIONS

The PCI-D is associated with a low placental position in the second trimester. These data are helpful for understanding placental development. The PCI-D may be associated with pregnancy-related factors such as birth weight and multigravidity. More research is required to evaluate the effects of pregnancy-related factors on the PCI-D and the effect of the PCI-D on pregnancy outcomes.

Associations Between the Features of Gross Placental Morphology and Birthweight

The placenta plays a critical role in regulating fetal growth. Recent studies suggest that there may be sex-specific differences in placental development. The purpose of our study was to evaluate the associations between birthweight and placental morphology in models adjusted for covariates and to assess sex-specific differences in these associations. We analyzed data from the Stillbirth Collaborative Research Network's population-based case-control study conducted between 2006 and 2008, which recruited cases of stillbirth and population-based controls in 5 states. Our analysis was restricted to singleton live births with a placental examination (n = 1229). Characteristics of placental morphology evaluated include thickness, surface area, difference in diameters, shape, and umbilical cord insertion site. We used linear regression to model birthweight as a function of placental morphology and covariates. Surface area had the greatest association with birthweight; a reduction in surface area of 83 cm2, which reflects the interquartile range, is associated with a 260.2-g reduction in birthweight (95% confidence interval, -299.9 to -220.6), after adjustment for other features of placental morphology and covariates. Reduced placental thickness was also associated with lower birthweight. These associations did not differ between males and females. Our results suggest that reduced placental thickness and surface area are independently associated with lower birthweight and that these relationships are not related to sex.

Small for gestational age infants and the association with placental and umbilical cord morphometry: a digital imaging study

Introduction: Individual placental and umbilical cord morphometry have been previously identified to have an association with fetal growth. This study aims to identify which of the morphometric measurements in combination are associated with pregnancies with small for gestational age (SGA) infants using digital imaging of the delivered placenta.Material and methods: This study examined 1005 placentas from consecutively delivered singleton pregnancies in a tertiary center. Standardized images of each placenta were taken. Placental weight and thickness; umbilical cord length and diameter were measured on gross examination. Distance from the placental cord insertion site to placental margin, length and breadth of the placenta and placental chorionic surface area were measured digitally using ImageJ software. Logistic regression models and area under the curve (AUC) were used to identify the best subset of morphometric measurements to classify infants as SGA (<10th centile).Results: Overall, 141 (14%) infants were SGA. The morphometric measurements at delivery most strongly associated with the classification of infants as SGA were placental weight (AUC = 0.806) and placental surface area (AUC = 0.749). Of the potential antenatal morphometric measurements, umbilical cord diameters, both placental (AUC = 0.644) and fetal end (AUC = 0.629) were most strongly associated with SGA. A logistic regression model with maternal age, smoking status, current history of preeclampsia, umbilical cord length, placental weight, birthweight-to-placental weight ratio and umbilical cord diameter (placental end) had a sensitivity of 53% and a false-positive rate of 2% (AUC = 0.945) for the classification of infants as SGA.Conclusion: Placental and umbilical cord morphometry measured at delivery are different between SGA and non-SGA infants. Further studies are warranted to investigate the feasibility and accuracy of ultrasound to measure placental and umbilical cord morphometry during pregnancy.

The Possible Role of Placental Morphometry in the Detection of Fetal Growth Restriction

Fetal growth restriction (FGR) is often the result of placental insufficiency and is characterized by insufficient transplacental transport of nutrients and oxygen. The main underlying entities of placental insufficiency, the pathophysiologic mechanism, can broadly be divided into impairments in blood flow and exchange capacity over the syncytiovascular membranes of the fetal placenta villi. Fetal growth restriction is not synonymous with small for gestational age and techniques to distinguish between both are needed. Placental insufficiency has significant associations with adverse pregnancy outcomes (perinatal mortality and morbidity). Even in apparently healthy survivors, altered fetal programming may lead to long-term neurodevelopmental and metabolic effects. Although the concept of fetal growth restriction is well appreciated in contemporary obstetrics, the appropriate detection of FGR remains an issue in clinical practice. Several approaches have aimed to improve detection, e.g., uniform definition of FGR, use of Doppler ultrasound profiles and use of growth trajectories by ultrasound fetal biometry. However, the role of placental morphometry (placental dimensions/shape and weight) deserves further exploration. This review article covers the clinical relevance of placental morphometry during pregnancy and at birth to help recognize fetuses who are growth restricted. The assessment has wide intra- and interindividual variability with various consequences. Previous studies have shown that a small placental surface area and low placental weight are associated with a slower growth of the fetus. Parameters such as placental surface area, placental volume and placental weight in relation to birth weight can help to identify FGR. In the future, a model including sophisticated antenatal placental morphometry may prove to be a clinically useful method for screening or diagnosing growth restricted fetuses, in order to provide optimal monitoring.

Persistent amnion-chorion membrane separation

AIM

Fetal membranes are composed of the amnion and chorion, which fuse during the early second trimester. Persistent separation confers increased risk of adverse perinatal outcomes. This study characterizes sonographic and placental findings associated with persistent amnion-chorion (AC) membrane separation.

METHODS

This is a case series of 23 patients carrying singleton pregnancies with persistent AC membrane separation after 16 weeks' gestation diagnosed by ultrasound from 2010 to 2016 at our institution. Twenty placentas were available for analysis.

RESULTS

Obstetrical complications occurred in 13 (56.5%) cases; two (8.7%) cases resulted in intrauterine fetal demise. Fetal malformations were reported in eight (34.8%) cases. Four (17.4%) neonates were small-for-gestational age (SGA; <10th percentile). Placental size measured ≤10th percentile for gestational age in eight (40%) cases. Placental cord insertion was marginal or velamentous in eight (34.8%) cases. Maternal and/or fetal placental perfusion abnormalities occurred in 11 (55%) cases.

CONCLUSION

AC membrane separation is associated with adverse obstetrical outcomes, placental abnormalities, including marginal and velamentous cord insertion, placental growth restriction and placental perfusion defects. This membrane complication is associated with increased incidence of fetal malformations in the absence of identifiable genetic etiologies.

Placental gross shape differences in a high autism risk cohort and the general population

A growing body of evidence suggests that prenatal environment is important in Autism Spectrum Disorder (ASD) etiology. In this study, we compare placental shape features in younger siblings of children with ASD, who themselves are at high ASD risk, to a sample of low risk peers. Digital photographs of the fetal placenta surface and of the sliced placental disk from 129 high ASD risk newborns and from 267 newborns in the National Children’s Study Vanguard pilot were analysed to extract comparable measures of placental chorionic surface shape, umbilical cord displacement and disk thickness. Placental thickness measures were moderately higher in siblings of ASD cases. The placentas of ASD-case siblings were also rounder and more regular in perimeter than general population placentas. After stratification by sex, these across-group differences persisted for both sexes but were more pronounced in females. No significant differences were observed in cord insertion measures. Variations in placental shape features are generally considered to reflect flexibility in placental growth in response to changes in intrauterine environment as the placenta establishes and matures. Reduced placental shape variability observed in high ASD risk siblings compared to low-risk controls may indicate restricted ability to compensate for intrauterine changes.

Placental morphometry in hypertensive disorders of pregnancy and its relationship with birth weight in a Latin American population

OBJECTIVE

To assess the placental morphometry in pregnancies with hypertensive disorders of pregnancy (HDP) and its relationship with birth weight (BW).

STUDY DESIGN

Cohort study of placental morphometry and fetal outcomes of 954 pregnancies at a university hospital in Ribeirão Preto, São Paulo, Brazil, in 2010. HDP categories were: chronic (CH), gestational (GH), preeclampsia (PRE) and pre-eclampsia superimposed on chronic hypertension (CH + PRE). Associations between BW and placental measures (PM) in pregnancies were evaluated by multiple linear regression analyses.

MAIN OUTCOME MEASURES (PM)

Placental weight (PW, g), largest and smallest diameters (cm), thickness (cm), eccentricity, area (cm²), volume (cm³), BW/PW ratio and PW/BW ratio (efficiency).

RESULTS

The frequencies of each HDP categories were 6.5% CH; 7.6% GH; 6.1% PRE, and 2.0% CH + PRE. PW, largest and smallest diameters, area and BW/PW ratio were statistically different between HDP and the normotensive group, with the lowest values for CH + PRE; the remaining measures showed no difference. BW was lower in HDP than in the normotensive group (p = 0.016). BW and PW were highly correlated in the presence of HDP (r = 0.79, p < 0.001). Sixty-seven percent of BW variability was accounted for PM (p < 0.001), and increased to 81% when maternal variables, gestational age and sex were added (p < 0.001).

CONCLUSIONS

Hypertensive disorders of pregnancy significantly influence the growth of both the placenta and the fetus. PM explain 67% of BW variability, and CH + PRE was the category with the strongest association to the results.

Parental ethnicity and placental maternal vascular malperfusion pathology in healthy nulliparous women

INTRODUCTION

Rates of some placental-associated pregnancy complications vary by ethnicity, though the strength of association with underlying placental pathology is presently unknown. Our objective was to determine whether an association between ethnicity and placental pathology occurs in low-risk pregnancies.

METHODS

829 low-risk nulliparous pregnant women were prospectively studied. Data were obtained from standardized obstetrical appointments (clinical history, serum biomarkers, placental ultrasound) and hospital delivery records (pregnancy complications, delivery details and perinatal outcomes). Placental pathology was performed in all subjects using standard criteria.

RESULTS

In our cohort, 72% of women were Caucasian, 14% East Asian, 8% South Asian, 4% Afro-Caribbean and 3% Hispanic women. 81% of couples were concordant (same ethnic background) and 19% discordant (mixed ethnicities). South Asian women had the highest rate of small for gestational age (SGA) birth (customized birthweight <10th percentile) (24.2%), which was associated with the placental features of uteroplacental vascular insufficiency (placental weight <10th percentile with decidual vasculopathy, focal infarction, and/or syncytial knot formation) (p = 0.05). Placental efficiency varied significantly by ethnicity; Caucasian women had the highest efficiency (7.1 ± 1.2) and Afro-Caribbean women the lowest (6.5 ± 0.9) (p < 0.003). Afro-Caribbean women had the highest rate of marginal cord insertion. Placental efficiency, was higher in concordant vs. discordant couples (7.0 ± 1.2 vs. 6.8 ± 1.1; p < 0.05). Placental histopathology was not affected by parental ethnic discordance.

DISCUSSION

Maternal ethnicity influences placental efficiency and relationship between uteroplacental vascular insufficiency and SGA birth, but was not associated with other placental pathologies. Discordant parental ethnicity did not affect the development of placental pathologies or adverse pregnancy outcomes.

Development of the Human Placenta and Fetal Heart: Synergic or Independent?

The placenta is the largest fetal organ, and toward the end of pregnancy the umbilical circulation receives at least 40% of the biventricular cardiac output. It is not surprising, therefore, that there are likely to be close haemodynamic links between the development of the placenta and the fetal heart. Development of the placenta is precocious, and in advance of that of the fetus. The placenta undergoes considerable remodeling at the end of the first trimester of pregnancy, and its vasculature is capable of adapting to environmental conditions and to variations in the blood supply received from the mother. There are two components to the placental membranes to consider, the secondary yolk sac and the chorioallantoic placenta. The yolk sac is the first of the extraembryonic membranes to be vascularized, and condensations in the mesenchyme at ~17 days post-conception (p.c.) give rise to endothelial and erythroid precursors. A network of blood vessels is established ~24 days p.c., with the vitelline vein draining through the region of the developing liver into the sinus venosus. Gestational sacs of early pregnancy failures often display aberrant development of the yolk sac, which is likely to be secondary to abnormal fetal development. Vasculogenesis occurs in the villous mesenchyme of the chorioallantoic placenta at a similarly early stage. Nucleated erythrocytes occupy the lumens of the placental capillaries and end-diastolic flow is absent in the umbilical arterial circulation throughout most of the first trimester, indicating a high resistance to blood flow. Resistance begins to fall in the umbilico-placental circulation around 12–14 weeks. During normal early pregnancy the placental capillary network is plastic, and considerable remodeling occurs in response to the local oxygen concentration, and in particular to oxidative stress. In pregnancies complicated by preeclampsia and/or fetal growth restriction, utero-placental malperfusion induces smooth muscle cells surrounding the placental arteries to dedifferentiate and adopt a proliferative phenotype. This change is associated with increased umbilical resistance measured by Doppler ultrasound, and is likely to exert a major effect on the developing heart through the afterload. Thus, both the umbilical and maternal placental circulations may impact on development of the heart.

Household air pollution and chronic hypoxia in the placenta of pregnant Nigerian women: A randomized controlled ethanol Cookstove intervention

BACKGROUND

Household air pollution (HAP) is associated with adverse pregnancy outcomes.

OBJECTIVES

Investigate impact of in-utero HAP exposure on placental development and chronic hypoxia.

METHODS

Markers of chronic placental hypoxia [Hofbauer cells (HBC), syncytial knots (SK), chorionic vascular density (cVD) and hypoxia-inducible factor (HIF)] were stained by hematoxylin-eosin and/or immunohistochemically in placenta samples collected from firewood-/kerosene-users (A,n=16), and ethanol-users (B,n=20) that participated in a randomized controlled intervention trial in Ibadan, Nigeria. A third group of non-smoking and presumed natural gas-using Chicago women (C,n=12) were included in this exploratory pilot to assess for possible differences in placenta histology between similar racial groups. All patients had uncomplicated pregnancies and delivered at term.

RESULTS

HBC, SK and cVD were significantly increased among firewood-/kerosene-users compared to ethanol-users and natural gas-using Chicago women (HBC medians 5.5, 3.5, and 2.0, respectively; SK means 55.6, 41.8 and 30.1; cVD means 8.8, 6.2, and 5.2; all p<0.01). HIF expression was significantly higher in Group A compared to B and C (all p<0.001).

CONCLUSIONS

In-utero exposure to HAP is associated with pathologic changes and HIF expression consistent with chronic hypoxia in placenta of firewood/kerosene-users compared to ethanol-users with less HAP exposure and Chicago women with no presumed HAP exposure. Presence of chronic hypoxic signature in placenta of women exposed to HAP has implications for adverse pregnancy complications and future growth and development of the young children. Future larger studies need to focus on HAP exposure and placental disorders like preeclampsia and long-term health impact of in-utero exposure to HAP.

Second trimester marginal cord insertion is associated with adverse perinatal outcomes

Objectives: To determine the feasibility in visualizing placental cord insertion (PCI) during second-trimester fetal anatomical survey and the association between marginal cord insertion (MCI) and preterm delivery (PTD) and low birth weight (LBW). Our secondary objectives were to evaluate the association of MCI with adverse composite obstetrical and neonatal outcomes. Methods: A prospective cohort study was performed over a 28-month period. Women with singleton pregnancies presenting for routine anatomical survey between 18 and 22 weeks' gestation were included. PCI site was visualized on 2D grayscale and color Doppler and the shortest distance from the sagittal and transverse planes to the placental edge were recorded. MCI was diagnosed when any of measured distances was ≤2 cm. Correlations were assessed via bivariate chi-squared, independent t-test analyses and Fisher's exact tests. Regression models evaluated associations between MCI and adverse composite outcomes. Results: Three hundred one women were included and PCI was feasible in all cases. The incidence of MCI was 11.3% (n = 34). Baseline characteristics between those with and without MCI were similar, except for story of prior PTD, which was greater among those with MCI (17.65 versus 7.17%, p = .04). MCI was associated with increased likelihood of LBW (RR four; 95%CI, 1.46-10.99) and PTD (RR 3.2; 95%CI, 1.53-6.68); in multivariate analysis, we found associations between MCI and composite adverse obstetrical (RR 2.33; 95%CI, 1.30-4.19) and neonatal (RR 2.46; 95%CI, 1.26-4.81) outcomes. Conclusions: Evaluation of PCI is feasible in all cases. Second-trimester MCI is associated with increased likelihood for LBW, PTD, and composite adverse obstetrical and neonatal outcomes.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.

Eccentric placentae have reduced surface area and are associated with lower birth weight in babies small for gestational age

Placental structure and function determine birth outcomes. Placental mass does not always correlate with fetal birth weight (BW) in uncomplicated pregnancies which raises the possibility of other variables such as placental shape and cord insertion being the determinants of placental efficiency. In total, 160 women with singleton pregnancy, recruited into a pregnancy cohort were studied. Placental weight (PW) was measured and other data were obtained from clinical records. Birth outcomes were classified as small for gestational age (SGA) and appropriate for gestational age (AGA) based on fetal gender, gestational age (GA) and BW. High-resolution images of the chorionic plate were recorded. The shape of the placenta and the insertion of the cord were measured using eccentricity index (EI) and cord centrality index (CCI). Only placentae with eccentrically inserted cords (n=136) were included. The mean BW and PW were 2942 (±435) g and 414 (±82) g with average GA of 38.6 weeks. The mean CCI and EI was 0.483 (±0.17) and 0.482 (±0.16). Neither of these correlated with placental efficiency. However, EI showed negative correlation with placental surface area and breadth. Upon sub-grouping the cohort into SGA (n=32) and AGA (n=104), the SGA babies with the highest EI (third tertile) had significantly lower BW than those with the least eccentric placentae (first tertile). Although eccentric-shaped placentae were present in both SGA and AGA groups, the effect on BW was observed only in the SGA group.

Abnormal placental cord insertion and adverse pregnancy outcomes: a systematic review and meta-analysis

BACKGROUND

Abnormal placental cord insertion (PCI) includes marginal cord insertion (MCI) and velamentous cord insertion (VCI). VCI has been shown to be associated with adverse pregnancy outcomes. This systematic review and meta-analysis aims to determine the association of abnormal PCI and adverse pregnancy outcomes.

METHODS

Embase, Medline, CINAHL, Scopus, Web of Science, ClinicalTrials.gov, and Cochrane Databases were searched in December 2016 (from inception to December 2016). The reference lists of eligible studies were scrutinized to identify further studies. Potentially eligible studies were reviewed by two authors independently using the following inclusion criteria: singleton pregnancies, velamentous cord insertion, marginal cord insertion, and pregnancy outcomes. Case reports and series were excluded. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Outcomes for meta-analysis were dichotomous and results are presented as summary risk ratios with 95% confidence intervals.

RESULTS

Seventeen studies were included in the systematic review, all of which were assessed as good quality. Normal PCI and MCI were grouped together as non-VCI and compared with VCI in seven studies. Four studies compared MCI, VCI, and normal PCI separately. Two other studies compared MCI with normal PCI, and VCI was excluded from their analysis. Studies in this systematic review reported an association between abnormal PCI, defined differently across studies, with preterm birth, small for gestational age (SGA), low birthweight (< 2500 g), emergency cesarean delivery, and intrauterine fetal death. Four cohort studies comparing MCI, VCI, and normal PCI separately were included in a meta-analysis resulting in a statistically significant increased risk of emergency cesarean delivery for VCI (pooled RR 2.86, 95% CI 1.56-5.22, P = 0.0006) and abnormal PCI (pooled RR 1.77, 95% CI 1.33-2.36, P < 0.0001) compared to normal PCI.

CONCLUSIONS

The available evidence suggests an association between abnormal PCI and emergency cesarean delivery. However, the number of studies with comparable definitions of abnormal PCI was small, limiting the analysis of other adverse pregnancy outcomes, and further research is required.

Autism risk classification using placental chorionic surface vascular network features

Background

Autism Spectrum Disorder (ASD) is one of the fastest-growing developmental disorders in the United States. It was hypothesized that variations in the placental chorionic surface vascular network (PCSVN) structure may reflect both the overall effects of genetic and environmentally regulated variations in branching morphogenesis within the conceptus and the fetus’ vital organs. This paper provides sound evidences to support the study of ASD risks with PCSVN through a combination of feature-selection and classification algorithms.

Methods

Twenty eight arterial and 8 shape-based PCSVN attributes from a high-risk ASD cohort of 89 placentas and a population-based cohort of 201 placentas were examined for ranked relevance using a modified version of the random forest algorithm, called the Boruta method. Principal component analysis (PCA) was applied to isolate principal effects of arterial growth on the fetal surface of the placenta. Linear discriminant analysis (LDA) with a 10-fold cross validation was performed to establish error statistics.

Results

The Boruta method selected 15 arterial attributes as relevant, implying the difference in high and low ASD risk can be explained by the arterial features alone. The five principal features obtained through PCA, which accounted for about 88% of the data variability, indicated that PCSVNs associated with placentas of high-risk ASD pregnancies generally had fewer branch points, thicker and less tortuous arteries, better extension to the surface boundary, and smaller branch angles than their population-based counterparts.

Conclusion

We developed a set of methods to explain major PCSVN differences between placentas associated with high risk ASD pregnancies and those selected from the general population. The research paradigm presented can be generalized to study connections between PCSVN features and other maternal and fetal outcomes such as gestational diabetes and hypertension.

Maternal Vascular Malperfusion and Adverse Perinatal Outcomes in Low-Risk Nulliparous Women

OBJECTIVE

To evaluate the disease burden of placental maternal vascular malperfusion pathology in a low-risk nulliparous population and test the hypothesis that a multiparameter model in the second trimester can predict maternal vascular malperfusion with high precision.

METHODS

A single-center, prospective cohort study was conducted in healthy nulliparous women. Maternal vascular malperfusion disease burden was estimated by incidence, relative risk (RR), and population-attributable risk percent. Maternal risk factors, serum biomarkers, Doppler, and placental morphologic ultrasonography were examined in isolation and in combination for prediction of this placental pathology.

RESULTS

The incidence of maternal vascular malperfusion pathology was 8.4% (72/856). Women with pathology had higher risk of preeclampsia (8.33% compared with 1.79%; RR 4.67, 95% CI 1.85-11.77%; population-attributable risk 23.6%, 95% CI 16.9-31.6%), small for gestational age (SGA) (47.22% compared with 9.45%; RR 5.00, 95% CI 3.6-6.93%; population-attributable risk 25.2%, 95% CI 22.1-28.5%), and the composite of adverse outcomes (defined as SGA or preeclampsia) (47.22% compared with 10.59%; RR 4.46, 95% CI 3.25-6.13; population-attributable risk 22.5%, 95% CI 19.8-25.5%). The combination of parameters was superior to individual modalities alone in predicting maternal vascular malperfusion, but achieved only moderate precision (area under the curve 0.77, 95% CI 0.71-0.84).

CONCLUSION

One in 12 healthy nulliparous women develop maternal vascular malperfusion placental pathology, and these pregnancies had a 4.5 times higher risk of developing preeclampsia or delivering a SGA neonate compared with those without this pathology. A multiparameter model achieved modest precision to predict placental maternal vascular malperfusion. Importantly, in low-risk pregnancies, maternal vascular malperfusion accounts for one fourth of pregnancy outcomes with SGA or preeclampsia. The low population-attributable risk of this placental pathology for SGA and preeclampsia illustrates the importance of discovering novel associations to reduce the disease burden of these pregnancy complications.

Chorionic vascular "fit" in the human placenta: Relationship to fetoplacental outcomes

BACKGROUND

Novel measures of the chorionic plate and vessels are used to test the hypothesis that variation in placental structure is correlated with reduced birth weight (BW) independent of placental weight (PW), suggesting functionally compromised placentas.

METHODS

916 mothers recruited to the Pregnancy, Infection and Nutrition Study delivering singleton live born infants at >30 gestational weeks had placentas collected, digitally photographed and weighed prior to formalin fixation. The fetal-placental weight ratio (FPR) was calculated as birthweight/placental weight. Beta (beta) was calculated as ln(PW)/ln(BW). Chorionic disk perimeter was traced and chorionic surface shape (CS) area was calculated. "Fit" was defined as the ratio of the area of the vascular to the full chorionic surface area. The sites at which chorionic vessels dived beneath the chorionic surface were marked to calculate the chorionic surface vessel (CV) area. The centroids of shapes, the distance between centroids and other measures of shape irregularities were calculated. Principal components analysis (PCA) created three independent factors. Factors were used in regression analyses to explore relations to birth weight, trimmed placental weight, FPR, and beta. Specific measures of shape irregularity were also examined in regression analyses for interrelationships and to predict birth weight, placental weight, FPR, and beta.

RESULTS

Variables related to disk size (CS area, perimeter) were correlated with BW, GA, trimmed PW and beta. "Fit" (the ratio of CV area to CS area), measures of shape irregularities, and the distance between the cord insertion and the centroids of surface and vascular areas were also correlated with one or more of the clinical outcome variables. PCA yielded three factors that had independent effects on birth weight, placental weight, the fetal-placental weight ratio, and beta (each p < 0.0001). Addition of GA did not alter the factors' associations with outcomes. Chorionic "fit" (ratio of areas), also included within the factor analysis, was a positive predictor of birth weight (p = 0.005) and FPR (p = 0.002) and a negative predictor of beta (p = 0.01). Fit was statistically significantly associated with greater distances between the umbilical cord insertion site and the CS (p < 0.001) and CV centroids (p < 0.001), and to lesser displacement between CS and CV centroids (p < 0.001).

CONCLUSIONS

Measures of CS and CV account for variation in placental efficiency defined by beta, independent of GA. Macroscopic placenta measurements can identify suboptimal placental development.

Feeding Your Baby In Utero: How the Uteroplacental Circulation Impacts Pregnancy

The utero-placental circulation links the maternal and fetal circulations during pregnancy, ensuring adequate gas and nutrient exchange, and consequently fetal growth. However, our understanding of this circulatory system remains incomplete. Here, we discuss how the utero-placental circulation is established, how it changes dynamically during pregnancy, and how this may impact on pregnancy success, highlighting how we may address knowledge gaps through advances in imaging and computational modeling approaches.