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.

Relationship between intercellular adhesion molecule-1 and morbidly adherent placenta.

Objective Morbidly adherent placenta (MAP) is a clinical condition the prevalance of which is steadily increasing. It is described as the invasion of the placenta into the uterine wall through the myometrium and beyond. Several studies have shown that intercellular adhesion molecule-1 (ICAM-1) increases the invasion capability of tumor cells and placental cells. In our study, we investigated the expression of ICAM-1 in MAP cases. Methods This is a prospective case-control study. Eighty-nine patients who were diagnosed with MAP and 96 patients, without adherent placenta, as a control group were included in the study. ICAM-1 staining was examined by immuno-histochemical staining in placental samples. Results Of the 89 patients in the MAP group, 72 (80.8%) showed positive staining, while 26 (27%) did so in the control group. ICAM-1 positive staining in the MAP group was statistically significantly higher (P=0.03). Conclusion This is the first study investigating the relationship between MAP and ICAM-1 in the literature. In our study, we showed that ICAM-1 expression increased in the MAP group.

A multiscale model of placental oxygen exchange: The effect of villous tree structure on exchange efficiency.

The placenta is critical to fetal health during pregnancy as it supplies oxygen and nutrients to maintain life. It has a complex structure, and alterations to this structure across spatial scales are associated with several pregnancy complications, including intrauterine growth restriction (IUGR). The relationship between placental structure and its efficiency as an oxygen exchanger is not well understood in normal or pathological pregnancies. Here we present a computational framework that predicts oxygen transport in the placenta which accounts for blood and oxygen transport in the space around a placental functional unit (the villous tree). The model includes the well-defined branching structure of the largest villous tree branches, as well as a smoothed representation of the small terminal villi that comprise the placenta's gas exchange interfaces. The model demonstrates that oxygen exchange is sensitive to villous tree geometry, including the villous branch length and volume, which are seen to change in IUGR. This is because, to be an efficient exchanger, the architecture of the villous tree must provide a balance between maximising the surface area available for exchange, and the opposing condition of allowing sufficient maternal blood flow to penetrate into the space surrounding the tree. The model also predicts an optimum oxygen exchange when the branch angle is 24 °, as villous branches and TBs are spread out sufficiently to channel maternal blood flow deep into the placental tissue for oxygen exchange without being shunted directly into the DVs. Without concurrent change in the branch length and angles, the model predicts that the number of branching generations has a small influence on oxygen exchange. The modelling framework is presented in 2D for simplicity but is extendible to 3D or to incorporate the high-resolution imaging data that is currently evolving to better quantify placental structure.

PFAS alters placental arterial vasculature in term human placentae: A prospective pregnancy cohort study.

INTRODUCTION: Perfluoroalkyl substances (PFAS) are synthetic chemicals used in industrial and consumer goods that are widely detected in human populations and are associated with adverse health outcomes, including perinatal health risks and child health. One mechanism of influence may be the impact of PFAS exposure on placental structure and function. OBJECTIVES: The objective of this study is to investigate the relationship between maternal prenatal exposure to PFAS and measures of placental vascularization, and to assess whether changes in vascularization play a role in mediating the impact of PFAS on birth outcomes. METHODS: Using data from a prospective cohort study, we examined associations between second trimester PFAS (individually and as mixtures using Bayesian kernel machine regression) and placental arterial vasculature in term placentae (N = 158); secondarily we evaluated the degree to which alterations in placental arterial vasculature explained associations between PFAS exposure and birth outcomes. Placental arterial vasculature features were collected from arterial tracings of each placental image. RESULTS: In both linear regression and mixture models, natural log-transformed perfluorooctanoic acid concentrations were negatively associated with surface vasculature, indexed by the mean distance from arterial end point to perimeter (ß = -0.23, 95% CI: -0.41, -0.041); additionally, maximum arterial tortuosity was negatively associated with placental weight (ß = -0.19, 95% CI: -0.34, -0.051). There were no reliable differences in effect by fetal sex. DISCUSSION: The findings provide some of the first evidence of PFAS exposure shaping a key measure of placental vascular function, which may underlie the impact of PFAS on perinatal and child health risks.

The human placenta project: Funded studies, imaging technologies, and future directions.

The placenta plays a critical role in fetal development. It serves as a multi-functional organ that protects and nurtures the fetus during pregnancy. However, despite its importance, the intricacies of placental structure and function in normal and diseased states have remained largely unexplored. Thus, in 2014, the National Institute of Child Health and Human Development launched the Human Placenta Project (HPP). As of May 2023, the HPP has awarded over $101 million in research funds, resulting in 41 funded studies and 459 publications. We conducted a comprehensive review of these studies and publications to identify areas of funded research, advances in those areas, limitations of current research, and continued areas of need. This paper will specifically review the funded studies by the HPP, followed by an in-depth discussion on advances and gaps within placental-focused imaging. We highlight the progress within magnetic reasonance imaging and ultrasound, including development of tools for the assessment of placental function and structure.

Structural changes, increased hypoxia, and oxidative DNA damage in placenta due to maternal smokeless tobacco use.

BACKGROUND: Smokeless tobacco (SLT) consumption during pregnancy is a well-recognized health risk that causes placental damage including hypoxia and oxidative damage. Although consumption of SLT by women varies from region to region, majority of tea leave pluckers consume SLT for relieving stress and pain. Still, the effects of SLT consumption have not been evaluated in tea garden workers (TGW). While previous studies have attempted to report effects of cigarette smoke using in vitro model, hypoxia-inducible factor (HIF)-1α expression in human placentae from pregnant women exposed to SLT has not been previously studied. This study was aimed to explore the effects of SLT consumption on placental structure, expression of HIF-1α and oxidative DNA damage in sample population of TGW. METHODS: A total of 51 placentae were collected from SLT users and nonusers (n = 30 and 21, respectively) with full-term normal delivery, who were involved in the plucking of tea leaves during pregnancy in tea plantation. Low birth weight (LBW, i.e., weight <2,500 g) and normal birth weight (NBW) groups among both SLT user and nonuser were compared for the stated parameters. Placental tissues were processed for transmission electron microscopy (TEM) study and immunohistochemical analysis for the expression of HIF-1α and 8-hydroxy-2'-deoxyguanosine (8-OHdG). RESULTS: Altered ultrastructural characteristics were observed in the tertiary villi of LBW group among SLT users which included endothelial cells protrusion into capillary lumen, degenerated nuclei, significant thickening of trophoblast basement membrane and vasculo-syncytial membrane, abnormalities of the microvilli, swollen or damaged mitochondria, and dilatation in endoplasmic reticulum cisternae. Furthermore, significant reduction in the perimeter, area, and number of the stromal capillary of the tertiary villi of placenta were found in LBW group as compared with NBW group from the SLT users. Enhanced expression for HIF-1α and oxidative DNA damage (8-OHdG) biomarker was observed in SLT users as compared with nonusers. CONCLUSIONS: Maternal SLT exposure during pregnancy may be associated with villus hypoxia and consequently oxidative DNA damage. It is presumed that deleterious effect of SLT exposure on placenta could result in impairment of placental barrier, and restrict nutrient and oxygen supply from mother to fetus, and thus could be a cause of fetal growth restriction.

The effect of ergot alkaloid exposure during gestation on the microscopic morphology and vasculature of the ovine placenta.

Ergot alkaloids, a class of mycotoxins associated with ergotism, act as agonists on serotonin (5HT) receptors, specifically 5HT2a, which mediate smooth muscle contraction and vasoconstriction. The objective of this study was to examine the impact of ergot alkaloid exposure during mid and late gestation on microscopic placental structure and vascular development. Ewes were fed endophyte-infected tall fescue seed containing ergot alkaloids (E+/E+, 1.77 mg ewe-1 d-1) or endophyte-free tall fescue seed (E-/E-, 0 mg ergot alkaloids) during both mid (d 35 to d 85) and late gestation (d 86 to d 133). On d 133 of gestation, a terminal surgery was performed and two placentomes of the type B morphology were collected for microscopic analyses. Amorphous connective tissue regions were larger (p < 0.0001) and more numerous (p = 0.025) in the placentome of ergot alkaloid exposed ewes. Staining showed no difference (p = 0.83) in the number of vessels present, but luminal area of maternal vasculature was 117% greater (p < 0.0001) in ergot alkaloid exposed ewes. Results showed that exposure to ergot alkaloids during gestation slowed maturation of the fetal villi as indicated by greater amorphous connective tissue regions, and altered size and shape of blood vessels to counteract reductions in blood flow caused by vasoconstriction.