The Placental Bed

Feto-placental Unit: From Development to Function

The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.

Spectral Doppler ultrasound in the placental development of Mangalarga Marchador mares

The aim of the study was to correlate the spectral index of the right and left uterine arteries with equine placental development in mares with advanced pregnancies. We examined 32 multiparous Mangalarga Marchador mares with gestation of 150-240 days. During pregnancy, the pulsatility index (PI) and resistance index (RI) of the uterine arteries were obtained using spectral Doppler ultrasonography, and the combined uteroplacental thickness was obtained monthly using B-mode ultrasonography. The combined uteroplacental thickness correlated with gestational time of up to 13 years of age, and the significant difference was observed from the sixth month onwards. The CUPT stayed within the ideal measurements for this breed and for this gestational period. There was no correlation of CUPT with PI, however a negative and significant correlation of the RI was observed. The resistance index differed significantly among age groups, and the RI of the left uterine artery tended to decrease in all age groups. Furthermore, only RI differed significantly between the medians of gestatinal age. The left PI dropped in older mares. Thus, there an increased blood perfusion in the uterine arteries of mares with advanced pregnancies and among different age categories during placental and fetal physiological development.

Development of the human placenta

The placenta is essential for normal in utero development in mammals. In humans, defective placental formation underpins common pregnancy disorders such as pre-eclampsia and fetal growth restriction. The great variation in placental types across mammals means that animal models have been of limited use in understanding human placental development. However, new tools for studying human placental development, including 3D organoids, stem cell culture systems and single cell RNA sequencing, have brought new insights into this field. Here, we review the morphological, molecular and functional aspects of human placental formation, with a focus on the defining cell of the placenta - the trophoblast.

Impaired placental perfusion and major fetal cardiac defects

OBJECTIVE

To investigate the relationship between fetal congenital heart defects (CHD) and placental perfusion assessed by uterine artery pulsatility index (UtA-PI), in relation to development of pre-eclampsia (PE).

METHODS

This was a prospective screening study of singleton pregnancies at 19-24 weeks' gestation. Transvaginal ultrasound was used to measure UtA-PI and the values were converted into multiples of the normal median (MoM). Median MoM values in pregnancies with a fetus with isolated major CHD were compared to those without CHD, in relation to development of PE.

RESULTS

The 91 407 singleton pregnancies fulfilling the entry criteria included 206 (0.23%) with isolated major fetal CHD and 91 201 without CHD. The prevalence of PE was 4.4% in pregnancies with fetal CHD and 2.7% in those without CHD (relative risk (RR), 1.6 (95% CI, 0.84-3.04); P = 0.150); the respective values for preterm PE with delivery at < 37 weeks' gestation were 2.4% and 0.7% (RR, 3.4 (95% CI, 1.42-8.09); P = 0.006). In the total population, median UtA-PI MoM was significantly higher in those that developed PE compared to those without PE (1.22 (interquartile range (IQR), 0.94-1.57) vs 1.00 (IQR, 0.84-1.19); P < 0.0001) and, in the PE group, the median UtA-PI MoM was inversely related to gestational age at delivery (r = -0.458; P < 0.0001). The same pattern of inverse relationship between UtA-PI MoM and gestational age at delivery with PE was observed in pregnancies with and those without CHD, but, in the CHD group, compared to those without CHD, UtA-PI was significantly higher both in pregnancies with and in those without PE.

CONCLUSIONS

In pregnancies both with and without fetal CHD that develop PE, impedance to flow in the UtAs is increased and this increase is particularly marked in those with preterm PE. The prevalence of preterm PE is more than three times higher in pregnancies with than those without fetal major CHD, and the prevalence of major CHD in pregnancies with preterm PE is also more than three times higher than in those without PE. However, > 97% of pregnancies with fetal CHD do not develop preterm PE and > 99% of pregnancies with preterm PE are not associated with fetal CHD. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Screening for pre-eclampsia in the first trimester: role of maternal hemodynamics and bioimpedance in non-obese patients

OBJECTIVE

To test if maternal hemodynamics and bioimpedance, assessed at the time of combined screening for PE, are able to identify in the first trimester of gestation normotensive non-obese patients at risk for pre-eclampsia (PE) and/or intrauterine growth restriction (IUGR).

METHODS

One hundred and fifty healthy nulliparous non-obese women (body mass index < 30 kg/m² ) in the first trimester of pregnancy underwent assessment by UltraSonic Cardiac Output Monitor (USCOM) to detect hemodynamic parameters, bioimpedance analysis to characterize body composition, and combined screening for PE (assessment of maternal history, biophysical and maternal biochemical markers). Patients were followed until term, noting the appearance of PE and/or IUGR.

RESULTS

One hundred and thirty-eight patients had an uneventful pregnancy (controls), while 12 (8%) developed complications (cases). USCOM showed, in cases compared with controls, lower cardiac output (5.6 ± 0.3 vs 6.7 ± 1.1 L/min, P < 0.001), lower inotropy index (1.54 ± 0.38 vs 1.91 ± 0.32 W/m² , P < 0.001) and higher total vascular resistance (1279.8 ± 166.4 vs 1061.4 ± 179.5 dynes × s/cm⁵ , P < 0.001). Bioimpedance analysis showed, in cases compared with controls, lower total body water (53.7 ± 3.3% vs 57.2 ± 5.6%, P = 0.037). Combined screening was positive for PE in 8% of the controls and in 50% of the cases (P < 0.001). After identification of cut-off values for USCOM and bioimpedance parameters, forward multivariate logistic regression analysis identified as independent predictors of complications in pregnancy the inotropy index (derived by USCOM), fat mass (derived from bioimpedance analysis) and combined screening.

CONCLUSIONS

Combined screening for PE and assessment of bioimpedance and maternal hemodynamics can be used to identify early markers of impaired cardiovascular adaptation and body composition that may lead to complications in the third trimester of pregnancy. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiovascular function at 35-37 weeks' gestation: relation to maternal characteristics

OBJECTIVE

To examine the possible effects of maternal characteristics and obstetric and medical history on maternal cardiovascular parameters at 35-37 weeks' gestation.

METHODS

In 3013 singleton pregnancies at 35-37 weeks, maternal characteristics and medical history were recorded; uterine artery pulsatility index, mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable regression analysis was used to determine significant predictors of the cardiovascular parameters among gestational age (GA), maternal characteristics and medical history.

RESULTS

Multivariable regression analysis demonstrated that significant independent prediction of log₁₀ cardiac output and log₁₀ cardiac power was provided by GA, maternal age, weight, weight gain from the first trimester, height, racial origin, smoking, assisted conception and previous neonatal birth-weight Z-score in parous women. For log₁₀ total peripheral resistance, significant prediction was provided by GA, maternal age, height, racial origin, chronic hypertension, diabetes mellitus, assisted conception, previous neonatal birth-weight Z-score and prior pre-eclampsia (PE) in parous women. For log₁₀ stroke volume, significant prediction was provided by maternal age, height, racial origin, smoking, chronic hypertension and diabetes mellitus. For heart rate, significant prediction was provided by GA, weight, weight gain, height, racial origin, chronic hypertension, previous neonatal birth-weight Z-score and prior PE in parous women. For log₁₀ MAP, significant prediction was provided by maternal weight, racial origin, family history of PE, chronic hypertension and diabetes mellitus. For log₁₀ thoracic fluid capacity, significant prediction was provided by GA, maternal age, weight, height, racial origin and systemic lupus erythematosus or antiphospholipid syndrome. For log₁₀ ventricular ejection time, significant prediction was provided by GA, weight, height and racial origin.

CONCLUSION

Maternal cardiovascular parameters are affected by maternal characteristics and medical and obstetric history, and they should therefore be converted into multiples of the normal median adjusted for significant independent predictors before their inclusion in combined screening for PE. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac function at 35-37 weeks' gestation: prediction of pre-eclampsia and gestational hypertension

OBJECTIVE

To investigate the potential value of combining maternal factors with multiples of the normal median values of maternal cardiovascular parameters at 35-37 weeks' gestation in the prediction of pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

In 2764 singleton pregnancies maternal characteristics and medical history were recorded; uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable logistic regression analysis was then used to determine if the maternal factors and maternal cardiovascular parameters made a significant contribution to predicting PE and GH. The performance of screening was determined by the area under receiver-operating characteristics curves.

RESULTS

In pregnancies that subsequently delivered with PE or GH, total peripheral resistance and MAP were higher and maternal cardiac output was lower, mainly owing to a decrease in heart rate in PE and a decrease in stroke volume in GH. The increases in total peripheral resistance and MAP were inversely related to gestational age at delivery. The performance of screening for PE and GH achieved by maternal characteristics and medical history was improved by the inclusion of MAP, but not by UtA-PI or maternal cardiovascular parameters.

CONCLUSIONS

In women developing term PE total peripheral resistance and MAP are increased and maternal cardiac output is reduced. However, assessment of maternal cardiac function at 35-37 weeks' gestation is unlikely to improve the performance of screening for PE provided by maternal factors and MAP alone. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Uterine artery pulsatility index at 12, 22, 32 and 36 weeks' gestation in screening for pre-eclampsia

OBJECTIVE

To examine the distribution of uterine artery pulsatility index (UtA-PI) at 12, 22, 32 and 36 weeks' gestation in singleton pregnancies which develop pre-eclampsia (PE) and examine the performance of this biomarker in screening for PE.

METHODS

UtA-PI was measured in 92 712 singleton pregnancies at 11-13 weeks, in 67 605 cases at 19-24 weeks, in 31 741 at 30-34 weeks and in 5523 at 35-37 weeks. Bayes' theorem was used to combine the a-priori risk from maternal characteristics and medical history with UtA-PI. The performance of screening for PE requiring delivery < 32, at 32 + 0 to 36 + 6, < 37 and ≥ 37 weeks' gestation was estimated. The results of combined screening were compared to those of screening by UtA-PI and by maternal factors alone.

RESULTS

In pregnancies that developed PE, UtA-PI was increased and the separation in multiples of the median (MoM) values from normal was greater with earlier, compared to later, gestational age at which delivery for PE became necessary. Additionally, the slope of regression lines of UtA-PI MoM with gestational age at delivery in pregnancies that developed PE increased with increasing gestational age at screening. The detection rate (DR), at a 10% false-positive rate (FPR), for PE delivering < 32 weeks was 71% and 88% with combined screening at 11-13 and 19-24 weeks, respectively, and the DR for PE delivering at 32 + 0 to 36 + 6 weeks was 52%, 63% and 71% with screening at 11-13, 19-24 and 30-34 weeks, respectively. However, the DR of PE delivering ≥ 37 weeks was only about 40%, irrespective of the gestational age at screening. The performance of screening by the approach utilizing Bayes' theorem was superior to that of using a percentile cut-off of UtA-PI for gestational age.

CONCLUSIONS

The performance of combined screening with maternal factors and UtA-PI is superior for detection of early, compared to late, PE and, to a certain extent, improves with advancing gestational age at screening. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Hypertensive pathologies and egg donation pregnancies: Results of a large comparative cohort study

OBJECTIVE

To determine whether egg donation (ED) pregnancies are at higher risk of pregnancy-induced hypertension (PIH) than those achieved by autologous assisted reproductive technology (ART; controls).

DESIGN

Anonymous comparative observational matched cohort study.

SETTING

Assisted reproductive technology centers.

PATIENT(S)

Two hundred seventeen ED and 363 control singleton pregnancies matched at 7-8 weeks (pregnancy date, parity, cycle type [fresh/frozen] and women's age). According to French practice, all women were under 45.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Percentage of PIH for ED versus controls.

RESULT(S)

The groups were comparable (mean age, 34.5). PIH was more frequent during ED pregnancies (17.8% vs. 5.3%), as was preeclampsia (11.2% vs. 2.8%) and eclampsia (1.8% vs. 0.0%). In multivariate analyses, PIH risk increased with ED (odds ratio [OR], 3.92; 95% confidence interval [CI], 1.93-7.97) and women's age (OR, 1.08; 95% CI, 1.00-1.16). No significant effect of previous pregnancies or cycle rank/type was observed.

CONCLUSION(S)

This study had sufficient power to detect doubling of the PIH rate. It was demonstrated that the risk of PIH was tripled for ED versus controls. Even in young women, ED is a risk factor for PIH. An immunological explanation seems most likely, that is, the fetus is fully allogeneic to its mother. This risk must be acknowledged to inform couples and provide careful pregnancy monitoring.

The use of ultrasound and other markers for early detection of preeclampsia

Preeclampsia (PE) is a multisystem disorder of pregnancy classically characterized with the onset of hypertension after 20 weeks gestation in the presence of proteinuria. PE typically affects 2-8% of pregnancies and is a leading cause of maternal and perinatal morbidity and mortality. This article reviews the most effective biomarkers used in first trimester screening for PE. It explores their use both in isolation and as part of an algorithm to yield the best detection rates. Screening by a combination of maternal risk factors, uterine artery Doppler, mean arterial pressure, maternal serum PAPP-A and PlGF can identify about 75% of cases of preterm PE for a false-positive rate of 10%. By identifying these patients at high risk for PE, appropriately tailored antenatal surveillance can be instigated and prophylactic pharmacological interventions can be prescribed to improve placentation and ultimately, the outcome for both the mother and fetus.

Mechanisms of trophoblast migration, endometrial angiogenesis in preeclampsia: The role of decorin

The objective of the present review is to synthesize the information on the cellular and molecular players responsible for maintaining a homeostatic balance between a naturally invasive human placenta and the maternal uterus in pregnancy; to review the roles of decorin (DCN) as a molecular player in this homeostasis; to list the common maladies associated with a break-down in this homeostasis, resulting from a hypo-invasive or hyper-invasive placenta, and their underlying mechanisms. We show that both the fetal components of the placenta, represented primarily by the extravillous trophoblast, and the maternal component represented primarily by the decidual tissue and the endometrial arterioles, participate actively in this balance. We discuss the process of uterine angiogenesis in the context of uterine arterial changes during normal pregnancy and preeclampsia. We compare and contrast trophoblast growth and invasion with the processes involved in tumorigenesis with special emphasis on the roles of DCN and raise important questions that remain to be addressed. Decorin (DCN) is a small leucine-rich proteoglycan produced by stromal cells, including dermal fibroblasts, chondrocytes, chorionic villus mesenchymal cells and decidual cells of the pregnant endometrium. It contains a 40 kDa protein core having 10 leucine-rich repeats covalently linked with a glycosaminoglycan chain. Biological functions of DCN include: collagen assembly, myogenesis, tissue repair and regulation of cell adhesion and migration by binding to ECM molecules or antagonising multiple tyrosine kinase receptors (TKR) including EGFR, IGF-IR, HGFR and VEGFR-2. DCN restrains angiogenesis by binding to thrombospondin-1, TGFβ, VEGFR-2 and possibly IGF-IR. DCN can halt tumor growth by antagonising oncogenic TKRs and restraining angiogenesis. DCN actions at the fetal-maternal interface include restraint of trophoblast migration, invasion and uterine angiogenesis. We demonstrate that DCN overexpression in the decidua is associated with preeclampsia (PE); this may have a causal role in PE by compromising endovascular differentiation of the trophoblast and uterine angiogenesis, resulting in poor arterial remodeling. Elevated DCN level in the maternal blood is suggested as a potential biomarker in PE.

Uterine artery pulsatility index in the three trimesters of pregnancy: effects of maternal characteristics and medical history

OBJECTIVE

To define the contribution of maternal variables that influence the measured uterine artery pulsatility index (UtA-PI) in screening for pregnancy complications.

METHODS

Maternal characteristics and medical history were recorded, and UtA-PI was measured, in women with a singleton pregnancy attending for three routine hospital visits at 11 + 0 to 13 + 6 weeks, 19 + 0 to 24 + 6 weeks and 30 + 0 to 34 + 6 weeks or 35 + 0 to 37 + 6 weeks' gestation. For pregnancies delivering phenotypically normal live births or stillbirths at ≥ 24 weeks' gestation, variables from maternal demographic characteristics and medical history that are important in the prediction of UtA-PI were determined from linear mixed-effects multiple regression.

RESULTS

UtA-PI was measured in 90 484 cases in the first trimester, 66 862 cases in the second trimester and 33 470 cases in the third trimester of pregnancy. Significant independent contributions to UtA-PI were provided by gestational age, maternal age, weight, racial origin and a history of pre-eclampsia (PE) in the previous pregnancy. Random-effects multiple regression analysis was used to define the contribution of maternal variables that influence the measured UtA-PI and express the values as multiples of the median (MoM). The model was shown to provide an adequate fit of MoM values for all covariates both in pregnancies that developed PE and in those that did not.

CONCLUSIONS

A model was fitted to express the measured UtA-PI as MoMs after adjustment for variables from maternal characteristics and medical history that affect this measurement.

Evaluation of inflammatory mediators in the deciduas of pregnant women with pre-eclampsia/eclampsia

OBJECTIVE

The objective was to evaluate some inflammatory mediators, i.e. cytokines that induce and inhibit nitric oxide (NO) synthase, in pregnant women with pre-eclampsia/eclampsia (PE/E) compared to clinically normal patients.

METHODS

Placental fragments were collected from 46 pregnant patients, including 30 clinically normal subjects and 16 women with PE/E, and stored in NP40-containing phosphate buffer in a freezer at -70 °C until the time of solubilization. Cytokines IL-4, IL-10, IL-13, TNF-α and IFN-γ were assayed by ELISA and NO was estimated by the Griess reaction after reduction.

RESULTS

Patients with PE/E presented significantly lower placental levels of IL-10 and IL-3 than the control group (p < 0.05). On the other hand, IL-4, TNF-α and IFN-γ levels were similar on the two groups, whereas nitrite/nitrate levels were significantly lower in the PE/E group. A higher inflammatory balance was observed in patients with PE/E compared to normal subjects (p < 0.05).

CONCLUSION

Patients with PE/E present lower levels of Th2 cytokines associated with a pro-inflammatory balance as evaluated by the IL-10/TNF-α ratio, as well as lower nitrite/nitrate levels, than controls.

Early prediction of preeclampsia

Effective screening for the development of early onset preeclampsia (PE) can be provided in the first-trimester of pregnancy. Screening by a combination of maternal risk factors, uterine artery Doppler, mean arterial pressure, maternal serum pregnancy-associated plasma protein-A, and placental growth factor can identify about 95% of cases of early onset PE for a false-positive rate of 10%.

Correlation of Placental Pathology with Perinatal Brain Injury

The purpose of placental pathology is to explain adverse clinical outcomes. One of the most tragic of these outcomes is perinatal brain injury with subsequent neurodisability. Findings in the placenta can play an important role in documenting sentinel events, uncovering clinically silent thromboinflammatory disease processes, revealing developmental alterations in functional reserve, and suggesting alterations in related maternal and fetal physiology. These findings, when integrated with clinical data, provide a plausible explanation for an otherwise unexpected outcome and can be helpful for treating physicians and family members.

hCG, the wonder of today's science

BACKGROUND

hCG is a wonder. Firstly, because hCG is such an extreme molecule. hCG is the most acidic glycoprotein containing the highest proportion of sugars. Secondly, hCG exists in 5 common forms. Finally, it has so many functions ranging from control of human pregnancy to human cancer. This review examines these molecules in detail.

CONTENT

These 5 molecules, hCG, sulfated hCG, hyperglycosylated hCG, hCG free beta and hyperglycosylated free beta are produced by placental syncytiotrophoblast cells and pituitary gonadotrope cells (group 1), and by placental cytotrophoblast cells and human malignancies (group 2). Group 1 molecules are both hormones that act on the hCG/LH receptor. These molecules are central to human menstrual cycle and human pregnancy. Group 2 molecules are autocrines, that act by antagonizing a TGF beta receptor. These molecules are critical to all advanced malignancies.

CONCLUSIONS

The hCG groups are molecules critical to both the molecules of pregnancy or human life, and to the advancement of cancer, or human death.

hCG, five independent molecules

INTRODUCTION

The hCG amino acid sequence supports 5 glycoproteins. All are called hCG forms. This review examines all 5 molecules, the hormone as produced by the placental syncytiotrophoblast cells, the sulfated hormone produced by the pituitary gonadotrope cells, the hyperglycosylated hCG autocrine made by placental cytotrophoblast cells, and the autocrine cancer promoters hyperglycosylated hCG, hCGß and hyperglycosylated hCGß as made by all malignancies. This review examines all the molecules and multiple proven functions, ranging from evolution to cancer promotion to hormone action.

RESULTS AND DISCUSSION

hCG forms are critical super-growth factors in humans, with an exceptional wide range of functions.

Epidemiological studies on primipaternity and immunology in preeclampsia--a statement after twelve years of workshops

Hypertensive disorders of pregnancy (HDP) represent 10% of human births globally and the major complication preeclampsia has a 3-5% prevalence. The etiology of HDP remains uncertain; however, major advances have been made over the last 25 years. The Seventh International Workshop on Reproductive Immunology, Immunological Tolerance and Immunology of Preeclampsia 2010 celebrated its 12th Anniversary in Tioman Island in 2010. Over this period, these seven workshops have contributed extensively to immunological, epidemiological, anthropological, and even vascular debates. The defect of trophoblastic invasion encountered in preeclampsia, intra-uterine growth restriction, and to some extent preterm labor, was understood only at the end of the 1970s. On the other hand, clinical and epidemiological findings at the end of the 20th century permitted us to apprehend that "preeclampsia, the disease of primiparae" may well be a disease of first pregnancy for a couple. Among the important advances, reproductive immunology is certainly the topic where knowledge has exploded in the last decade. This paper relates some major steps in the comprehension of this disease and provides a review of epidemiological studies on the "primipaternity paradigm". It focuses on the relevance of new developments and new concepts in immunology. At the beginning of the 21st century we are possibly closer than ever to understanding the etiology of this obstetrical enigma and also the pathophysiology of global endothelial inflammation in preeclamptic women. In this quest, reproductive immunology will certainly emerge as one of the main players.

Deep trophoblast invasion and spiral artery remodelling in the placental bed of the chimpanzee

Deep trophoblast invasion is usually considered to be a unique feature of human placentation as compared to other primates. Because of the occasional occurrence of preeclampsia in great apes, which in the human is associated with impaired deep invasion, this uniqueness may be questioned. The availability of two well-documented pregnant chimpanzee uteri in the Hubrecht Collection (Museum für Naturkunde, Berlin) allowed us to evaluate the extent of trophoblast invasion in this species. By adjusting currently used protocols, we obtained successful immunohistochemical staining for cytokeratin and α-actin, as well as Ulex europaeus agglutinin 1 (UEA1) lectin staining, in this archival material. In both specimens interstitial trophoblast invasion had occurred in both decidua and myometrium. Because of a lack of published data on fetal growth for this species, fetal sizes (7cm and 13cm) could not be strictly related to gestational ages and thus be compared with the time-course of human trophoblast invasion. However, since the earlier specimen did not show any endovascular trophoblast invasion in spiral arteries - in contrast to pregnant human uteri with equivalent fetal sizes - endovascular migration seems to begin at a different gestational age in the chimpanzee. In the later specimen endovascular trophoblast was associated with spiral artery remodelling in the inner myometrium, and this invasion was extended to include a radial artery, which at that stage still showed relatively intact vascular smooth muscle and elastic lamina. We conclude that invasion depth and spiral artery remodelling are basically similar in chimpanzees and humans, although the seemingly different time of onset may have implications for uteroplacental oxygen supply and fetal development.

Turning the pyramid of prenatal care

The current approach to prenatal care, which involves visits at 16, 24, 28, 30, 32, 34 and 36 weeks and then weekly until delivery, was established 80 years ago. The high concentration of visits in the third trimester implies, firstly, that most complications occur at this late stage of pregnancy and, secondly, that most adverse outcomes are unpredictable during the first or even second trimester. This review presents evidence that many pregnancy complications can now be predicted at an integrated first hospital visit at 11-13 weeks by combining data from maternal characteristics and history with findings of biophysical and biochemical tests. It is therefore proposed that the traditional pyramid of care should be inverted with the main emphasis placed in the first rather than third trimester of pregnancy.

Maternal thyroid function at 11 to 13 weeks of gestation and subsequent development of preeclampsia

OBJECTIVE

To determine if maternal thyroid function in the first trimester is altered in pregnancies that subsequently develop preeclampsia (PE).

METHODS

Mean arterial pressure (MAP), uterine artery pulsatility index (PI) maternal serum thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) at 11 to 13 weeks of gestation were measured in 102 singleton pregnancies that subsequently developed PE, and the values were compared to the results of 4318 normal pregnancies.

RESULTS

In both the PE groups that required delivery before 34 weeks (early-PE) and the late-PE group, compared with the unaffected group, the median MAP multiple of the normal median (MoM) and uterine artery PI MoM were significantly increased. In late-PE but not in early-PE, compared with the unaffected group, the median TSH MoM was significantly increased and the median FT4 MoM was decreased. Logistic regression analysis demonstrated that TSH MoM provided a significant contribution in the prediction of late-PE.

CONCLUSION

Impaired thyroid function may predispose to the development of late-PE, and measurement of maternal serum TSH can improve the prediction of late-PE provided by a combination of factors in the maternal history and the measurements of MAP and uterine artery PI.

Hypertensive disorders in pregnancy: screening by biophysical and biochemical markers at 11-13 weeks

OBJECTIVE

To examine the performance of screening for pre-eclampsia (PE) and gestational hypertension (GH) by a combination of maternal factors and various biophysical and biochemical markers at 11-13 weeks' gestation.

METHODS

This was a case-control study of 26 cases of early PE, 90 of late PE, 85 of GH and 201 unaffected controls. Maternal history was recorded, the uterine artery with the lowest pulsatility index (L-PI) and mean arterial pressure (MAP) were measured and stored plasma and serum were analyzed for placental growth factor (PlGF), inhibin-A, activin-A, tumor necrosis factor receptor-1, matrix metalloproteinase-9, pentraxin-3 and P-selectin.

RESULTS

Multivariate logistic regression analysis demonstrated that significant prediction for early PE was provided by maternal factors, MAP, uterine artery L-PI and serum PlGF. Significant prediction of late PE was provided by maternal factors, MAP, uterine artery L-PI, PlGF, activin-A and P-selectin. For GH significant prediction was provided by maternal factors, MAP, uterine artery L-PI and activin-A. In screening by a combination of maternal factors, biophysical and biochemical markers the estimated detection rates, at a 5% false-positive rate, were 88.5% (95% CI, 69.8-97.4%) for early PE, 46.7% (95% CI, 36.1-57.5%) for late PE and 35.3% (95% CI, 25.2-46.4%) for GH.

CONCLUSION

Combined biophysical and biochemical testing at 11-13 weeks could effectively identify women at high risk for subsequent development of hypertensive disorders in pregnancy.

Hypertensive disorders in pregnancy: screening by uterine artery Doppler imaging and blood pressure at 11-13 weeks

OBJECTIVES

To examine the performance of screening for hypertensive disorders in pregnancy at 11-13 weeks by a combination of the maternal history, uterine artery Doppler imaging and blood pressure.

METHODS

This was a prospective screening study for pre-eclampsia (PE) requiring delivery before 34 weeks (early PE), late PE and gestational hypertension (GH) in women attending for their routine first hospital visit in pregnancy at 11 + 0 to 13 + 6 weeks of gestation. Maternal history was recorded, color flow Doppler imaging was used to identify the uterine artery with the lowest pulsatility index (L-PI) and automated devices were used to measure the mean arterial pressure (MAP). The performance of screening for PE and GH by a combination of the maternal factor-derived a-priori risk, the uterine artery L-PI and MAP was determined.

RESULTS

There were 8061 (96.4%) cases unaffected by PE or GH, 165 (2.0%) that developed PE including 37 that required delivery before 34 weeks (early PE) and 128 with late PE, and 140 (1.7%) that developed GH. The MAP was higher in early PE, late PE and GH than in the unaffected group (P < 0.0001), and in early PE than in GH (P = 0.002). The uterine artery L-PI was significantly higher in early PE and late PE than in the unaffected group (P < 0.0001), in early PE than late PE or GH (P < 0.0001), and in GH than in the unaffected group (P = 0.014). In screening by a combination of the maternal factor-derived a-priori risk, uterine artery L-PI and MAP, the estimated detection rate at a 10% false-positive rate was 89.2% (95% CI, 74.6-96.9%) for early PE, 57.0% (95% CI, 48.0-65.7%) for late PE and 50.0% (95% CI, 41.4-58.6%) for GH.

CONCLUSIONS

Effective screening for hypertensive disorders in pregnancy is provided by a combination of maternal history, uterine artery Doppler imaging and blood pressure at 11-13 weeks.

Hypertensive disorders in pregnancy: screening by uterine artery Doppler at 11-13 weeks

OBJECTIVES

To examine the performance of screening for hypertensive disorders in pregnancy by a combination of the maternal factor-derived a-priori risk with the uterine artery (UtA) pulsatility index (PI) and to determine whether it is best in such screening to use the mean PI of the two arteries, the highest PI or the lowest PI.

METHODS

This was a prospective screening study for pre-eclampsia (PE) requiring delivery before 34 weeks (early PE), late PE and gestational hypertension (GH) in women attending their routine first hospital visit in pregnancy at 11 + 0 to 13 + 6 weeks of gestation. Maternal history was recorded and color flow Doppler imaging was used to measure the left and right UtA-PI. The performance of screening for PE and GH by a combination of the maternal factor-derived a-priori risks determined in a previous study and the UtA-PI was assessed.

RESULTS

There were 8061 (96.4%) cases unaffected by PE or GH, 37 (0.4%) that developed early PE, 128 (1.5%) with late PE and 140 (1.7%) with GH. The lowest, mean and highest UtA-PI were significantly higher in early PE and late PE than in the controls (P < 0.0001) and in early PE than late PE (P < 0.0001). The lowest UtA-PI was higher in GH than in controls (P = 0.014). The best performance in screening was provided by the lowest PI. The detection rate of early PE at a 10% false-positive rate increased from 47% in screening by maternal factors alone to 81% in screening by maternal factors and the lowest UtA-PI. The respective detection rates for late PE increased from 41% to 45% and those for GH increased from 31% to 35%.

CONCLUSIONS

The patient-specific risk for PE and GH can be derived by combining the disease-specific maternal factor-derived a-priori risk with the measurement of the lowest UtA-PI in a multivariate regression model.

hCG and hyperglycosylated hCG in the establishment and evolution of hemochorial placentation

The evolution of regular chorionic gonadotropin (CG) and hyperglycosylated CG are linked with the evolution of hemochorial placentation in primates. Recent research with humans shows that regular CG promotes spiral artery angiogenesis and hyperglycosylated CG controls invasion by implanting trophoblast cells. It is inferred that the evolution of regular CG and hyperglycosylated CG in early simian primates, the first species to produce these CG forms, established hemochorial placentation in this species. The circulating half-lives, and thus the circulating concentrations, of regular CG and hyperglycosylated CG increased in advanced simian primates and increased further in humans, seemingly causing greater myometrial invasion and superior angiogenesis in hemochorial placentation in advanced primates and humans. Advanced hemochorial placentation is associated with relatively high proportions of pregnancy failures in humans. This can be explained by considering human implantation inadequate in terms of invasion requirements. The demanding implantation required by the human embryo is seemingly dependent on adequate production of hyperglycosylated CG. Failures in hemochorial placentation invasion lead to anoxia and cause preeclampsia and eclampsia uniquely in humans, which can also be attributed to inadequate hyperglycosylated CG signaling. We propose here that inadequate regular CG and hyperglycosylated CG molecules are the evolutionary causes of these obstetric complications in humans.

New discoveries on the biology and detection of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) is a glycoprotein hormone comprising 2 subunits, alpha and beta joined non covalently. While similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents, rather than as a single molecule like LH and the other glycoprotein hormones. These are regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglycosylated hCG. For 88 years regular hCG has been known as a promoter of corpus luteal progesterone production, even though this function only explains 3 weeks of a full gestations production of regular hCG. Research in recent years has explained the full gestational production by demonstration of critical functions in trophoblast differentiation and in fetal nutrition through myometrial spiral artery angiogenesis. While regular hCG is made by fused villous syncytiotrophoblast cells, extravillous invasive cytotrophoblast cells make the variant hyperglycosylated hCG. This variant is an autocrine factor, acting on extravillous invasive cytotrophoblast cells to initiate and control invasion as occurs at implantation of pregnancy and the establishment of hemochorial placentation, and malignancy as occurs in invasive hydatidiform mole and choriocarcinoma. Hyperglycosylated hCG inhibits apoptosis in extravillous invasive cytotrophoblast cells promoting cell invasion, growth and malignancy. Other non-trophoblastic malignancies retro-differentiate and produce a hyperglycosylated free beta-subunit of hCG (hCG free beta). This has been shown to be an autocrine factor antagonizing apoptosis furthering cancer cell growth and malignancy. New applications have been demonstrated for total hCG measurements and detection of the 3 hCG variants in pregnancy detection, monitoring pregnancy outcome, determining risk for Down syndrome fetus, predicting preeclampsia, detecting pituitary hCG, detecting and managing gestational trophoblastic diseases, diagnosing quiescent gestational trophoblastic disease, diagnosing placental site trophoblastic tumor, managing testicular germ cell malignancies, and monitoring other human malignancies. There are very few molecules with such wide and varying functions as regular hCG and its variants, and very few tests with such a wide spectrum of clinical applications as total hCG.

Etiology of preeclampsia: maternal vascular predisposition and couple disease--mutual exclusion or complementarity?

Developed countries represent 20% of the population in the world, but only 12% of human births annually, while 98% of medical publications are issued from these areas. What we can read on preeclampsia is correct, but only for 12% of human pregnancies! In addition, reproductive patterns in the developed world, but only for the last three decades, are different from elsewhere and during the first 70 years of the 20th century. A major difference is in the number of children in families but also, and mainly, in the ages at first pregnancies in primiparae (approaching now 30 years in many developed countries). This is probably why current epidemiological data seem different than that of the 20th century. The purpose of this article is to analyse to what extent the 'primipaternity model' may give clues for the comprehension of epidemiological descriptions past and present--and, indeed, it works in many respects. However, it is evident also that a proportion of preeclampsia cases cannot be explained by paternity patterns, and vascular disease predisposition in women (diabetes, obesity, thrombophilias, etc.) evidently comes into play. For these latter, maternal age is also strongly associated with these complications. Here, we reflect on what can be respective parts of the disease in preeclamptic couples, and on preeclampsia as a marker of subjects susceptible to vascular disease.

Association Between Infant Birth Weight and Maternal Cardiovascular Risk Factors in the Health, Aging, and Body Composition Study

PURPOSE

Mothers who deliver a low-birth-weight (LBW) infant may themselves be at excess risk for cardiovascular disease. We investigated whether older women who bore LBW infants had higher blood pressure, lipid, glucose, insulin, interleukin 6 (IL-6), and C-reactive protein concentrations, and pulse wave velocity compared to women with normal-weight births.

METHODS

Participants were 446 women with a mean age of 80 years and 47% black. Women reported birth weight and complications for each pregnancy. Analysis was limited to first births not complicated by hypertension or preeclampsia.

RESULTS

Women who had delivered a first-birth infant weighing less than 2500 g had a lower body mass index (BMI) compared with women with a normal-weight (>or=2500 g) infant (26.7 versus 28.4 kg/m2; p=0.02), but they had a larger abdominal circumference for BMI (97.9 versus 95.5 cm; p=0.05). They also were marginally more likely to be administered antihypertensive medication (p=0.06). After adjustment for BMI, race, and age, women with a history of a small infant had elevations in systolic blood pressure (p=0.05) and greater IL-6 levels (p=0.02) and were more insulin resistant (p=0.05) compared with women with a normal-weight infant.

CONCLUSIONS

These findings suggest that a history of LBW delivery identifies women with elevated cardiovascular risk factors.

The Uterine Spiral Arteries In Human Pregnancy: Facts and Controversies

Uterine spiral arteries play a vital role in supplying nutrients to the placenta and fetus, and for this purpose they are remodelled into highly dilated vessels by the action of invading trophoblast (physiological change). Knowledge of the mechanisms of these changes is relevant for a better understanding of pre-eclampsia and other pregnancy complications which show incomplete spiral artery remodelling. Controversies still abound concerning different steps in these physiological changes, and several of these disagreements are highlighted in this review, thereby suggesting directions for further research. First, a better definition of the degree of decidua- versus trophoblast-associated remodelling may help to devise a more adequate terminology. Other contestable issues are the vascular plugging and its relation with oxygen, trophoblast invasion from the outside or the inside of the vessels (intravasation versus extravasation), the impact of haemodynamics on endovascular migration, the replacement of arterial components by trophoblast, maternal tissue repair mechanisms and the role of uterine natural killer (NK) cells. Several of these features may be disturbed in complicated pregnancies, including the early decidua-associated vascular remodelling, vascular plugging and haemodynamics. The hyperinflammatory condition of pre-eclampsia may be responsible for vasculopathies such as acute atherosis, although the overall impact of such lesions on placental function is far from clear. Several features of the human placental bed are mirrored by processes in other species with haemochorial placentation, and studying such models may help to illuminate poorly understood aspects of human placentation.

Plasma granulysin concentrations and preeclampsia risk

OBJECTIVE

Epidemiological, clinical and histological data suggest intriguing similarities between preeclampsia and graft-host-rejection. Granulysin, a novel biomarker of overall cellular immunity, is secreted by natural killer cells and cytotoxic T lymphocytes, which are associated with graft-host-rejection. Plasma granulysin was elevated in Japanese preeclamptic women.

DESIGN AND METHODS

50 preeclampsia cases and 50 normotensive controls (USA) were studied. Plasma granulysin at delivery was determined using enzyme immunoassay. Logistic regression procedures were used to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Granulysin were elevated in preeclampsia cases compared with controls (3.01+/-0.18 vs. 2.22+/-0.14 ng/mL, p<0.01). After adjusting for age, body-mass-index and race, women with higher granulysin concentrations (> or =1.89 ng/mL) experienced a 2.9-fold (95%CI 1.1-7.8) increased preeclampsia risk compared with women with lower granulysin (<1.89 ng/mL).

CONCLUSIONS

These data offer further evidence of a predominant Th1 immune status associated with preeclampsia. Prospective studies are needed to determine whether granulysin is elevated early in pregnancy.

Late sporadic miscarriage is associated with abnormalities in spiral artery transformation and trophoblast invasion

Trophoblast invasion of uterine decidua and myometrium, and spiral artery transformation, are essential for the development of normal pregnancy; this process is impaired in pre-eclampsia, fetal growth restriction, and pre-term labour. The hypothesis that late miscarriage is associated with reduced trophoblast invasion and spiral artery transformation was tested in a large series of placental bed biopsies containing decidua and myometrium from late, karyotyped, embryonic miscarriage (>or=13 weeks' gestation; n = 26; n = 96 spiral arteries) and gestationally matched ultrasound-dated normal pregnancies (n = 74; n = 236 spiral arteries). Cryostat sections were immunostained using an avidin-biotin peroxidase technique for cytokeratin, desmin, and von Willebrand factor to detect trophoblast, myometrium, and vascular smooth muscle and endothelium, respectively. Trophoblast invasion and individual features of spiral artery transformation were assessed and analysed using a logistic regression model. Compared with normal pregnancy, myometrial spiral arteries in late miscarriage showed reduced endovascular (4% vs. 31%, p = 0.001) and intramural trophoblast (76% vs. 88%, p = 0.05), and less extensive fibrinoid change (4% vs. 18%, p = 0.01). In contrast, endovascular trophoblast in decidual spiral arteries was increased (40% vs. 66%, p = 0.04). These findings suggest that, in common with pre-eclampsia, late sporadic miscarriage may be associated with reduced trophoblast invasion and inadequate transformation of myometrial spiral arteries.

Placental function in development and disease

The placenta is an organ that clinicians and embryologists would all agree is important for pregnancy success. Unfortunately, however, they too often ignore it when they are exploring causes for embryonic, fetal and perinatal complications. The core function of the placenta is to mediate the transport of nutrients between the maternal and fetal circulation, but it also has critical endocrine functions that alter different maternal physiological systems in order to sustain pregnancy. Both its development and ongoing functions can be dynamically regulated by environmental factors, including nutrient status and tissue oxygenation. In recent years, mainstream attention has begun to shift onto the placenta and it is now becoming clear that placental pathology is associated with several complications in human and animal pregnancies, including embryonic lethality, fetal growth restriction, pre-eclampsia and the high rates of fetal deaths observed after nuclear transfer (cloning).

Persistency of high proinflammatory cytokine levels from colostrum to mature milk in preeclampsia

OBJECTIVES

Recent evidence suggests a role of an excessive maternal inflammatory response in the pathogenesis of preeclampsia. Whether this imbalance can be transferred from mother to breast milk remains to be established.

DESIGN AND METHODS

15 preeclamptic and 15 healthy pregnant women were recruited in this study. Colostrum and milk samples were collected postpartum in the first 48 h and at 30 days, respectively. Samples were analyzed for interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)-alpha and soluble IL-2R (sIL-2R) levels with chemiluminescence enzyme immunometric assays.

RESULTS

Colostrum cytokine levels corrected for gestational age and type of delivery were not significantly different in the two groups. Cytokine levels significantly decreased in mature milk versus colostrum in the control group (P < 0.05), but did not significantly decrease in the preeclampsia group (P > 0.05), except for TNF-alpha (P < 0.05). Mature milk IL-8 and TNF-alpha levels were higher in the preeclampsia group versus controls (P < 0.05).

CONCLUSION

Results of this study show that proinflammatory cytokines in breast milk exhibit biological variation at different periods of human lactation. In preeclampsia, high cytokine levels persist at least for 30 days. These results suggest that preeclampsia may affect milk cytokine balance and offer an immunological signal for the host defense in high-risk neonates.

Priming and remodelling of human placental bed spiral arteries during pregnancy--a review

It is now well known that in order to establish human hemochorial placentation and to provide a progressive increase in blood supply to the growing fetus, the uterine spiral arteries must undergo considerable alterations. This physiological modification is thought to be brought about by the interaction of invasive cytotrophoblast with the spiral artery vessel wall. Despite intensive research our understanding of the mechanisms that control human trophoblast invasion in normal, let alone abnormal pregnancy, are still poorly understood. This is partly due to difficulties in obtaining "true" placental bed biopsies and most investigators have relied on in vitro models of trophoblast invasion. Clearly interpretation of such studies must be tempered with a degree of caution. This review outlines why the placental bed is important, how we can sample and study it, what morphology actually occurs in the placental bed spiral arteries during pregnancy and then briefly summarise the findings on the placental bed in pre-eclampsia.

Immunological Similarities between Implantation and Pre-eclampsia

PROBLEM

Cytokines are involved in implantation success and failure. We envisage that they could be similarly involved in pre-eclampsia (PE).

MATERIALS AND METHODS

First, we review the primipaternity and primiparity concepts and then why natural killer (NK) cells are involved in implantation. We stress that the common event in all PE is vascular remodelling.

RESULTS AND CONCLUSION

We conclude that PE could involve cytokine and/or NK dysfunctions, and propose a working hypothesis.

Direct placental effects of cigarette smoke protect women from pre-eclampsia: the specific roles of carbon monoxide and antioxidant systems in the placenta

Pre-eclampsia is a hypertensive disorder of pregnancy characterized by shallow placentation, inadequate placental perfusion, localized placental oxidative stress, a heightened maternal inflammatory response and subsequent maternal endothelial dysfunction. This pathophysiology leads to an increase in maternal blood pressure, edema and proteinurea. Interestingly, women who smoke cigarettes throughout pregnancy are at a 33% reduced risk of developing this disorder. The exact mechanisms through which cigarette smoke reduces the risk of pre-eclampsia are not yet understood. We propose that cigarette smoke reduces the risk of developing pre-eclampsia via direct placental effects. In this review we will address, and provide evidence for, our specific hypotheses that: (a) CO increases trophoblast invasion and spiral arteriole remodeling; (b) CO decreases a localized inflammatory response at the level of the decidua; (c) CO increases utero-placental, intra-placental and feto-placental blood flow; (d) CO decreases hypoxia-induced apoptosis of the syncitiotrophoblast layer; (e) CO activates hemoproteins involved in normal endothelial functioning normally acted upon by NO; (f) compound(s) within cigarette smoke result in upregulation of antioxidant systems within the placenta. These various mechanisms of action must be further examined as they may provide valuable keys to novel therapeutic design in the realm of pre-eclampsia research.

Interaction of Jar choriocarcinoma cells with endothelial cell monolayers

During human pregnancy the uterine spiral arteries are invaded by placental trophoblasts which replace the endothelial cells that line the non-pregnant spiral arteries and transform these vessels into large-bore conduits enabling adequate perfusion of the placenta with maternal blood. Failure of this process may predispose to preeclampsia and fetal growth restriction [Brosens I, Robertson WB, Dixon HG. The physiological response of the vessels of the placental bed to normal pregnancy. Journal of Pathology and Bacteriology 1967;93:569-79; Khong TY, De Wolf F, Robertson WB, Brosens I. Inadequate maternal vascular response to placentation in pregnancies complicated by pre-eclampsia and by small-for-gestational age infants. British Journal of Obstetrics and Gynaecology 1986;93:1049-59]. There is a paucity of data on the role of maternal endothelial cells in this process. In this study we investigated the cellular interactions between trophoblast-derived Jar cells and endothelial cells (HUVECs and HMEC-1). The effect of coculturing Jar cells with endothelial cell monolayers was determined by confocal microscopy, DNA fragmentation assay and flow cytometry. We demonstrated that Jar cells migrate into focal areas in endothelial cell monolayers, where they induce endothelial cell death and, then phagocytose the dead endothelial cells. Our results suggest that endothelial cells may not simply be passive targets for invading trophoblasts during the remodeling of the spiral arteries.

Preeclampsia and human reproduction. An essay of a long term reflection

Hypertensive disorders of pregnancy (HDP: pregnancy-induced hypertension, preeclampsia, eclampsia) affect approximately 10% of human births. Women are at increased risk for HDP during their first conception; and/or when the conception is with a new partner (new paternity); when conception occurs very shortly after the beginning of their sexual relationship. A primary cause of preeclampsia is the defect of the normal human-specific deep endovascular invasion of trophoblast, which is a consequence of the nutritional demands of growth of the human fetal brain. The occurrence of preeclampsia represents a reproductive disadvantage unique to humans compared with other mammals. As such, it may have played a significant role in shaping human reproduction and, therefore, human sexuality. This deep implantation/preeclampsia phenomenon may explain many anthropological mysteries of human sexuality that do not exist in other mammalian species (and primates). These include: very low fertility rate, concealed ovulation, all year long 'apparent-waste-of-efficiency' sexuality, absence of sperm competition in human females at the time of conception, and the unexplained testicle size in human males compared with relevant primates. Further, this deep trophoblastic implantation (and its failure in preeclampsia) in humans might be a decisive condition of hominization between great apes and all the other Homo genuses. This frontier might even have occurred inside these Homo lineages: because of their relatively small brains, the first species of Homo might not have presented the deep trophoblastic invasion described in Homo sapiens.