Placenta weight percentile curves for singleton and twins deliveries

Outcomes of dichorionic twin pregnancies with fused versus separate placentas

PURPOSE

In a certain proportion of dichorionic twin pregnancies, the two placentas are fused. The clinical significance of this finding remains unclear. Our objective was to compare outcomes of dichorionic twin pregnancies with fused versus separate placentas as determined on first-trimester ultrasound.

METHODS

Retrospective study of patients with dichorionic twins followed at a tertiary center between 2014 and 2022. The co-primary outcomes were fetal growth restriction and preeclampsia. Associations between fused placentas and the study outcomes were estimated using multivariable Poisson regression and were reported as adjusted relative risk (aRR) with a 95%-confidence interval (CI).

RESULTS

Of the 328 eligible patients, 175 (53.4%) and 153 (46.6%) had fused and separate placentas, respectively. Compared with pregnancies with separate placentas, patients with fused placentas had a lower risk of preeclampsia [aRR 0.48 (95%-CI 0.24-0.97)] but a higher risk of fetal growth restriction [aRR 1.23 (95%-CI 1.02-1.48)] and admission to the neonatal intensive care unit [aRR 1.31 (95%-CI 1.01-1.71)]. In addition, pregnancies with fused placentas were more likely to have a total placental weight below the 10th percentile than those with separate placentas [aRR 1.93 (95%-CI 1.16-3.21)].

DISCUSSION

Dichorionic twin pregnancies with fused placentas have a lower risk of preeclampsia but are more likely to be complicated by fetal growth restriction, observations that may be attributed to the lower total placentas mass in pregnancies with fused compared with separate placentas. Fused placentas can be used as a potential biomarker for the prediction of pregnancy complications in dichorionic twin pregnancies.

Reference Values for Placental Weight and Placental:Fetal Weight Ratio in a Swedish Population

INTRODUCTION

There is important clinical information from placental weight and its ratio to the fetal weight. The aim with this study was to establish reference values for the placental weight and the placental:fetal weight ratio for gestational weeks 13-43 in a Swedish population.

MATERIALS AND METHODS

Cases were retrospectively collected from the database used at the Pathology Department at Karolinska University Hospital and information about the placental weight, fetal weight, and gestational age was retrieved. Conditions, which could affect the placental- or fetal weight were excluded. Thereafter percentile curves were calculated for the placental weight and the placental:fetal weight ratio for gestational weeks.

RESULTS

A total of 730 cases were included and percentile curves for the placental weight for gestational week 13-43 and placental:fetal weight ratio for gestational week 18-43 are presented.

CONCLUSIONS

Reference values for post fixation placental weight and its ratio to fetal weight for a Swedish population are presented. The reference values are lower than the current reference values used in our institution, and this will be of importance when interpreting findings after placental examination.

Placental weight percentile curves in a Danish population

INTRODUCTION

The role of the placenta is to transport oxygen and nutrients to the fetus, and a well-functioning placenta is vital to fetal health. Our aim was to develop placental weight percentile curves adjusted by gestational age, and stratified by major maternal comorbidities.

MATERIAL AND METHODS

The study was a population study in a Danish cohort. Data was drawn from The Medical Birth Register and the National Patient Register. We included singleton births with a gestational age of 22 + 0 to 42 + 6 weeks. We excluded multiple pregnancies, stillbirths and retained placentas. A total of 611 418 placentas were included. Percentile line graphs were created in groups of all placentas, hypertensive disorders and diabetic disorders.

RESULTS

Tables and figures are presented for placental weight percentile curves according to gestational age for all placentas, hypertensive disorders and diabetic disorders, respectively. Placental weight was generally higher in the diabetic placentas, and lower in the hypertensive placentas.

CONCLUSIONS

These percentile curves may serve as a reference for other populations, and may be useful for other studies investigating the role of the placenta in relation to pregnancy outcomes, and health in later life.

Asymmetric growth-limiting development of the female conceptus

Introduction

Sex differences in prenatal growth may contribute to sex-dependent programming effects on postnatal phenotype.

Methods

We integrated for the first time phenotypic, histomorphological, clinico-chemical, endocrine and gene expression analyses in a single species, the bovine conceptus at mid-gestation.

Results

We demonstrate that by mid-gestation, before the onset of accelerated growth, the female conceptus displays asymmetric lower growth compared to males. Female fetuses were smaller with lower ponderal index and organ weights than males. However, their brain:body weight, brain:liver weight and heart:body weight ratios were higher than in males, indicating brain and heart 'sparing'. The female placenta weighed less and had lower volumes of trophoblast and fetal connective tissue than the male placenta. Female umbilical cord vessel diameters were smaller, and female-specific relationships of body weight and brain:liver weight ratios with cord vessel diameters indicated that the umbilico-placental vascular system creates a growth-limiting environment where blood flow is redistributed to protect brain and heart growth. Clinico-chemical indicators of liver perfusion support this female-specific growth-limiting phenotype, while lower insulin-like growth factor 2 (IGF2) gene expression in brain and heart, and lower circulating IGF2, implicate female-specific modulation of key endocrine mediators by nutrient supply.

Conclusion

This mode of female development may increase resilience to environmental perturbations in utero and contribute to sex-bias in programming outcomes including susceptibility to non-communicable diseases.

Placental size at gestational week 36: Comparisons between ongoing pregnancies and deliveries

INTRODUCTION

We aimed to compare placental size and placental size relative to fetal size (ratio) in ongoing pregnancies examined by magnetic resonance imaging (MRI) at gestational week 36 with placental size among all deliveries at gestational week 36 during the same time period.

MATERIAL AND METHODS

Ongoing unselected singleton pregnancies (n = 89) were examined by MRI at median gestational week 36+5 days during 2017-2018, and placental and fetal volumes (cm3 ) were calculated. The placental size and ratio in ongoing pregnancies were compared with placental size and ratio among all deliveries in Norway at gestational week 36 (median gestational week 36+4 days) during 2016-2019 (n = 5582). For comparison of size, we converted volume (cm3 ) in ongoing pregnancies into grams as: cm3  × 1.05 (density of placental and fetal tissue).

RESULTS

In ongoing pregnancies, median placental size was 873  (interquartile range [IQR] 265) grams and median size of all delivered placentas was 613 (IQR 290) grams. Placental size was smaller among the delivered placentas independent of delivery mode: 760 (IQR 387) grams among elective cesarean deliveries (n = 465) and 590 (IQR 189) grams among vaginal deliveries after spontaneous onset of labor (n = 2478). Median ratio in ongoing pregnancies was higher than among deliveries: 0.31 (IQR 0.08) vs 0.21 (IQR 0.08). The ratio was higher in ongoing pregnancies independent of delivery mode: 0.24 (IQR 0.17) among elective cesarean deliveries vs 0.21 (IQR 0.05) among vaginal deliveries after spontaneous onset of labor.

CONCLUSIONS

The placenta is larger in ongoing pregnancies than among deliveries. This finding suggests that placental size decreases during labor and delivery, possibly by transfer of blood to the fetus. Our finding also suggests that reference values of placental size based on delivered placentas are not valid for ongoing pregnancies.

Placenta previa in in vitro fertilization and unassisted pregnancies-is there a difference in perinatal outcomes and placental histology?

INTRODUCTION

In-vitro-fertilization (IVF) is an independent risk factor for placenta previa (PP). Our aim was to study this link by comparing the clinical characteristics and placental histology of pregnancies complicated by PP in IVF versus unassisted pregnancies.

METHODS

A retrospective-cohort study of deliveries with PP between 2008 and 2021. Placental histology, obstetric and neonatal outcomes were compared between IVF and unassisted pregnancies. Included, were singleton deliveries complicated by PP at gestational weeks (GA) >24.

RESULTS

A total of 182 pregnancies were included - 23 IVF pregnancies (IVF group) and 159 unassisted pregnancies (Control group). The control group was characterized by higher gravidity (p = .007) and parity (p < .001) and a trend of more past cesarean deliveries, whereas the IVF group- by a higher rate of nulliparity (p < .001) and diabetes mellitus (p = .04). The control group was characterized by a higher rate of placental weight below the 10th percentile (47.8 versus 13.9%, p = .001) and by a trend of a lower overall placental weight. No differences were noted in maternal and fetal vascular lesions.

DISCUSSION

While PP in non-assisted pregnancies is probably associated with previous CDs, in IVF it is more "sporadic," and may complicate any index pregnancy. A lower placental weight was more prevalent in the control group, supporting the concept that pregnancies complicated by PP following IVF can be attributed to initial abnormal location of placentation, rather than an underlying pathological uterine segment of implantation. Nevertheless, IVF and unassisted pregnancies entail similar perinatal outcomes in cases of PP.

The association of placental pathology and neurodevelopmental outcomes in patients with neonatal encephalopathy

BACKGROUND

Studies conflict on how acute versus chronic placental pathology impacts outcomes after neonatal encephalopathy from presumed hypoxic-ischemic encephalopathy (HIE). We examine how outcomes after presumed HIE vary by placental pathology categories.

METHODS

We performed retrospective chart review for neonates with presumed HIE, regardless of severity, focusing on 50 triads for whom placental specimens were available for re-review. Placentas were categorized as having only acute, any chronic, or no lesions. Primary outcomes included in-hospital morbidity/mortality and long-term neurodevelopmental symptoms. Secondary outcomes assessed neonatal MRI and EEG.

RESULTS

Demographics did not differ between groups. Forty-seven neonates were treated with therapeutic hypothermia. Placental acuity category was not associated with primary or secondary outcomes, but clinical and/or histopathological chorioamnionitis was associated with abnormal EEG background and post-neonatal epilepsy (16.7%, n = 3 with chorioamnionitis versus 0%, n = 0 without chorioamnionitis, p = 0.04).

CONCLUSIONS

When grouped by acute, chronic, or absent placental lesions, we observed no association with in-hospital, neurodevelopmental, MRI, or EEG outcomes. When reanalyzed by the presence of chorioamnionitis, we found that chorioamnionitis appeared to be associated with a higher risk of EEG alterations and post-neonatal epilepsy. Despite our limited sample size, our results emphasize the critical role of placental examination for neuroprognostication in presumed HIE.

IMPACT

Neonatal encephalopathy presumed to result from impaired fetal cerebral oxygenation or blood flow is called hypoxic ischemic encephalopathy (HIE). Prior studies link placental pathology to various outcomes after HIE but disagree on the impact of acute versus chronic pathology. Our study determines that neurodevelopmental outcomes, in-hospital outcomes, injury on MRI, and EEG findings in patients with HIE are not differentially associated with acute versus chronic placental pathology. Chorioamnionitis is associated with an increased risk of abnormal EEG patterns and post-neonatal epilepsy. Histopathologic chorioamnionitis without clinical symptoms is common in HIE, emphasizing the crucial role of placental pathology for neuroprognostication.

A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical exposures during pregnancy include several developmental and reproductive disorders. However, considering the tens of thousands of chemicals present on the market, the effects of chemical mixtures on the developing fetus is still likely underestimated. In this critical review, we discuss the potential to apply innovative biomonitoring methods using high-resolution mass spectrometry (HRMS) on placenta to improve the monitoring of chemical exposure during pregnancy. The physiology of the placenta and its relevance as a matrix for monitoring chemical exposures and their effects on fetal health is first outlined. We then identify several key parameters that require further investigations before placenta can be used for large-scale monitoring in a robust manner. Most critical is the need for standardization of placental sampling. Placenta is a highly heterogeneous organ, and knowledge of the intraplacenta variability of chemical composition is required to ensure unbiased and robust interindividual comparisons. Other important variables include the time of collection, the sex of the fetus, and mode of delivery. Finally, we discuss the first applications of HRMS methods on the placenta to decipher the chemical exposome and describe how the use of placenta can complement biofluids collected on the mother or the fetus.

Placental weights of neonates born with symptomatic congenital syphilis

Background

Syphilis during pregnancy remains an important global health concern causing miscarriage, stillbirth, preterm birth and neonatal death. As part of the fetal infection, placental changes occur which may include a heavier placenta than expected.

Methods

A cohort of 50 neonates with symptomatic congenital syphilis has previously been described. This cohort was admitted to Groote Schuur neonatal unit in Cape Town South Africa from 2011 to 2013. For this study, the placental weights of the neonates were analyzed and compared to population based placental centiles.

Results

There was data for 37 placentae. Heavy placentae (>90th centile) occurred in 76% of placentae in the study. All 6 infants with birth weights ≥2,500 g had heavy placentae. There was no correlation between placental centile and death.

Conclusion

Heavy placenta are an important and frequent finding with symptomatic congenital syphilis, especially in the larger neonates.

Fetal death from SARS-CoV-2 mediated acute placental failure

INTRODUCTION

We demonstrate the nonlinear severity of symptoms of SARS-CoV-2 infection in the mother leading to fetal death after acute placental failure.

METHODS

Careful clinical evaluation, real-time RT-PCR molecular microbiologic testing, isolation of a viable virus, and autopsy with histologic results were used to investigate the possible vertical transmission of SARS-CoV-2 infection from mother to fetus.

RESULTS

Histologic changes in the placenta correlate with SARS-CoV-2 infection. Total nucleic acid isolated from vaginal swabs, fresh placental tissue, and deparaffinized tissue showed a high viral load of SARS-CoV-2. Complete genome sequencing confirmed the presence of the SARS-CoV-2 Delta variant.

DISCUSSION

Several methods have been used to confirm SARS-CoV-2-mediated acute placental failure, all of which were conclusive. It should be noted that careful periodic fetal well-being checks are required in women infected with SARS-CoV-2, regardless of the severity of symptoms. Most of the cases described with fetal death occurred in the third trimester.

Placental Findings in Infants Gestational Age < 34 Weeks and Impact on Short-Term Outcomes

AIM

To analyse placental changes in infants' gestational age < 34 weeks and its correlation to short-term respiratory outcomes or death until hospital discharge.

MATERIAL AND METHODS

Information regarding all in-house born preterm infants born before 34 weeks gestation and born from January 2009 until December 2014 were collected and included among others, placental pathology and relevant data on demographics and outcomes of infants.

RESULTS

Placental abnormalities was found in 157/253 (65.05%) cases. Acute placental inflammation was found to be the most common in both groups of premature neonates, followed by maternal vascular underperfusion. Maternal vascular underperfusion was significantly more common in GA ≤ 27 weeks compared to infants GA 28-33 weeks (35.2% vs. 13.7%; p = 0.018). Similarly, chronic placental inflammation was more common in infants GA ≤ 27 weeks compared to infants GA 28-33 weeks (14.3% vs. 3.3%; p = 0.014). Infants with placental pathology had a lower median birth weight (1460g vs. 1754g; p = 0.001, and were of shorter median GA at birth (31 vs. 32; p = 0.001). Infants with any placental disease had higher rates of death until hospital discharge (10.2% vs. 3.1%; p = 0.039) and higher rates of any stage of bronchopulmonary dysplasia (41.4% vs. 26.0%; p = 0.013). There were no significant differences in mechanical ventilation rates, duration of mechanical ventilation and duration of supplemental oxygen therapy.

CONCLUSION

Identifiable placental abnormalities were found in most infants born < 34 weeks gestation. Placental pathology is associated with increased rates of bronchopulmonary dysplasia and death until hospital discharge.

Placental-fetal distribution of carbon particles in a pregnant rabbit model after repeated exposure to diluted diesel engine exhaust

BACKGROUND

Airborne pollution particles have been shown to translocate from the mother's lung to the fetal circulation, but their distribution and internal placental-fetal tissue load remain poorly explored. Here, we investigated the placental-fetal load and distribution of diesel engine exhaust particles during gestation under controlled exposure conditions using a pregnant rabbit model. Pregnant dams were exposed by nose-only inhalation to either clean air (controls) or diluted and filtered diesel engine exhaust (1 mg/m³) for 2 h/day, 5 days/week, from gestational day (GD) 3 to GD27. At GD28, placental and fetal tissues (i.e., heart, kidney, liver, lung and gonads) were collected for biometry and to study the presence of carbon particles (CPs) using white light generation by carbonaceous particles under femtosecond pulsed laser illumination.

RESULTS

CPs were detected in the placenta, fetal heart, kidney, liver, lung and gonads in significantly higher amounts in exposed rabbits compared with controls. Through multiple factor analysis, we were able to discriminate the diesel engine exposed pregnant rabbits from the control group taking all variables related to fetoplacental biometry and CP load into consideration. Our findings did not reveal a sex effect, yet a potential interaction effect might be present between exposure and fetal sex.

CONCLUSIONS

The results confirmed the translocation of maternally inhaled CPs from diesel engine exhaust to the placenta which could be detected in fetal organs during late-stage pregnancy. The exposed can be clearly discriminated from the control group with respect to fetoplacental biometry and CP load. The differential particle load in the fetal organs may contribute to the effects on fetoplacental biometry and to the malprogramming of the fetal phenotype with long-term effects later in life.

Pravastatin for severe preeclampsia with growth restriction: Placental findings and infant follow-up

OBJECTIVE

Preeclampsia (PE) is the major cause of maternal morbidity and mortality and the leading cause of premature delivery worldwide. As well as intrauterine growth restriction (IUGR), PE is associated with pathogenic evidence of placental malperfusion and ischemia. Recent literature has highlighted the potential of pravastatin in the prevention and treatment of these conditions. Aim of this study is to describe perinatal outcomes and placental histopathological findings in a small series of pregnant women with severe PE and IUGR treated with pravastatin on compassionate grounds. Two-year follow up of these babies is provided.

STUDY DESIGN

Between October 2017 and October 2019 in Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, Italy, women with singleton pregnancy between 19.6 and 27.6 gestational weeks, who presented with severe PE and IUGR were counselled for a compassionate treatment with Pravastatin 40 mg a day. Treated women were compared with controls identified with similar data in terms of gestational age at diagnosis, clinical maternal data, Doppler severity findings. Neonates were followed up for two years.

RESULTS

The median time from diagnosis to delivery was 39 days (IQR 20) for women in the pravastatin group and 20 days (IQR 20.5) for controls. Looking to maternal blood exams, in the group of women treated with pravastatin, maximum transaminase, creatinine levels were lower than in controls, where the minimum platelet count was higher. Placenta examination did not reveal any significant differences in placental histopathological findings. No significant differences were observed in the investigated perinatal data, as well as in infant follow-up, although an increased prenatal weight gain was found in treated pregnancies in comparison to controls.

CONCLUSIONS

Our data did not allow us to find significant differences in pregnancy outcome and infant follow-up, as well as in placental histological picture in preeclamptic patients when pravastatin is administered in the late second trimester. However, we suggest its possible role in stabilizing the disease, increasing the prenatal weight gain and prolonging the duration of pregnancy, thus preventing the progression to a more severe maternal disease.

The effects of preconception and early gestation SARS-CoV-2 infection on pregnancy outcomes and placental pathology

OBJECTIVE

To evaluate if peri-pregnancy timing of a PCR+ test for SARS-CoV-2 RNA affects pregnancy outcomes and placental pathology.

METHODS

This is a retrospective cohort study conducted in a tertiary center. Pregnancy outcomes and placental pathology were compiled for women who tested positive for SARS-CoV-2 RNA from a nasopharyngeal swab assessed by RT-PCR. The population comprised four groups that were PCR+ preconception (T₀) or in the 1st (T₁), 2nd (T₂), or 3rd (T₃) trimester of pregnancy. A fifth, control group (T_C) tested PCR- for SARS-CoV-2 before delivery.

RESULTS

Seventy-one pregnancies were studied. The T₀ group exhibited lower gestational ages at delivery, had infants with the lowest birth weights, the highest rate of pregnancy loss before 20 weeks. Features of maternal vascular malperfusion and accelerated villous maturation were prominent findings in the histopathology of placentas from women PCR+ for SARS-CoV-2 RNA, especially in the T₀ and the T₁ groups.

CONCLUSION

Women at highest risk for pregnancy complications are those who test PCR+ for viral RNA preconception or during first trimester of pregnancy.

Case report: Umbilical vessel aneurysm thrombosis and factor V Leiden mutation leading to fetal demise

Complicated pregnancies are nowadays a major public health concern, with possible lethality or sequelae both for the mother and the fetus. Blood coagulation disorders (including antiphospholipid syndrome, factor V Leiden mutation and antithrombin deficiency) and hypertensive gestational disorders are very well-known contributors of complicated pregnancies with poor fetal outcome, such as intrauterine growth retardation (IUGR) and fetal demise. Less commonly, vascular malformations of the placenta can also potentially lead to serious complications such as IUGR and fetal death. These malformations include hypercoiled umbilical cord, umbilical cord knot, umbilical cord varix, umbilical cord arterial or venous aneurysm, and velamentous insertion of the umbilical cord potentially leading to Benckiser's hemorrhage. Here, we report the case of a 29-year-old Gravida 2 Para 0 mother with previous history of stillbirth and smoking, admitted to the obstetrics department for the absence of fetal movement at 38 weeks of amenorrhea (WA). First-trimester and second-trimester routine ultrasounds were otherwise normal. Ultrasound performed at 38 WA revealed a 83 × 66 × 54 mm cystic heterogenous mass at the umbilical cord insertion. After delivery, fetal and placental pathology as well as maternal blood testing were performed. Fetal pathology was otherwise normal, except for diffuse congestion and meconial overload suggesting acute fetal distress. Fetal karyotype was normal (46 XX). Placental pathology revealed an umbilical artery aneurysm (UAA) at the base of the insertion of the umbilical cord, lined with a CD34⁺ CD31⁺ endothelium. After dissection, the aneurysm was filled with hemorrhagic debris, indicating aneurysm thrombosis. Histopathology revealed associated maternal vascular malperfusion (MVM) and increased peri-villous fibrin (IPF). Maternal blood tests revealed heterozygous factor V Leiden mutation, without other associated auto-immune conditions (such as antiphospholipid syndrome). Umbilical artery aneurysms remain extremely rare findings in the placenta, with <20 reported cases. Umbilical artery aneurysms have tendency to be located at the base of the insertion of the placenta, and lead to fetal demise in more than 60% of cases, mainly due to aneurysmal thrombosis, hematoma, possible vascular compression and/or rupture. Umbilical vessel aneurysms can be associated with trisomy 18 or 13. In our case, the association of factor V Leiden mutation, a hypercoagulable state, with UAA could explain massive thrombosis of the aneurysmal lumen and sudden fetal demise. Further consideration of current guidelines for surveillance and management of UAA would allow appropriate planned delivery in maternal care settings.

Normative values of renin and aldosterone in clinically stable preterm neonates

BACKGROUND

There is a paucity of literature on the normative levels of plasma renin concentration (PRC) and serum aldosterone (SA) in premature neonates. This study aims to provide normative data on PRC and SA levels in preterm neonates in the first 2 weeks after birth and explore associations with maternal, perinatal, or postnatal factors.

METHODS

Neonates born at 26- to 34-week gestation were recruited from two neonatal intensive care units in Canada and Australia. The direct renin assay PRC and SA were analyzed on day 1 and days 14-21 after birth to compare across categorical variables and to produce normative values.

RESULTS

A total of 262 subjects were enrolled from the Canadian (29%) and Australian (71%) sites. The mean gestational age was 30 weeks, with a mean birth weight of 1457 g. The normative values of PRC and SA for neonates born between 26 + 0 and 29 + 6 weeks and 30 + 0 and 34 + 0 weeks of gestation were produced for day 1 and day 14-21 after birth. Both PRC and SA increased from day 1 to day 14-21. The more premature neonates reached a higher PRC on days 14-21 after birth but exhibited lower SA levels on day 1 after birth. When comparing gender, birth weight, and maternal risk factor categories, no statistical differences in PRC or SA were found. A small but significant decrease in PRC, but not SA, was noted for neonates with placental pathology.

CONCLUSIONS

This study produced normative values of PRA and SA in clinically stable preterm neonates that can be referenced for use in clinical practice. A higher resolution version of the Graphical abstract is available as Supplementary information.

Placental findings in singleton stillbirths: a case-control study from a tertiary-care center in India

OBJECTIVES

Placental examination in a case of stillbirth can provide insight into causative/associated factors with fetal demise. The aim of this study was to compare placental and umbilical cord pathologies in singleton stillbirth and livebirth placentas, and to find prevalence of various associated maternal and fetal clinical factors.

METHODS

This case-control study was conducted at a tertiary-care center in India over a period of 20 months. About 250 women who delivered stillborn fetus ≥28 weeks' gestation and 250 maternal-age-matched controls were recruited. Sociodemographic and clinical details were noted and placental gross and microscopic examination was done. Placental findings were compared between stillbirth and livebirth (overall), preterm stillbirth and preterm livebirth as well as term stillbirth and term livebirth in six categories - placenta gross, cord gross, membranes gross, maternal vascular malperfusion, fetal vascular malperfusion and inflammatory response. Prevalence of 11 maternal and fetal factors were studied in all categories of placental findings in both livebirth and stillbirth.

RESULTS

Placental findings in all six categories were significantly associated with stillbirths (p<0.05). The placental findings associated with stillbirth with highest odds included placental hypoplasia (OR 9.77, 95% CI 5.46-17.46), necrotizing chorioamnionitis (OR 9.30, 95% CI 1.17-73.96) and avascular villi (OR 8.45, 95% CI 3.53-20.25). More than half of the women with stillbirths had medical disorders (n=130, 52.0%) and the most prevalent was hypertensive disorder (n=45, 18.0%).

CONCLUSIONS

Changes in placenta are associated with development of stillbirth. Therefore, antenatal investigations to identify placental dysfunction should be investigated to determine whether these reduce stillbirth. Also, placental examination in a case of stillbirth can detect/diagnose many maternal/fetal conditions and thereby can help in preventing future stillbirths.

The placental pathology in Coronavirus disease 2019 infected mothers and its impact on pregnancy outcome

Introduction

This study aims at observing placental pathologies in COVID-19 infected women, and analyzing its impact on pregnancy outcome.

Method

This is a descriptive-analytical study done at a tertiary centre of Northern India. All COVID-19 positive pregnant women with gestational age ≥20 weeks, with placental histopathological reporting, were included in this study. A total of 173 COVID-19 pregnant women were included in the study.

Results

Placental abnormalities were noticed in 49·16% of total 179 placentae examined. Maternal vascular malperfusion (27·93%) was the most observed placental pathology followed by villous fibrin deposits (22·90%), fetal vasculopathy (16·75%), and acute inflammation (6·70%). Stillbirths were 22 and NICU admissions were seen in 50 neonates. Abnormal placental abnormalities led to higher stillbirths (p value 0·011) and lower Apgar scores at 1 and 5 min (p-value 0·028; p-value 0·002, respectively). Intervillous fibrin deposits had higher risk associated with lower Apgar score at 1 and 5 min [RR 2·05 (95% CI 1·21–3·48, p-value 0·010) and RR 5·52 (95% CI 2·58–11·81, p-value <0·001), respectively]. RP clot/hemorrhage was also associated with lower Apgar score at 1 and 5 min [RR 2·61 (95% CI 1·52–4·49, p-value 0·002) and RR 3.54 (95% CI 1·66–7·55, p-value 0·001), respectively].

Discussion

Placental abnormalities in COVID-19 infection were associated with significant higher incidence of unexplained stillbirths, and lower Apgar scores. Although, this is the largest descriptive-analytical study done so far, comparative studies are required to draw a clear conclusion regarding the impact of COVID-19 infection on human placenta and its effect on pregnancy outcomes.

Perinatal outcomes and placental histology in small-for-gestational-age pregnancies-A comparison of population-based and universal growth charts

OBJECTIVE

To assess obstetric, perinatal, and placental histologic findings in small-for-gestational-age (SGA) neonates according to different growth charts.

METHODS

A retrospective cohort of singleton deliveries from 2008 to 2019 were divided into SGA neonates according to the local population-based chart, SGA according to universal standard growth charts (but appropriate for gestational age [AGA] according to local charts) and AGA deliveries according to both charts.

RESULTS

A total of 626 local population SGA deliveries, 132 universal SGA and 468 AGA deliveries were compared. The local population SGA group had a significantly higher rate of preterm and cesarean deliveries. An adverse neonatal outcome occurred in 27.2% of the local population SGA group, 9.8% of the universal SGA group and 6.7% of the AGA group (P < 0.001). In the local population SGA group, placental weight was lower, birth weight to placental weight ratio was highest, and the rate of maternal malperfusion lesions was highest-55.4% versus 45.4% in the universal SGA group and 39.1% in the AGA group (P < 0.001). Villitis of unknown etiology was significantly more common and histologic chorioamnionitis was significantly less common in the local population SGA group.

CONCLUSIONS

Our findings support the use of a local population-based growth chart for the diagnosis of fetal growth restriction.

Chronic histiocytic intervillositis: manifestation of placental alloantibody-mediated rejection

BACKGROUND

Chronic histiocytic intervillositis (chronic intervillositis) is defined by a diffuse infiltration of monocytes into the intervillous space, which often leads to poor obstetrical outcomes, including recurrent intrauterine growth restriction, miscarriage, and fetal death. The pathogenesis of chronic intervillositis is still poorly defined, and there is an unmet medical need for improved management.

OBJECTIVE

This study aimed to demonstrate the role of anti-human leukocyte antigen alloantibodies in the pathogenesis of chronic intervillositis through the application of criteria used in solid-organ transplantation for the diagnosis of antibody-mediated rejection.

STUDY DESIGN

A multidisciplinary research study based on thorough immunologic and pathologic investigations was carried out for 2 separate couples who experienced recurrent secondary fetal losses following a first normal pregnancy associated with histologic evidence of chronic intervillositis.

RESULTS

Very high levels of complement-fixing, fetus-specific antibodies targeting mismatched human leukocyte antigen alleles, harbored by the 2 paternal haplotypes, were identified in both cases. Polymorphic human leukocyte antigens were expressed on the surface of trophoblastic villi of the inflamed placenta but not in healthy placental tissue. The binding of alloantibodies to paternal human leukocyte antigens induced dramatic activation of the complement classical pathway in trophoblastic villi, leading to C4d deposition and formation of the terminal complex C5b-9. All requirements for the diagnosis of antibody-mediated placental rejection were fulfilled according to the criteria used in the Banff classification of allograft pathology. In silico analysis was performed using a human leukocyte antigen epitope viewer to reconstitute the human leukocyte antigen sensitization history. Reactivity against a single mismatched epitope present in the first-born healthy child accounted for a broad sensitization to human leukocyte antigens, including those harbored by the 2 paternal haplotypes. This finding explained the high rates of chronic intervillositis recurrence during subsequent pregnancies.

CONCLUSION

This study provides novel mechanistic insights into the pathogenesis of chronic intervillositis and provides new avenues for individualized counseling and therapeutic options.

SARS-CoV-2 Infection in Pregnancy: Clinical Signs, Placental Pathology, and Neonatal Outcome-Implications for Clinical Care

Introduction: The current COVID-19 pandemic has been associated with high rates of mortality and significant morbidity. Both the risk of infection for pregnant women and the risk of vertical transmission have been evaluated, and the presence of the SARS-CoV-2 virus has been demonstrated both in the placenta and in the amniochorionic membranes. However, the actual effects of this pathogen on pregnancy and on placental morphology are still unclear. Objective: To describe histopathologic findings in the placentas of women with SARS-CoV-2 infection during pregnancy and their correlation with clinical signs and perinatal outcome. Methods: Placental tissues from pregnant women with SARS-CoV-2 infection delivering between March 2020 and February 2021 were analyzed. Results: One hundred six placentas from women with SARS-CoV-2 infection during pregnancy who delivered in Fondazione Policlinico A. Gemelli were examined. Most of them were asymptomatic. All neonates had available test results for SARS-CoV-2 and only one resulted positive. Placental tissues mainly showed signs of maternal vascular malperfusion and of placenta injury in terms of syncytial node increase (96.2%), villar agglutination (77.3%), neointimal hyperplasia (76.4%), excessive fibrin deposition (43.3%), and chorangiosis (35.8%). No significant differences in the frequency of the histopathological lesions were observed according to maternal symptoms. Conclusion: Looking to placental tissues from SARS-CoV-2 positive women at the screening performed close to delivery, placental injuries could be detected without any correlation with fetal and neonatal outcomes. We hypothesize that short latency between SARS-CoV-2 infection and delivery is the main reason for these observations.

Neuraxial Techniques for Parturients with Thromboprophylaxis or Thrombocytopenia

Pharmacologic thromboprophylaxis from venous thromboembolism (VTE) and thrombocytopenia in pregnancy results in conditions that may preclude the use of neuraxial anesthesia due to a perceived risk of spinal/epidural hematoma. Spinal epidural hematoma is a recognized complication in patients who are hypocoagulable and may lead patients to undergo general anesthesia for delivery or other procedures, which carries numerous complications in obstetric care. A robust understanding of maternal physiologic changes in coagulation status, review of consensus statements, and safety bundles may help to maximize the use of neuraxial anesthesia in obstetric patients who might otherwise be denied these anesthetic techniques.

Placental weight centiles adjusted for age, parity and fetal sex

INTRODUCTION

The weight of the placenta can be indicative of efficacy in nutrient and oxygen supply. Furthermore, it has been suggested that a measure of the placenta's ability to adequately supply nutrients to the fetus can be found in the relationship between birth weight and placental weight expressed as a ratio. Our aim was to develop age adjusted placenta weight and birth weight to placenta weight ratio reference curves that are stratified by maternal parity and fetal sex.

METHODS

We included singleton, non-anomalous births with a gestational age inclusive of 28 + 0 weeks to 42 + 6 weeks. Excluded were pregnancies of multiplicity, fetuses with congenital abnormalities, stillbirths and pregnancies that had placental complications (ie placenta previa or abruption). Generalised additive model for location, shape and scale (GAMLSS) was used to fit reference curves.

RESULTS

We stratified 97,882 pregnancies by maternal nulliparity status and fetal sex. Extensive assessment model goodness-of-fit showed appropriate modeling and accurate fit to the four parameters of distribution. Our results show accurate model fit of the reference curves to the data. We demonstrated that the influence that parity has on the placenta weight is far greater than that exerted by fetal sex, and that the difference is dependent on gestational age.

DISCUSSION

This is the largest presentation of age and parity adjusted placenta weight and feto-placental weight ratio reference ranges to date. The difference observed between nulliparous and multiparous pregnancies could be explained by biological memory and the remnants of maternal endo-myometrial vascularity after the first pregnancy.

Enhanced elimination of betamethasone in dichorionic twin pregnancies

AIM

No study has evaluated the betamethasone pharmacokinetics in twin pregnancies according to chorionicity. This study aimed to describe and compare the betamethasone pharmacokinetic parameters in singleton and dichorionic (DC) and monochorionic twin pregnancies in the third trimester of pregnancy.

METHODS

Twenty-six pregnant women received 2 intramuscular doses of 6 mg of betamethasone sodium phosphate plus 6 mg betamethasone acetate due to preterm labour. Serial blood samples were collected for 24 hours after the first intramuscular dose of betamethasone esters. Betamethasone plasma concentrations were quantified using a validated liquid chromatography-tandem mass spectrometry analytical method, and the pharmacokinetic parameters were obtained employing a noncompartmental model. Preliminary data on the betamethasone placental transfer are also presented.

RESULTS

The geometric mean (95% confidence interval) of AUC^0-∞ 645.1 (504.3-825.2) vs. 409.8 (311.2-539.6) ng.h/mL and CL/F 17.70 (13.84-22.65) vs. 27.87 (21.17-36.69) were significantly different, respectively, in singleton pregnancies when compared to DC twins.

CONCLUSION

Data from this study suggest that the presence of 2 foetoplacental units may increase the betamethasone metabolism by hepatic CYP3A4 and/or placental 11β-HSD2 enzymes. Pharmacokinetic-pharmacodynamic clinical studies are needed to investigate whether these betamethasone pharmacokinetic changes have clinical repercussions for the newborns and require dose adjustment in DC twin pregnancies.

Association between pregravid liver enzyme levels and gestational diabetes in twin pregnancies: a secondary analysis of national cohort study

Multiple pregnancies are prone to gestational diabetes mellitus (GDM). This study investigated the association between pregravid liver enzyme levels and the development of GDM in a twin pregnancy. Women who had the National Health Screening Examination and delivered their twin babies within one year were enrolled. Pregravid liver enzyme levels were divided into high and low level. Risks for developing GDM by high levels of liver enzymes were analyzed, in subgroups by pregravid obesity or metabolic syndrome. Among the 4348 twin pregnancies, 369 women (8.5%) developed GDM not requiring insulin treatment (GDM - IT), and 119 women (2.7%) developed GDM requiring insulin treatment(GDM + IT). High levels of pregravid GGT and ALT were related to risks of GDM + IT not only in women with obesity or metabolic syndrome (odds ratio[OR] 6.348, 95% confidence interval [CI] 2.579-15.624 and OR 6.879, 95% CI 2.232-21.204, respectively), but also in women without obesity (OR 3.05, 95% CI 1.565-5.946) or without metabolic syndrome (OR 3.338, 95% CI 1.86-5.992), compared to in women with low levels of those. However, there were no significant associations in the pregravid ALT and GGT levels and risks for development of GDM - IT, unrelated to pregravid obesity or metabolic syndrome. Therefore, this study suggests that women with high levels of pregravid GGT and ALT need to recognize their increased risk of GDM + IT, regardless of pregravid obesity or MetS, when they get pregnant twin.

Sudden fetal death with placental mesenchymal dysplasia complicated by placenta previa

Placental mesenchymal dysplasia (PMD) is a rare placental abnormality that is closely related to severe pregnancy complications. A 27-year-old woman with fetal growth restriction and placenta previa was referred to a university hospital at 22 gestational weeks (GW). She was suspected of having a twin pregnancy with a complete or partial hydatidiform mole and coexisting normal live fetus, because two separate placentas, an enlarged one with multiple cystic lesions and a normal one, were shown on ultrasound examinations. At 27 GW, she experienced a sudden intrauterine fetal death (IUFD) after bleeding due to placenta previa, despite confirmation of fetal well-being at 2 h before bleeding. After delivery, histopathological examination confirmed the diagnosis of PMD. This is the first documented case of a woman with PMD and placenta previa who had a sudden IUFD after bleeding. Patients with both PMD and placenta previa should be considered at extremely high risk for IUFD.

Normative placental structure in pregnancy using quantitative Magnetic Resonance Imaging

INTRODUCTION

To characterize normative morphometric, textural and microstructural placental development by applying advanced and quantitative magnetic resonance imaging (qMRI) techniques to the in-vivo placenta.

METHODS

We enrolled 195 women with uncomplicated, healthy singleton pregnancies in a prospective observational study. Women underwent MRI between 16- and 40-weeks' gestation. Morphometric and textural metrics of placental growth were calculated from T2-weighted (T2W) images, while measures of microstructural development were calculated from diffusion-weighted images (DWI). Normative tables and reference curves were constructed for each measured index across gestation and according to fetal sex.

RESULTS

Data from 269 MRI studies from 169 pregnant women were included in the analyses. During the study period, placentas undergo significant increases in morphometric measures of volume, thickness, and elongation. Placental texture reveals increasing variability with advancing gestation as measured by grey level non uniformity, run length non uniformity and long run high grey level emphasis. Placental microstructure did not vary with gestational age. Placental elongation was the only metric that differed significantly between male and female fetuses.

DISCUSSION

We report quantitative metrics of placental morphometry, texture and microstructure in a large cohort of healthy controls during the second and third trimesters of pregnancy. These measures can serve as normative references of in-vivo placental development to better understand placental function in high-risk conditions and allow for the early detection of placental mal-development.

Placenta histopathology in SARS-CoV-2 infection: analysis of a consecutive series and comparison with control cohorts

Infection by SARS-CoV-2 has been shown to involve a wide range of organs and tissues, leading to a kaleidoscope of clinical conditions. Within this spectrum, an involvement of the fetal-maternal unit could be expected, but, so far, the histopathological evaluation of placentas delivered by women with SARS-CoV-2 infection did not show distinct hallmarks. A consecutive series of 11 placentas, delivered by 10 women with COVID-19 admitted to our Obstetrics and Gynecology clinic have been investigated and compared to a control cohort of 58 pre-COVID-19 placentas and 28 placentas delivered by women who had a previous cesarean section. Four out of eleven placentas showed changes consistent with chronic villitis/villitis of unknown etiology (VUE), while in one case, chronic histiocytic intervillositis was diagnosed. Thrombo-hemorrhagic alterations were observed in a subset of cases. Compared to the control cohort, chronic villitis/VUE (p < 0.001), chronic deciduitis (p = 0.023), microvascular thrombosis (p = 0.003), presence of infarction areas (p = 0.047) and of accelerated villous maturation (p = 0.005) showed higher frequencies in placentas delivered by women with COVID-19. Chronic villitis/VUE (p = 0.003) and accelerated villous maturation (p = 0.019) remained statistically significant by restricting the analysis to placentas delivered after a previous cesarean section. The observed differences in terms of pathological findings could be consistent with SARS-CoV-2 pathogenesis, but just a subset of alterations remained statistically significant after adjusting for a previous cesarean section. A careful consideration of potential confounders is warranted in future studies exploring the relationship between COVID-19 and pregnancy.

Physiology of intra-abdominal volume during pregnancy

A total of 580 pregnant and 50 puerperal women were included in this cross-sectional study to assess the physiological changes that allow women to adapt to a chronic increase in intra-abdominal pressure during pregnancy. The volume of the uterus, intra-abdominal volume (IAV), visceral and subcutaneous fat was calculated. During pregnancy, the IAV increases up to 1.5 times. Changes in IAV until 24 weeks present a linear relationship (5.2%); thereafter, changes become exponential and, at 40 weeks, IAV increases by 61%. This fact is exclusively related to the progressive growth of the foetus and to the increase in uterine size. At term, the IAV reserve is exhausted, becoming equal the anteroposterior and transverse diameters of the abdomen.In conclusion, the adaptive capabilities of IAV related to the foetal growth are limited by the IAV reserve. The reserve capacity of the IAV and tensile properties of the abdominal wall can be estimated by the dynamics of the anteroposterior and transverse abdominal diameters.IMPACT STATEMENTWhat is already known on this subject? A causal relationship between intra-abdominal hypertension and the development of adverse obstetric and perinatal outcomes has been suggested. Nevertheless, the role of this condition as a leading cause of systemic dysfunction during pregnancy remains unrecognised and underestimated.What do the results of this study add? This study assesses the dynamics of IAV in uncomplicated singleton pregnancies.What are the implications of these findings for clinical practice and/or further research? The study of abdominal pressure indicators such as intra-abdominal volume and compliance will help to a better understand the aetiology, pathophysiology, prognosis and treatment strategies for pregnant women with intra-abdominal hypertension.

Chronic Intervillositis of Unknown Etiology: Development of a Grading and Scoring System That Is Strongly Associated With Poor Perinatal Outcomes

Chronic intervillositis of unknown etiology (CIUE) is a rare placental disease characterized by intervillous infiltration of maternal macrophages and associated with poor pregnancy outcomes and a high risk of recurrence in subsequent pregnancies. Its pathophysiology remains unclear and prognostic factors have not yet been established. In addition, clear relationships between the histologic extent of lesions and the severity of perinatal outcomes have not been demonstrated. Our objectives were to validate a CIUE classification system based on the gradation of macrophagic infiltration of the intervillous space, and to attempt to correlate these results with perinatal outcomes. For this multicenter retrospective study, 3 pathologists reviewed all cases diagnosed with "intervillositis" between 1997 and 2018. Confirmed CIUE cases were semiquantitatively graded based on the percentage of macrophagic infiltrate in the intervillous space: grade 1 (5% to 10%), grade 2 (10% to 50%), and grade 3 (>50%). Multiple pregnancies and pregnancies with medical follow-up completed outside of the study centers were excluded. In total, 122 cases of CIUE in 102 patients were included in the study. Microscopic classification based on one criterion was easy to perform, and interobserver correlation was good. Grade 3 infiltration was strongly associated with poor perinatal outcomes and fetal growth restriction (P<0.0001). After delivery, only 16.1% of newborns from the grade 3 CIUE group were alive, compared with 59% from the grade 2 and 86.5% from the grade 1 group (P=0.0002). Recurrence risk was associated with CIUE gradation of the index case (P=0.004), with 95% of recurrent CIUE cases being from patients with grades 2 and 3 CIUE. In this study, conducted with the largest CIUE cohort to date, a classification based only on the degree of macrophagic infiltration of the intervillous space was validated, and this classification was shown to be strongly associated with poor perinatal outcomes and risk of recurrence.

Factors contributing to late stillbirth among women with pregnancy hypertension in a developing country

OBJECTIVE

To investigate the factors associated with late stillbirth among women with hypertensive disorders of pregnancy (HDP).

MATERIAL AND METHODS

The clinical details of women with HDP having late stillbirth were compared with controls having livebirth.

RESULTS

Total 208 cases and 288 controls were included in the study. Inadequate antenatal visits (p < 0.001, OR-5.92). birth weight < 2000 gms (p < 0.001, OR 10.3) and BW/PW ratio > 8 contributed significantly (p = 0.0001, OR-5.6) to stillbirth.

CONCLUSION

Poor antenatal care, birth weight below 2000gms and high BW/PW ratio was associated with a higher risk of stillbirth.

Placental-related disorders of pregnancy and IVF: does placental histological examination explain the excess risk?

RESEARCH QUESTION

What are the clinical characteristics of pregnancies complicated by fetal growth restriction (FGR) and preeclampsia in patients who have undergone IVF, and what is the correlation between these complications and histopathological placental findings in such pregnancies.

DESIGN

A retrospective cohort of patients who had delivered their babies at our institution who had been diagnosed with preeclampsia, whose babies had been diagnosed with FGR, or both. Deliveries in which the placenta was sent for histopathological examination were included. Computerized files and pathological reports were reviewed, and maternal, obstetric, neonatal outcomes and placental histopathological reports were compared between pregnancies conceived by IVF and controls. Placental lesions were classified according to the Amsterdam criteria.

RESULTS

Between December 2008 and December 2018, the placentas of 1114 singleton babies who had received a diagnosis of FGR, whose mothers had received a diagnosis of preeclampisa, or both, were examined. A total of 105 patients conceived with IVF and 1009 were conceived spontaneously. The IVF group was older, of lower parity and had a higher rate of diabetes and chronic hypertension. Deliveries occurred at an earlier gestational age, although birth weight was not significantly different between the groups. The rate of neonatal adverse composite outcome among IVF deliveries was significantly lower (59.0% versus 76.7%; P < 0.001). On placental examination, placental weight, maternal and fetal vascular malperfusion lesions were similar between the groups, whereas villitis of unknown etiology was significantly more common among the IVF group (16.2% versus 8.3%; P = 0.007).

CONCLUSION

Neonatal outcome is relatively favourable in IVF patients with placental-related diseases. Placental chronic villitis is more common in IVF patients, pointing to an additive immunological cause.

Placental histopathology in sickle cell disease: A descriptive and hypothesis-generating study

INTRODUCTION

Abnormal placental development is a unifying factor amongst many adverse pregnancy outcomes (APOs) in Sickle Cell Disease (SCD). Our aim was to describe placental histopathologic findings in women with SCD and their relationship with APOs, and to explore the association between antenatal sonographic findings and placental pathology.

METHODS

Retrospective single-centre case series of all pregnant women with SCD (January 2000-December 2017), pregnancy beyond 20 weeks' gestation, and available placenta histopathology. APOs included intrauterine fetal death, early neonatal death, preterm birth, small for gestational age, and hypertensive disorders of pregnancy. Review of images for mid-pregnancy ultrasound and one proximal to delivery was completed, blinded to clinical outcomes and histopathology results. Gross and histopathologic findings were reviewed and characterized per published classification.

RESULTS

Of 72 placentas, abnormalities were present in 69%, with Maternal Vascular Malperfusion (MVM) noted in 40%. APOs were encountered in 61% overall and in 79% of those with MVM. Neither SCD genotype nor severe maternal anemia had an influence on histopathologic placental features. Presence of high-resistance uterine artery waveforms at mid-trimester ultrasound was strongly associated with APOs and with abnormal findings on placental histopathology, most notably MVM. MVM was strongly associated with small for gestational age infants, preterm birth, and stillbirth.

DISCUSSION

MVM is the predominant lesion in placentas of women with SCD and is strongly associated with APOs. Mid-trimester ultrasound can identify a subset of women at risk. Future research into advanced imaging modalities to aid in antenatal diagnosis alongside investigations of potentially beneficial therapies is needed.

Exploring in vivo placental microstructure in healthy and growth-restricted pregnancies through diffusion-weighted magnetic resonance imaging

INTRODUCTION

Gross and microstructural changes in placental development can influence placental function and adversely impact fetal growth and well-being; however, there is a paucity of invivo tools available to reliably interrogate in vivo placental microstructural development. The objective of this study is to characterize invivo placental microstructural diffusion and perfusion in healthy and growth-restricted pregnancies (FGR) using non-invasive diffusion-weighted imaging (DWI).

METHODS

We prospectively enrolled healthy pregnant women and women whose pregnancies were complicated by FGR. Each woman underwent DWI-MRI between 18 and 40 weeks gestation. Placental measures of small (D) and large (D*) scale diffusion and perfusion (f) were estimated using the intra-voxel incoherent motion (IVIM) model.

RESULTS

We studied 137 pregnant women (101 healthy; 36 FGR). D and D* are increased in late-onset FGR, and the placental perfusion fraction, f, is decreased (p < 0.05 for all).

DISCUSSION

Placental DWI revealed microstructural alterations of the invivo placenta in FGR, particularly in late-onset FGR. Early and reliable identification of placental pathology in vivo may better guide future interventions.

The effect of maternal obstructive sleep apnea on the placenta

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) during pregnancy has been associated with adverse maternal outcomes. However, the effect of maternal OSA on fetal growth is less clear. The placenta is a critical organ for fetal growth and development and the principal determinant of birthweight. We aimed to investigate the effect of maternal OSA on placental growth and function.

METHODS

Placentas of women recruited to a prospective longitudinal study were consecutively obtained immediately after delivery. Each placenta was measured for length, width, and thickness. Total RNA was isolated for gene expression analysis of VEGF, VEGF receptor, PIGF, and leptin. Histological and morphometric evaluations of the placenta were performed.

RESULTS

A total of 53 placentas were investigated. Ten women (19%) had OSA, and the weight of their placentas was significantly higher compared with the placentas of the controls (526.1 ± 83.9 vs. 425.7 ± 95.5 g, p = 0.004). There was a significant positive correlation between placental weight and the log apnea-hypopnea index even after controlling for maternal body mass index (BMI; r = 0.31, p = 0.04). The birthweight/placental weight ratio was significantly lower in women with OSA compared with controls (p = 0.03). Placental weight and newborn triceps adiposity thickness correlated positively after controlling for maternal BMI (r = 0.29, p = 0.04). Leptin expression was 1.8-fold higher in placentas of women with OSA compared with controls (p = 0.02). No histological differences were found between the groups.

CONCLUSIONS

Maternal OSA is associated with increased placental weight that correlated with OSA severity and neonatal adiposity independently of maternal BMI. Placental leptin overexpression may mediate/underlie the above findings.Trial Registration: Clinical Trials NCT00931099.

Normally Grown Non-dysmorphic Stillbirth Post 38 Weeks Gestation and Reduced Fetal Movements: A Matter of Reserve? A Retrospective Study

This study investigates the relationship between placental weight relative to birthweight and risk of stillbirth in non-dysmorphic fetuses ≥ 38 weeks gestation with no evidence of intrauterine growth restriction. This is a retrospective study of stillbirths who underwent post-mortem between 1st Jan 2011 and 31st Dec 2018 in South East Scotland (n = 55). The control group (n = 74) was matched for gestation, age of mother and maternal BMI. There was a significant difference (p = 0.0117) in the mean ratio of birth weight to placental weight (BW:PW) between the stillbirth group (8.17) and control group (7.33). Cases of stillbirths where the mother had reported reduced fetal movements (RFM) had a higher BW:PW compared to controls (p = 0.024). Within the RFM stillbirth group, 5/6 (83%) cases showed significant changes of maternal vascular malperfusion (MVM) and/or fetal vascular malperfusion (FVM); whilst within the RFM control group, 5/15 (33%) cases showed significant changes of MVM and/or FVM. There is a significantly higher BW:PW within the stillbirth group than within the control group, both groups show changes of MVM and/or FVM and our supposition is that these changes have a greater impact on placental reserve when the birthweight is high relative to placental weight. Reduced fetal movements may indicate diminished placental reserve. We propose that the ability to predict a high BW:PW within pregnancies where the mothers report RFM may help to prevent late stillbirth in non-IUGR infants.

Placental weights from normal deliveries in Ireland

BACKGROUND

The weight of the delivered placenta gives a useful representation of placental function in utero. In the absence of Irish data, many pathologists rely on data from other populations, many of which are now 15 to 30 years old. The development of a population-specific nomogram would aid in the examination of placentas after delivery, allowing pathologists and medical scientists to more easily distinguish between placental physiological changes and pathology.

AIMS

To record placental weights among women having a singleton delivery in Dublin and to establish median placental weights for each gestational age after 37 weeks.

METHODS

Prospective cohort study in a Tertiary level University Hospital. All singleton pregnancies were included; stillbirths, multiple gestations, and cases with obstetric complications involving the placenta were excluded. The placentas were weighed both untrimmed and trimmed with standard scales. Demographic features including birth weight and maternal parity were also recorded.

RESULTS

Four hundred thirty placentas were weighed over a 6-week period. A median term placental weight based on gestational age was established, with a range from the tenth to ninetieth centiles.

CONCLUSION

The weight of the placenta is one of several measurements that are easy to acquire, and when recorded in a systematic fashion, provide information not just on an individual, but also on a population basis. Birth weights have increased over the last century, and this study provides national data helping distinction between placental physiology and pathology.

Maternal vascular malperfusion in spontaneous preterm birth placentas related to clinical outcome of subsequent pregnancy

INTRODUCTION

Spontaneous preterm birth (SPTB) has several causes and its pathophysiology remains unclear. In a significant proportion of SPTB, placental histology shows signs of maternal vascular malperfusion (MVM); commonly associated with hypertensive disorders of pregnancy (HD), fetal growth restriction (FGR) and placental abruption, together referred to as clinical ischemic placental diseases (IPD). We hypothesized that women with SPTB and placental MVM are at elevated risk for IPD in a subsequent pregnancy.

METHODS

We included women with SPTB in our cohort and followed the subsequent ongoing pregnancy (n = 110). Histological placental characteristics in the index were reported according to new international guidelines, and related to the clinical outcome of the subsequent pregnancy.

RESULTS

In the SPTB placentas, we observed MVM in 61.8% (n = 68). In the subsequent pregnancies in 19.1% (n = 21) at least one clinical sign of IPD was present (HD (12.7%), FGR (5.5%) or placental abruption (0.9%)). There was no significant difference in the prevalence of clinical IPD or recurrence of SPTB in the subsequent pregnancy between women with and without placental MVM in the index pregnancy, although our study was not powered to detect small differences.

DISCUSSION

Women with a history of SPTB have an elevated risk of IPD in the subsequent pregnancy. MVM is present in a large proportion of SPTB placentas. The presence of placental MVM in the index pregnancy does not predict clinical IPD or recurrent SPTB in a subsequent pregnancy.

A new customised placental weight standard redefines the relationship between maternal obesity and extremes of placental size and is more closely associated with pregnancy complications than an existing population standard

Placental weight is a valuable indicator of its function, predicting both pregnancy outcome and lifelong health. Population-based centile charts of weight-for-gestational-age and parity are useful for identifying extremes of placental weight but fail to consider maternal size. To address this deficit, a multiple regression model was fitted to derive coefficients for predicting normal placental weight using records from healthy pregnancies of nulliparous/multiparous women of differing height and weight (n = 107,170 deliveries, 37-43 weeks gestation). The difference between actual and predicted placental weight generated a z-score/individual centile for the entire cohort including women with pregnancy complications (n = 121,591). The association between maternal BMI and placental weight extremes defined by the new customised versus population-based standard was investigated by logistic regression, as was the association between low placental weight and pregnancy complications. Underweight women had a greater risk of low placental weight [<10thcentile, OR 1.84 (95% CI 1.66, 2.05)] and obese women had a greater risk of high placental weight [>90th centile, OR 1.98 (95% CI 1.88, 2.10)] using a population standard. After customisation, the risk of high placental weight in obese/morbidly obese women was attenuated [OR 1.17 (95% CI 1.09, 1.25)]/no longer significant, while their risk of low placental weight was 59%-129% higher (P < 0.001). The customised placental weight standard was more closely associated with stillbirth, hypertensive disease, placental abruption and neonatal death than the population standard. Our customised placental weight standard reveals higher risk of relative placental growth restriction leading to lower than expected birthweights in obese women, and a stronger association between low placental weight and pregnancy complications generally. Further, it provides an alternative tool for defining placental weight extremes with implications for the placental programming of chronic disease.

The volume of villi with γ-sm-actin positive perivascular cells correlates with placental weight and thickness

INTRODUCTION

The classification of histologically stained villous cross sections in villous types (terminal, intermediate and stem villi) by stromal peculiarities is known to be observer predicated. Therefore, quantitative histology of villous trees has not become a routine endpoint of studies on the role of the placenta in prenatal programming, as opposed to the gross placental parameters weight and thickness. The classification of villous cross sections in central (stem) and peripheral (terminal) parts based on the presence or absence, respectively, of immunohistochemical detection of myofibroblasts in perivascular position is less observer dependent. We hypothesized that it will, possibly, identify microscopic correlates of placental weight and thickness within the villous tree.

METHODS

50 placentas from clinically normal pregnancies were processed for the present study. Thin villous cross sections, obtained in a systematic random manner, were stained immunohistochemically to detect γ-smooth muscle (sm) actin and to classify them subsequently as part of central or peripheral villous tree. The volume fractions of histological structures visible in villous cross sections (stroma, lumen, endothelium and syncytium) were estimated by design-based stereology.

RESULTS

The present study reveals a significant correlation of placental weight and thickness with the volume estimate of stroma that have myofibroblasts in perivascular position.

DISCUSSION

The positive linear correlation between the volume of central parts of villous trees and the placental weight and thickness is new. Surprisingly, the volume of more peripheral parts of villous trees, which is the main site of materno-fetal exchange does not correlate with placental weight and thickness.

Research platform for children with arthrogryposis multiplex congenita: Findings from the pilot registry

A pediatric registry for arthrogryposis multiplex congenita (AMC) proposes to advance research by providing the platform to inform the distribution, etiology, and natural history of AMC. The registry was piloted on 40 families of children (mean = 8.25 years, 48% males) presenting with AMC across two hospitals in North America. Data on the child's demographic and newborn variables, mothers' and fathers' demographic variables, lifestyle habits, and medical history were collected using a telephone interview with the primary caregiver and review of medical charts. Mean gestational age was 38 weeks, 97% of children presented with lower extremity deformities, and 74% of neonatal interventions targeted the lower extremity. Newborns spent an average of 14 days in the hospital (range 2-56 days) mostly for diagnostic workup and feeding difficulties. Half (49%) of the sample had internal organ involvement. Genetic testing was done on 48% of the children, including chromosome studies, single gene, whole-exome/genome sequencing, and/or microarray studies. Genetic findings were inconclusive in most. Two-thirds of mothers (67%) reported inconsistently feeling fetal movements. This pilot study contributed to the refinement of participant selection, identification of data source, expansion of data sets, and areas for future exploration prior to the implementation of a multisite AMC pediatric registry.

Assessment of placental metal levels in a South African cohort

The placenta plays an important role in mediating the effect of maternal metal exposure on fetal development, acting as both barrier and transporter. Term-placenta metal levels serve as an informative snapshot of maternal/fetal exposure during pregnancy and could be used to predict offspring short- and long-term health outcomes. Here, we measured term-placenta metal levels of 11 metals in 42 placentas from the Soweto First 1000 days cohort (S1000, Soweto-Johannesburg, SA). We compared these placental metal concentrations with previously reported global cohort measurements to determine whether this cohort is at increased risk of exposure. Placental metals were tested for correlations to understand potential interactions between metals. Since these samples are from a birth cohort study, we also performed exploratory analyses to determine whether metal levels were associated with placenta and birth outcomes. Most S1000 placental metal levels were similar to other cohorts; however, cadmium (Cd) levels up to 50-fold lower, and essential elements nickel (Ni) and chromium (Cr) level up to 6- and 16-fold lower, respectively. Cd, Se, and Ni were associated with placenta and birth outcomes. Studies are ongoing to examine underlying mechanisms and how these developmental differences affect long-term health.

The Difference Between Unfixed and Postfixation Placental Weight

OBJECTIVES

Reference values for placental weights correlated with gestational age are used in surgical pathology. Most reference values were established for fresh placentas. Some laboratories routinely fix all placentas, bringing into question the accuracy of the reference weight values. We wanted to determine the impact of fixation on placental weight.

METHODS

One hundred placentas from uncomplicated pregnancies were weighed in the fresh state, after removal of the cord and membranes. After fixation in formalin for 1 day and 5 days, the placentas were reweighed. The change in weight for each placenta was analyzed by a two-tailed paired t test.

RESULTS

Statistically, a small but significant gain in weight occurred after 24 hours (3.7%, P << .001), and there was no significant change identified in the additional 4 days (P = .51). Nine placentas lost weight with fixation; the weight of four was unchanged.

CONCLUSIONS

We consider formalin fixation to add a statistically significant but clinically negligible amount of weight to the placenta.

Premature placental aging in term small-for-gestational-age and growth-restricted fetuses

OBJECTIVE

To perform a comprehensive assessment of the placental aging process in small term fetuses classified as being small-for-gestational age (SGA) or having fetal growth restriction (FGR) through analysis of senescence and apoptosis markers.

METHODS

This was a prospective nested case-control study of singleton pregnancies delivered at term, including 21 control pregnancies with normally grown fetuses and 36 with a small fetus classified as SGA (birth weight between the 3^rd and 9^th percentiles and normal fetoplacental Doppler; n = 18) or FGR (birth weight < 3^rd percentile and/or abnormal cerebroplacental ratio and/or uterine artery Doppler; n = 18). Telomerase activity, telomere length (quantified by comparing the amount of amplification product for the telomere sequence (T) to that of a single copy of the gene 36B4 (S)) and RNA expression of senescence (Sirtuins 1, 3 and 6) and apoptosis (p53, p21, BAX and Caspases 3 and 9) markers (analyzed using the 2^-ΔΔCt method) were determined in placental samples collected at birth and compared between the three groups.

RESULTS

Compared to pregnancies with a normally grown fetus, both SGA and FGR pregnancies presented signs of accelerated placental aging, including lower telomerase activity (mean ± SD, 12.8 ± 6.6% in controls vs 7.98 ± 4.2% in SGA vs 7.79 ± 4.6% in FGR; P = 0.008), shorter telomeres (mean ± SD T/S ratio, 1.20 ± 0.6 in controls vs 1.08 ± 0.9 in SGA vs 0.66 ± 0.5 in FGR; P = 0.047) and reduced Sirtuin-1 RNA expression (mean ± SD 2^-ΔΔCt , 1.55 ± 0.8 in controls vs 0.91 ± 0.8 in SGA vs 0.63 ± 0.5 in FGR; P = 0.001) together with increased p53 RNA expression (median (interquartile range) 2^-ΔΔCt , 1.07 (0.3-3.3) in controls vs 5.39 (0.6-15) in SGA vs 3.75 (0.9-7.8) in FGR; P = 0.040). FGR cases presented signs of apoptosis, with increased Caspase-3 RNA levels (median (interquartile range) 2^-ΔΔCt , 0.94 (0.7-1.7) in controls vs 3.98 (0.9-31) in FGR; P = 0.031) and Caspase-9 RNA levels (median (interquartile range) 2^-ΔΔCt , 1.21 (0.6-4.0) in controls vs 3.87 (1.5-9.0) in FGR; P = 0.037) compared with controls. In addition, Sirtuin-1 RNA expression, telomerase activity, telomere length and Caspase-3 activity showed significant linear trends across groups as severity of the condition increased.

CONCLUSIONS

Accelerated placental aging was observed in both clinical forms of late-onset fetal smallness (SGA and FGR), supporting a common pathophysiology and challenging the concept of SGA fetuses being constitutionally small. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Pathophysiological changes associated with sleep disordered breathing and supine sleep position in pregnancy

Sleep is a complex and active physiological process that if disrupted, can result in adverse outcomes both within and outside of pregnancy. Sleep disordered breathing (SDB) occurs in 10-32% of pregnancies. Substantial physiological changes occur during pregnancy that impact on maternal sleep, which typically deteriorates with advancing gestation. Pregnancy challenges maternal homeostatic regulation of many systems which effect maternal sleep, including the respiratory, cardiovascular, endocrine, and immune systems. SDB can result from varying degrees of airway compromise and potentially cause systemic hypoxia. The hypoxia may be acute, intermittent or chronic in nature with complications dependant on the duration and the gestation at which the insult occurs. It is unlikely that this effect is mediated by a singular mechanistic pathway but results from a complex cascade of events across multiple maternal organ systems. Regardless of the etiology, both SDB and supine sleep position are associated with a variety of obstetric and perinatal complications including, pre-eclampsia/eclampsia, gestational diabetes mellitus, cardiomyopathy, heart failure, fetal growth restriction, poor neonatal condition at birth, stillbirth and neuro-psychiatric problems in offspring. Both maternal sleep position and sleep disordered breathing are potentially modifiable or treatable factors that if addressed have the potential to improve maternal and fetal outcomes. This narrative review summarizes the maternal and placental pathophysiological aberrations associated with sleep disordered breathing and supine sleep position in pregnancy.