Altered fetal growth, placental abnormalities, and stillbirth

Multidisciplinary Workup for Stillbirth at a Tertiary-Care Hospital in Northeast Mexico: Findings, Challenges and Perspectives

OBJECTIVES

Stillbirth is an important health problem, and in Mexico, only half of the stillbirths have an explainable cause. The aim of this study was to implement a multidisciplinary workup to identify the etiology and potential risk factors for stillbirth at the Hospital Universitario "Dr. José Eleuterio González".

METHODS

This is a prospective, descriptive, observational study that included stillbirths from the Obstetrics Service from October 1st, 2019 to May 25, 2020. Evaluation strategies included a complete maternal medical history, physical examination of the fetus, and a photographic medical record. For every stillbirth either a prenatal ultrasound, a postnatal x-ray, or a fetal autopsy, were needed. Multiplex Ligation Probe Amplification (MLPA) was performed with an umbilical cord sample.

RESULTS

Thirty-three stillbirths were reported; 21 were included in the analysis. Eleven women (52.3%) had known risk factors for stillbirth, mainly elevated body mass index and diabetes. On physical examination, external birth defects were found in 8 fetuses (38%). X-ray was performed in 14 cases (66%), alterations were detected as a probable etiologic cause just in one. All cases underwent MLPA, which were reported negative. Three cases had criteria for autopsy. Findings were inconclusive to determine etiology.

CONCLUSIONS

The best tools for evaluation of stillbirth were the elaboration of clinical history, physical examination, and prenatal ultrasound. Diabetes and obesity were the most frequent risk factors found in our population. These factors are preventable by implementing strategies that lead to better prenatal care.

Prevalence and risk of stillbirth according to biologic vulnerability phenotypes in the municipality of São Paulo, Brazil: A population-based cohort study

OBJECTIVE

To estimate the prevalence and risk of stillbirths by biologic vulnerability phenotypes in a cohort of pregnant women in the municipality of São Paulo, Brazil, 2017-2019.

METHODS

Retrospective population-based cohort study. Fetuses were assessed as small for gestational age (SGA), large for gestational age (LGA), adequate for gestational age (AGA), preterm (PT) as less than 37 weeks of gestation, non-PT (NPT) as 37 weeks of gestation or more, low birth weight (LBW) as less than 2500 g, and non-LBW (NLBW) as 2500 g or more. Relative risks (RR) with robust variance were estimated using Poisson regression.

RESULTS

In all 442 782 pregnancies, including 2321 (0.5%) stillbirths, were included. About 85% (n = 1983) of stillbirths had at least one characteristic of vulnerability, compared with 21% (n = 92524) of live births. Fetuses with all three markers of vulnerability had the highest adjusted RR of stillbirth-SGA + LBW + PT (RR 155.00; 95% confidence interval [CI] 136.29-176.30) and LGA + LBW + PT (RR 262.04; 95% CI 206.10-333.16) when compared with AGA + NLBW + NPT.

CONCLUSION

Our findings show that the simultaneous presence of prematurity, low birth weight, and abnormal intrauterine growth presented a higher risk of stillbirths. To accelerate progress towards reducing preventable stillbirths, one must identify the circumstances of greatest biologic vulnerability.

Autopsy-Based Growth Charts May under-Detect Fetal Growth Restriction at Autopsy

Background: Accurate identification of fetal growth restriction in fetal autopsy is critical for assessing causes of death. We examined the impact of using a chart derived from ultrasound measurements of healthy fetuses (World Health Organization fetal growth chart) versus a chart commonly used by pathologists (Archie et al.) derived from fetal autopsy-based populations in diagnosing small-for-gestational-age (SGA) birth in perinatal deaths. Study Design: We examined perinatal deaths that underwent autopsy at BC Women's Hospital, 2015-2021. Weight centiles were assigned using the ultrasound-based fetal growth chart for birthweight and autopsy-based growth chart for autopsy weight. Results: Among 352 fetuses, 30% were SGA based on the ultrasound-based fetal growth chart versus 17% using the autopsy-based growth chart (p < 0.001). Weight centiles were lower when using the ultrasound-based versus autopsy-based growth chart (median difference of 9 centiles [IQR 2, 20]). Conclusions: Autopsy-based growth charts may under-classify SGA status compared to ultrasound-based fetal growth charts.

Modeling Normal Mouse Uterine Contraction and Placental Perfusion with Non-invasive Longitudinal Dynamic Contrast Enhancement MRI

The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities. Non-invasive imaging that can longitudinally probe murine placental health in vivo are critical to understanding placental development throughout pregnancy. We developed advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development. We developed a dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) pipeline combined with advanced image process methods to model uterine contraction and placental perfusion dynamics. Our novel imaging pipeline uses subcutaneous administration of gadolinium for steepest-slope based perfusion evaluation. This enables non-invasive longitudinal monitoring. Additionally, we advance the placental perfusion chamber paradigm with a novel physiologically-based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and continuing remodeling throughout gestation. Lastly, using optic flow to quantify placental motions arisen from uterine contractions in conjunction with time-frequency analysis, we demonstrated that the placenta exhibited asymmetric contractile motion.

Placental inflammation and pregnancy outcomes: A prospective, observational study in South Asia: The PURPOSe study

OBJECTIVE

To examine inflammatory lesions in placentas of stillbirths, preterm neonatal deaths and term controls in India and Pakistan.

DESIGN

Prospective, observational study.

SETTING

Three hospitals in India and a large maternity hospital in Pakistan.

POPULATION

The enrolled participants with placentas available for histology evaluation included stillbirths (n = 814), preterm live births who died within 28 days of birth (n = 618) and term live birth controls (n = 201). From this same population, polymerase chain reaction (PCR) analysis for pathogens was performed on 809 stillbirth placentas, 614 neonatal death placentas and the placentas of 201 term controls. Placentas from preterm infants who lived beyond day 28 (n = 1432) were only available from India.

METHODS

A prospective observational study of placental inflammatory lesions defined by the Amsterdam criteria and on the same placentas, multiplex PCR evaluation for 75 pathogens using TaqMan Array Cards.

MAIN OUTCOME MEASURES

Any placental inflammatory lesions, including chorioamnionitis, funisitis, villitis and intervillitis and their association with various pathogens.

RESULTS

In the Indian liveborn preterm infants, placental inflammation of any kind was present in 26.2% of those who died versus 16.6% of those who lived (p = 0.0002). Chorioamnionitis was present in 25.8% of those who died versus 16.3% of those who lived (p = 0.0002) and funisitis was present in 4.1% of those who died versus 1.5% of those who lived, (p = 0.005). Across all three sites, in the placentas of the 201 term controls, 18.9% had any inflammation, 16.9% had chorioamnionitis, 5.5% had funisitis, 0.5% had intervillitis and none had villitis. Overall, for stillbirths, any inflammation was observed in 30.2%, chorioamnionitis in 26.9%, funisitis in 5.7%, intervillitis in 6.0% and villitis in 2.2%. For the neonatal deaths, any inflammation was present in 24.9%, chorioamnionitis in 23.3%, funisitis in 8.1%, intervillitis in 1.9% and villitis in 0.5%. Compared with the placentas of term controls, in neonatal deaths, only chorioamnionitis was significantly increased (23.3% versus 16.9%, p = 0.05). Among stillbirths, the rates of any inflammation, chorioamnionitis, intervillitis and villitis were similar across the birthweight groups. However, funisitis was more common in the placentas of stillborn fetuses weighing 2500 g or more (13.8%) compared with 1.0% for those weighing less than 1000 g and 4.8% for stillborn fetuses weighing 1000-2499 g. In the PCR studies, Ureaplasma spp. were by far the most common pathogens found and generally were more commonly found in association with inflammatory lesions.

CONCLUSIONS

Chorioamnionitis was the most common type of placental inflammatory lesion regardless of whether the placentas evaluated were from term controls, stillbirths or neonatal deaths. For stillbirths, inflammation in each inflammation category was more common than in the term controls and significantly more so for any inflammation, chorioamnionitis, intervillitis and villitis. For neonatal deaths, compared with the placentas of term controls, all inflammation categories were more common, but only significantly so for chorioamnionitis. Ureaplasma spp. were the most common organisms found in the placentas and were significantly associated with inflammation.

Endometrial Origins of Stillbirth (EOS), a case-control study of menstrual fluid to understand and prevent preterm stillbirth and associated adverse pregnancy outcomes: study protocol

INTRODUCTION

Current research aimed at understanding and preventing stillbirth focuses almost exclusively on the role of the placenta. The underlying origins of poor placental function leading to stillbirth, however, remain poorly understood. There is evidence demonstrating that the endometrial environment in which the embryo implants impacts not only the establishment of pregnancy but also the development of some pregnancy outcomes. Menstrual fluid has recently been applied to the study of menstrual disorders such as heavy menstrual bleeding or endometriosis, however, it has great potential in the study of adverse pregnancy outcomes. This study aims to identify differences in menstrual fluid and menstrual cycle characteristics of women who have experienced preterm stillbirth and other associated adverse pregnancy outcomes, compared with those who have not. The association between menstrual fluid composition and menstrual cycle characteristics will also be determined.

METHODS AND ANALYSIS

This is a case-control study of women who have experienced a late miscarriage, spontaneous preterm birth or preterm stillbirth or a pregnancy complicated by placental insufficiency (fetal growth restriction or pre-eclampsia), compared with those who have had a healthy term birth. Cases will be matched for maternal age, body mass index and gravidity. Participants will not currently be on hormonal therapy. Women will be provided with a menstrual cup and will collect their sample on day 2 of menstruation. Primary exposure measures include morphological and functional differences in decidualisation of the endometrium (cell types, immune cell subpopulations and protein composition secreted from the decidualised endometrium). Women will complete a menstrual history survey to capture menstrual cycle length, regularity, level of pain and heaviness of flow.

ETHICS AND DISSEMINATION

Ethics approval was obtained from Monash University Human Research Ethics Committee (27900) on 14/07/2021 and will be conducted in accordance with these conditions. Findings from this study will be disseminated through peer-reviewed publications and conference presentations.

Synoptic Reporting in Clinical Placental Pathology: A Preliminary Investigation Into Report Findings and Interobserver Agreement

INTRODUCTION

Placental pathology is key for investigating adverse pregnancy outcomes, however, lack of standardization in reporting has limited clinical utility. We evaluated a novel placental pathology synoptic report, comparing its robustness to narrative reports, and assessed interobserver agreement.

METHODS

100 singleton placentas were included. Histology slides were examined by 2 senior perinatal pathologists and 2 pathology residents using a synoptic report (32 lesions). Historical narrative reports were compared to synoptic reports. Kappa scores were calculated for interobserver agreement between senior, resident, and senior vs resident pathologists.

RESULTS

Synoptic reporting detected 169 (51.4%) lesion instances initially not included in historical reports. Amongst senior pathologists, 64% of all lesions examined demonstrated fair-to-excellent agreement (Kappa ≥0.41), with only 26% of Kappas ≥0.41 amongst those examined by resident pathologists. Well-characterized lesions (e.g., chorioamnionitis) demonstrated higher agreement, with lower agreement for uncommon lesions and those previously shown to have poor consensus.

DISCUSSION

Synoptic reporting is one proposed method to address issues in placenta pathology reporting. The synoptic report generally identifies more lesions compared to the narrative report, however clinical significance remains unclear. Interobserver agreement is likely related to differential in experience. Further efforts to improve overall standardization of placenta pathology reporting are needed.

Mitochondrial citrate metabolism and efflux regulate BeWo differentiation

Cytotrophoblasts fuse to form and renew syncytiotrophoblasts necessary to maintain placental health throughout gestation. During cytotrophoblast to syncytiotrophoblast differentiation, cells undergo regulated metabolic and transcriptional reprogramming. Mitochondria play a critical role in differentiation events in cellular systems, thus we hypothesized that mitochondrial metabolism played a central role in trophoblast differentiation. In this work, we employed static and stable isotope tracing untargeted metabolomics methods along with gene expression and histone acetylation studies in an established BeWo cell culture model of trophoblast differentiation. Differentiation was associated with increased abundance of the TCA cycle intermediates citrate and α-ketoglutarate. Citrate was preferentially exported from mitochondria in the undifferentiated state but was retained to a larger extent within mitochondria upon differentiation. Correspondingly, differentiation was associated with decreased expression of the mitochondrial citrate transporter (CIC). CRISPR/Cas9 disruption of the mitochondrial citrate carrier showed that CIC is required for biochemical differentiation of trophoblasts. Loss of CIC resulted in broad alterations in gene expression and histone acetylation. These gene expression changes were partially rescued through acetate supplementation. Taken together, these results highlight a central role for mitochondrial citrate metabolism in orchestrating histone acetylation and gene expression during trophoblast differentiation.

Machine learning-based placental clusters and their associations with adverse pregnancy outcomes

BACKGROUND

Placental abnormalities have been described in clinical convenience samples, with predominately adverse outcomes. Few studies have described placental patterns in unselected samples.

OBJECTIVE

We aimed to investigate associations between co-occurring placental features and adverse pregnancy outcomes in a prospective cohort of singletons.

METHODS

Data were from the Safe Passage study (U.S. and South Africa, 2007-2015). Before 24 weeks' gestation, participants were randomly invited to donate placental tissue at delivery for blinded, standardised pathological examination. We used hierarchical clustering to construct statistically derived groups using 60 placental features. We estimated associations between the placental clusters and select adverse pregnancy outcomes, expressed as unadjusted and adjusted risk ratios (RRs) and robust 95% confidence intervals (CI).

RESULTS

We selected a 7-cluster model. After collapsing 2 clusters to form the reference group, we labelled the resulting 6 analytic clusters according to the overarching category of their most predominant feature(s): severe maternal vascular malperfusion (n = 117), fetal vascular malperfusion (n = 222), other vascular malperfusion (n = 516), inflammation 1 (n = 269), inflammation 2 (n = 175), and normal (n = 706). Risks for all outcomes were elevated in the severe maternal vascular malperfusion cluster. For instance, in unadjusted analyses, this cluster had 12 times the risk of stillbirth (RR 12.07, 95% CI 4.20, 34.68) and an almost doubling in the risk of preterm delivery (RR 1.93, 95% CI 1.27, 2.93) compared with the normal cluster. Small infant size was more common among the abnormal clusters, with the highest unadjusted RRs observed in the fetal vascular malperfusion cluster (small for gestational age birth RR 2.99, 95% CI 2.24, 3.98, head circumference <10th percentile RR 2.86, 95% CI 1.60, 5.12). Upon adjustment for known risk factors, most RRs attenuated but remained >1.

CONCLUSION

Our study adds to the growing body of epidemiologic research, finding adverse pregnancy outcomes may occur through etiologic mechanisms involving co-occurring placental abnormalities.

Changes in Artery Diameters and Fetal Growth in Cases of Isolated Single Umbilical Artery

Background-There are conflicting data in the international literature on the risks of abnormal fetal growth in fetuses presenting an isolated single umbilical artery (SUA), and the pathophysiology of this complication is poorly understood. Objective-To evaluate if changes in diameter of the remaining umbilical artery in fetuses presenting an isolated SUA are associated with different fetal growth patterns. Study design-This was a two-center prospective longitudinal observational study including 164 fetuses diagnosed with a SUA at the 20-22-week detailed ultrasound examination and 200 control fetuses with a three-vessel cord. In all cases, the diameters of the cord vessels were measured in a transverse view of the central portion of the umbilical cord, and the number of cord vessels was confirmed at delivery. Logistic regression and nonparametric receiver operating characteristic (ROC) analysis were carried out to evaluate the association of the umbilical artery diameter in a single artery with small for-gestational age (SGA) and with fetal growth restriction (FGR). The impact of artery dimension was adjusted for maternal BMI, parity, ethnicity, side of the remaining umbilical artery and umbilical resistance index (RI) in the regression model. Results-A significantly (p < 0.001) larger mean diameter was found for the remaining artery in fetuses with SUA compared with controls (3.0 ± 0.9 vs. 2.5 ± 0.6 mm). After controlling for BMI and parity, we found no difference in umbilical resistance and side of the remaining umbilical artery between the SUA and control groups. A remaining umbilical artery diameter of >3.1 mm was found to be associated with a lower risk of FGR, but this association failed to be statistical significant (OR = 0.60, 95% CI = 0.33-1.09, p value = 0.089). We also found that the mean vein-to-artery area ratio was significantly (p < 0.001) increased in the SUA group as compared with the controls (2.4 ± 1.8 vs. 1.8 ± 0.9; mean difference = 0.6; Cohen's d = 0.46). Conclusion-In most fetuses with isolate SUA, the remaining artery diameter at 20-22 weeks is significantly larger than in controls. When there are no changes in the diameter and, in particular, if it remains <3.1 mm, the risk of abnormal fetal growth is higher, and measurements of the diameter of the remaining artery could be used to identify fetuses at risk of FGR later in pregnancy.

Mitochondrial citrate metabolism and efflux regulates trophoblast differentiation

Cytotrophoblasts fuse to form and renew syncytiotrophoblasts necessary to maintain placental health throughout gestation. During cytotrophoblast to syncytiotrophoblast differentiation, cells undergo regulated metabolic and transcriptional reprogramming. Mitochondria play a critical role in differentiation events in cellular systems, thus we hypothesized that mitochondrial metabolism played a central role in trophoblast differentiation. In this work, we employed static and stable isotope tracing untargeted metabolomics methods along with gene expression and histone acetylation studies in an established cell culture model of trophoblast differentiation. Trophoblast differentiation was associated with increased abundance of the TCA cycle intermediates citrate and α-ketoglutarate. Citrate was preferentially exported from mitochondria in the undifferentiated state but was retained to a larger extent within mitochondria upon differentiation. Correspondingly, differentiation was associated with decreased expression of the mitochondrial citrate transporter (CIC). CRISPR/Cas9 disruption of the mitochondrial citrate carrier showed that CIC is required for biochemical differentiation of trophoblasts. Loss of CIC resulted in broad alterations in gene expression and histone acetylation. These gene expression changes were partially rescued through acetate supplementation. Taken together, these results highlight a central role for mitochondrial citrate metabolism in orchestrating histone acetylation and gene expression during trophoblast differentiation.

Time-varying association between fetal death and gestational exposure to ambient fine particles: a nationwide epidemiological study of 49 million fetuses in the contiguous US from 1989 to 2004

BACKGROUND

Gestational exposure to fine particulate matter (PM2.5) has been reported to be associated with an increased risk of fetal death in recent studies, but earlier studies in the past century have usually reported a non-significant association. As such, it remains unknown whether this adverse effect of PM2.5 exposure varies with time.

METHODS

Nearly 49.2 million eligible birth and fetal death records from 1989 to 2004 were selected from the United States (US) birth and fetal death certificate datasets. For each record, the level of prenatal exposure to PM2.5 was taken as the average concentration in the mother's residential county during the entire gestational period, according to well-established estimates of monthly levels across the contiguous US. We first stratified the dataset by the month of the last menstrual period (LMP) and then independently evaluated the nationwide association between PM2.5 exposure and fetal death within each stratum using five typical logit models: unadjusted, covariate-adjusted, propensity-score, double robust, and diagnostic-score models. Finally, we conducted a meta-analysis to pool estimated LMP-specific associations and explored how the overall association varied by LMP month.

RESULTS

Different models showed temporal heterogeneity in the estimated association between PM2.5 exposure and fetal death. According to the meta-analysis, double robust model estimates were more homogeneous than the rest, and thus the model outcome was recognized as the main result. For each 1-µg/m3 increase in prenatal exposure to PM2.5, the pooled odds ratio (OR) of fetal death was estimated to be 1.08 [95% confidence interval (CI): 1.05, 1.10]. The LMP-specific ORs exhibited a slightly increasing trend and a significant seasonal pattern. Compared with the pooled OR among samples with the LMP in spring, the estimates for summer, fall and winter were higher by 11.1% (95% CI: 6.2%, 16.3%), 27.8% (95% CI: 22.1%, 33.8%) and 28.8% (95% CI: 23.7%, 34.1%), respectively. We also found that temporal patterns in the association between PM2.5 exposure and fetal death could be explained by several population-level indicators or modifiers (i.e. ethnicity, maternal age, gestational weight gain, previous pregnancy of abnormal termination and diabetes).

CONCLUSIONS

Prenatal exposure to PM2.5 can increase the risk of fetal death. The effects of PM2.5 exposure may be modified by complex factors, which leads to a time-varying association.

Placental and Umbilical Cord Anomalies Diagnosed by Two- and Three-Dimensional Ultrasound

The aim of this review is to present a wide spectrum of placental and umbilical cord pathologies affecting the pregnancy. Placental and umbilical cord anomalies are highly associated with high-risk pregnancies and may jeopardize fetal well-being in utero as well as causing a predisposition towards poor perinatal outcome with increased fetal and neonatal mortality and morbidity. The permanent, computerized perinatology databases of different international centers have been searched and investigated to fulfil the aim of this manuscript. An extended gallery of prenatal imaging with autopsy correlation in specific cases will help to provide readers with a useful iconographic tool and will assist with the understanding and definition of this critical obstetrical and perinatological issue.

A study on the placenta in stillbirth: an evaluation of molecular alterations through next generation sequencing

INTRODUCTION

Placental dysfunction is one of the most common causes of Intrauterine Fetal Demise (IUFD). Due to its characteristics, the placenta may be the target of molecular research aimed to investigate potential causes of IUFD. In the literature, there are no studies on human placentas that have investigated possible associations between somatic mutations and the occurrence of IUFD. The aim of this study was to identify the presence of gene mutations in placental tissues in a series of cases of IUFD and to evaluate potential correlations with placental microscopic findings.

MATERIALS AND METHODS

Thirty-seven samples of formalin-fixed and paraffin-embedded placental tissues were retrospectively selected from pregnancies ending in IUFD between 23rd to 40th week. Six control placentas of physiological pregnancies were included as controls. After sampling, made according to standardized protocol and conventional histopathological examination, placental tissues were subjected to DNA extraction and sequencing by means of Next Generation Sequencing with a 56-gene panel.

RESULTS

The most frequent mutation observed in 32/37 IUFD cases (86.5%) and absent in any of the 6 control placentas was in c-KIT gene, which is implicated in placental tissue differentiation. However, no significant correlation was found between the presence of individual gene mutations and placental histopatological findings.

DISCUSSION

As the present study found an elevated frequency of c-KIT mutation in IUFD, it further supports the hypothesis that c-KIT is involved in abnormal tissue differentiation leading to altered placental vascularization and function.

Platelet protease activated receptor 4 (PAR 4) receptor genotype is associated with an increased risk of preterm birth

BACKGROUND

Platelet protease activated receptor-4 (PAR4) Thr120 is a common genetic variant associated with increased platelet activity. Increased platelet activity is implicated in the pathogenesis of preeclampsia and preterm birth.

OBJECTIVE

Compare the rate of preeclampsia and preterm birth in pregnant individuals homozygous for PAR4 Thr120 variant vs not.

STUDY DESIGN

This is a prospective cohort study of patients who delivered November 2020-July 2021. Maternal blood collected on admission for PAR4 genotyping. The primary outcome was the rate of preeclampsia/gestational hypertension in those with Thr/Thr genotype compared with Ala/Thr or Ala/Ala. Secondary outcomes included rates of preterm birth and placental pathology.

RESULTS

Three hundred and twenty singletons were included and 52 (16.3%) were PAR4 Thr/Thr. Those PAR4 Thr/Thr were more likely to be Black (67.3% vs 29.5%, p < .001), younger (28 ± 6 vs 31 ± 6, p = .004), and have higher body mass index (35.2 ± 6.8 vs 33.1 ± 7.4, p = .047). There was no difference in preeclampsia/gestational hypertension (19.2% vs 22.8%, p = .705). Those Thr/Thr had a significantly higher rate of preterm birth (15.4% vs 3.7%, adjusted odds ratio [aOR] 4.04 [1.47-11.10], p = .007), indicated preterm birth because of fetal growth restriction or preeclampsia (5.8% vs 0.4%, aOR 10.03 [1.48-67.87], p = .02), spontaneous preterm birth (7.7% vs 2.2%, aOR 4.81 [1.27-18.27], p = .02), and placental intervillous thrombosis (18.5% vs 7.9%, aOR 4.12 [1.14-14.92], p = .03).

CONCLUSION

Platelet receptor PAR4 Thr120 is a common variant associated with an increased risk of placental vascular pathology and preterm birth in homozygous individuals. Although a cohort study cannot establish causation, this strong association warrants further exploration.

Value of Placental Examination in the Diagnostic Evaluation of Stillbirth

ObjectiveThe aim was to assess the contribution of placental examination in the etiologic investigation of stillbirth. Materials and Methods: A retrospective review of stillbirths that occurred after 14 weeks gestation was conducted for a one-year period. Twin pregnancies and fetuses without placentas were excluded. According to the fetoplacental examination, stillbirths were classified into etiologic groups. Results: A total of 147 stillbirths were selected. They were associated with placental, materno-fetal, fetal and multiple causes in 89 cases (61%), 23 cases (16%), 14 cases (9%) and 13 cases (9%), respectively. Unexplained stillbirths were observed in 8 cases (5%). Placental abnormalities were identified in 132/147 cases (90%). They were consistent with vascular, inflammatory and developmental lesions in 82/132 cases (61%), 28/132 cases (21%) and 18/132 cases (13%), respectively. Conclusion: Placental lesions were the main causes of stillbirth and were predominantly of vascular type including chronic villous hypoxia-ischemia and funicular anomalies.

Doppler evaluation of normal and abnormal placenta

Doppler techniques are needed for the evaluation of the intraplacental circulation and can be of great value in the diagnosis of placental anomalies. Highly sensitive Doppler techniques can differentiate between the maternal (spiral arteries) and fetal (intraplacental branches of the umbilical artery) components of the placental circulation and assist in the evaluation of the placental functional units. A reduced number of placental functional units can be associated with obstetric complications, such as fetal growth restriction. Doppler techniques can also provide information on decidual vessels and blood movement. Abnormal decidual circulation increases the risk of placenta accreta. Doppler evaluation of the placenta greatly contributes to the diagnosis and clinical management of placenta accreta, vasa previa, placental infarcts, placental infarction hematoma, maternal floor infarction, massive perivillous fibrin deposition and placental tumors. However, it has a limited role in the diagnosis and clinical management of placental abruption, placental hematomas, placental mesenchymal dysplasia and mapping of placental anastomoses in monochorionic twin pregnancies. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Placental pathology of resuscitated apparent stillbirth

Resuscitated apparent stillbirth (RAS) is defined as an infant with APGAR scores of 0 at 1 minute of life who receives successful resuscitation. Assessment of placental pathology is considered standard of care in such infants, but the clinical significance of these placental findings as they relate to clinical outcomes has yet to be described within the literature. We report the findings of a retrospective study of placental pathology as defined by the Amsterdam and Dublin criteria of RAS infants born in South Australia over an 8-year period. The aim of this study was to assess whether placental pathology was able to predict RAS clinical outcomes of death, survival with adverse neurological outcomes, and survival with normal neurological outcomes. The RAS cohort within our study is small, reflecting the low incidence of RAS. Of the 25 RAS subjects 16 survived, five with abnormal neurological outcomes and 11 with normal neurological outcomes. No statistically significant difference was seen between the clinical outcome groups in the incidence of specific macroscopic and microscopic placental findings. No sentinel lesion was seen in any one clinical outcome group. Relevant placental pathology was found in all but one subject validating the role of placental pathology in determination of the aetiology of RAS. The most common finding was maternal vascular malperfusion. Placental pathology in RAS infants remains relevant but is unable to contribute to the matrix of predictive information available to the clinician and family.

Inducible knockout of syncytin-a leads to poor placental glucose transport in mice

INTRODUCTION

Cell-cell fusion of cytotrophoblasts into the syncytiotrophoblast layer is a key process in placental development. Syncytin, an endogenous retroviral envelope protein, is expressed in placental trophoblasts and specifically mediates syncytiotrophoblast layer formation. Syncytin deficiency has been observed in fetal growth-restricted placentas. Abnormal fetal growth, especially fetal growth restriction, is associated with the decreased expression of glucose transporters. Here, we aimed to determine the role of syncytin in fetal growth restriction in placental glucose transport capacity.

METHODS

To better explore the function of syncytin in fetal growth-restricted placenta, we generated an inducible knockout mouse model of syncytin-a gene. The expression levels of glucose transporters in BeWo cells were measured before and after HERV-W knockdown.

RESULTS

Syncytin-A disruption was associated with significant abnormalities in placental and fetal development in mice. Syncytin-A destruction causes extensive abnormalities in the maternal-fetal exchange structures in the labyrinth, including an extremely reduced number and dramatically irregular distribution of fetal vessels. Moreover, glucose transporter 1, glucose transporters 3, and connexin 26 expression levels decreased after E14.5. Consistently, low glucose transporter 1, glucose transporter 3, and connexin 26 levels were observed in HERV-W-silenced BeWo cells.

DISCUSSION

Syncytin-A is crucial for both syncytiotrophoblast layer development and morphogenesis, suggesting that syncytin-A disruption leads to fetal growth restriction associated with abnormalities in the maternal-fetal exchange barrier and decreased glucose transport.

Prescribing for pregnancy: chronic hypertension

An increasing number of women who become pregnant have pre-existing hypertension. For this group of women, a proportion will develop pre-eclampsia or severe hypertension which can impact on maternal and fetal well-being. Women with raised blood pressure should be offered reliable contraception when they do not wish to conceive and pre-conception counselling to address pregnancy-related concerns and advice on preparation for pregnancy and the use of medicines. For women with a history of hypertension, the smallest number of safe medicines at the lowest effective doses should be used while preparing for and during pregnancy. This article forms part of the series of prescribing for pregnancy and discusses the impact of hypertension on pregnancy, the impact of pregnancy on hypertension and options for treatment.

Trophoblast inclusions and adverse birth outcomes

OBJECTIVE

Trophoblast inclusions-cross sections of abnormal trophoblast bilayer infoldings-have previously been associated with aneuploidy, placenta accreta, and prematurity. This study was conducted to establish the relationship between trophoblast inclusions and a range of placental, pregnancy, and birth outcomes in a patient population with high smoking and alcohol exposure. Specifically, we sought to evaluate the association between the presence of trophoblast inclusions and 1) three primary birth outcomes: full-term birth, preterm birth, and stillbirth; 2) gestational age at delivery; and 3) specific placental pathologies.

METHODS

Two slides containing chorionic villi were evaluated from 589 placentas that were collected from Stellenbosch University in Cape Town, South Africa as part of the prospective, multicenter cohort Safe Passage Study of the Prenatal Alcohol and SIDS and Stillbirth Network. The subsample included 307 full-term live births, 212 preterm live births, and 70 stillbirths.

RESULTS

We found that the odds of identifying at least one trophoblast inclusion across two slides of chorionic villi was significantly higher for placentas from preterm compared to term liveborn deliveries (OR = 1.74; 95% CI: 1.22, 2.49, p = 0.002), with an even greater odds ratio for placentas from stillborn compared to term liveborn deliveries (OR = 4.95; 95% CI: 2.78, 8.80, p < 0.001). Gestational age at delivery was inversely associated with trophoblast inclusion frequency. Trophoblast inclusions were significantly associated with small for gestational age birthweight, induction of labor, villous edema, placental infarction, and inflammation of the chorionic plate.

CONCLUSIONS

The novel associations that we report warrant further investigation in order to understand the complex network of biological mechanisms through which the factors that lead to trophoblast inclusions may influence or reflect the trajectory and health of a pregnancy. Ultimately, this line of research may provide critical insights that could inform both clinical and research applications.

Maternal and fetal vascular lesions of malperfusion in the placentas associated with fetal and neonatal death: results of a prospective observational study

BACKGROUND

Fetal death is one of the major adverse pregnancy outcomes and is common in low- and middle-income countries. Placental lesions may play an important role in the etiology of fetal and neonatal deaths. Previous research relating placental lesions to fetal death causation was hindered by a lack of agreement on a placental classification scheme. The Amsterdam consensus statement that was published in 2016 focused its attention on malperfusions in the maternal and fetal placental circulations.

OBJECTIVE

This study aimed to investigate the relationships of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths, focusing on the most important maternal clinical conditions in the pathway to fetal and neonatal deaths, such as maternal hypertension, antepartum hemorrhage, and decreased fetal growth.

STUDY DESIGN

This was a prospective, observational cohort study conducted at 2 Asian sites. The data collected included clinical history, gross and histologic evaluations of the placenta, and several other investigations and were used to determine the cause of death. The placenta was evaluated at both sites using the Amsterdam consensus framework. We estimated the risk of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths.

RESULTS

Between July 2018 and January 2020 in India and Pakistan, 1633 women with placentas available for the study provided consent. Of these women, 814 had fetal deaths, 618 had preterm live births and subsequent neonatal deaths, and 201 had term live births. The prevalence of maternal vascular malperfusion was higher in the placentas associated with fetal deaths (58.4%) and preterm neonatal deaths (31.1%) than in the placentas associated with term live births (15.4%). Adjusting for site, maternal vascular malperfusion had a relative risk of 3.88 (95% confidence interval, 2.70-5.59) in fetal deaths vs term live births and a relative risk of 2.07 (95% confidence interval, 1.41-3.02) in preterm neonatal deaths vs term live births. Infarcts and distal villous hypoplasia were the most common histologic components of maternal vascular malperfusion. Compared with maternal vascular malperfusion (58.4%), fetal vascular malperfusion was less common in the placentas associated with fetal deaths (19.0%). However, there were higher frequencies of fetal vascular malperfusion in the placentas associated with fetal deaths (19.0%) than in placentas associated with neonatal deaths (8.3%) or term live birth (5.0%). Adjusting for site, fetal vascular malperfusion had a relative risk of 4.09 (95% confidence interval, 2.15-7.75) in fetal deaths vs term live births and a relative risk of 1.77 (95% confidence interval, 0.90-3.49) in preterm neonatal deaths vs term live births. Furthermore, there was a higher incidence of maternal vascular malperfusion in cases of maternal hypertension (71.4%), small for gestational age (69.9%), and antepartum hemorrhage (59.1%) than in cases of fetal deaths with none of these conditions (43.3%). There was no significant difference in the occurrence of fetal vascular malperfusion in the 4 clinical categories.

CONCLUSION

Histologic examination of the placenta, especially for malperfusion disorders, is crucial in elucidating pathways to fetal and neonatal deaths in preterm infants. In particular, focusing on placental maternal and fetal vascular malperfusions during pregnancy is a means to identify fetuses at risk of fetal death and is an important strategy to reduce the risk of fetal death early delivery. We hope that the increased risk of fetal and neonatal deaths in these pregnancies can be reduced by the development of an intervention that reduces the likelihood of developing maternal and fetal vascular malperfusion.

Association of Insulin-like Growth Factor-II Apa1 and MspI Polymorphisms with Intrauterine Growth Restriction Risk

BackgroundInsulin-like growth factor-II (IGF-II) has a prominent role in fetal growth and development. The aim of this study was to investigate the association of IGF-II Apa1 and MspI polymorphisms with intrauterine growth restriction (IUGR) risk. Methods: A total of 45 infants with IUGR and 45 infants appropriate for gestational (AGA) were enrolled. Genotyping of Apa1 and MspI polymorphisms was assayed by PCR-RFLP approach. Results: The heterozygote genotype (AG) of IGF-II Apa1 CT was associated with an increased risk of IUGR. Genotypes and alleles of IGF-II MspI polymorphism had no significant association with IUGR susceptibility (P > 0.05). Conclusions: The current study suggests that IGF-II Apa1 polymorphism is associated with an increased risk of IUGR, while IGF-II MspI showed no association with IUGR. Thus, IGF-II Apa1 polymorphism could be used as a relevant molecular marker to identify the fetus at risk of developing IUGR.

Maternal and fetal characteristics and causes of stillbirth in a tertiary care hospital of Nepal: secondary analysis of registry-based surveillance data

OBJECTIVES

Stillbirth is one of the vital indicators of quality care. This study aimed to determine maternal-fetal characteristics and causes of stillbirth in Nepal.

DESIGN

Secondary analysis of single-centred registry-based surveillance data.

SETTING

The study was conducted at the Department of Obstetrics and Gynecology, Chitwan Medical College Teaching Hospital, a tertiary care hospital located in Bharatpur, Nepal.

PARTICIPANTS

All deliveries of intrauterine fetal death, at or beyond 22 weeks' period of gestation and/or birth weight of 500 g or more, conducted between 16 July 2017 and 15 July 2019 were included in the study.

MAIN OUTCOME MEASURES

The primary outcome measure of this study was stillbirth, and the secondary outcome measures were maternal and fetal characteristics and cause of stillbirth.

RESULTS

Out of 5282 institutional deliveries conducted over 2 years, 79 (1.5%) were stillbirths, which gives the stillbirth rate of 15 per 1000 births. Of them, the majority (75; 94.9%) were vaginal delivery and only four (5.1%) were caesarean section (p<0.0001). The proportion of the macerated type of stillbirth was more than that of the fresh type (58.2% vs 41.8%; p=0.13). Only half of the mothers who experienced stillbirth had received antenatal care. While the cause of fetal death was unknown in one-third of cases (31.6%; 25/79), among likely causes, the most common was maternal hypertension (29.1%), followed by intrauterine infection (8.9%) and fetal malpresentation (7.6%). Four out of 79 stillbirths (5%) had a birth defect.

CONCLUSION

High rate of stillbirths in Nepal could be due to the lack of quality antenatal care. The country's health systems should be strengthened so that pregnancy-related risks such as maternal hypertension and infections are identified early on. Upgrading mothers' hygiene and health awareness is equally crucial in reducing fetal deaths in low-resource settings.

Indications for Outpatient Antenatal Fetal Surveillance: ACOG Committee Opinion, Number 828

ABSTRACT

The purpose of this Committee Opinion is to offer guidance about indications for and timing and frequency of antenatal fetal surveillance in the outpatient setting. Antenatal fetal surveillance is performed to reduce the risk of stillbirth. However, because the pathway that results in increased risk of stillbirth for a given condition may not be known and antenatal fetal surveillance has not been shown to improve perinatal outcomes for all conditions associated with stillbirth, it is challenging to create a prescriptive list of all indications for which antenatal fetal surveillance should be considered. This Committee Opinion provides guidance on and suggests surveillance for conditions for which stillbirth is reported to occur more frequently than 0.8 per 1,000 (the false-negative rate of a biophysical profile) and which are associated with a relative risk or odds ratio for stillbirth of more than 2.0 compared with pregnancies without the condition. Table 1 presents suggestions for the timing and frequency of testing for specific conditions. As with all testing and interventions, shared decision making between the pregnant individual and the clinician is critically important when considering or offering antenatal fetal surveillance for individuals with pregnancies at high risk for stillbirth or with multiple comorbidities that increase the risk of stillbirth. It is important to emphasize that the guidance offered in this Committee Opinion should be construed only as suggestions; this guidance should not be construed as mandates or as all encompassing. Ultimately, individualization about if and when to offer antenatal fetal surveillance is advised.

Preventable stillbirths in India and Pakistan: a prospective, observational study

OBJECTIVE

Stillbirths occur 10-20 times more frequently in low-income settings compared with high-income settings. We created a methodology to define the proportion of stillbirths that are potentially preventable in low-income settings and applied it to stillbirths in sites in India and Pakistan.

DESIGN

Prospective observational study.

SETTING

Three maternity hospitals in Davangere, India and a large public hospital in Karachi, Pakistan.

POPULATION

All cases of stillbirth at ≥20 weeks of gestation occurring from July 2018 to February 2020 were screened for participation; 872 stillbirths were included in this analysis.

METHODS

We prospectively defined the conditions and gestational ages that defined the stillbirth cases considered potentially preventable. Informed consent was sought from the parent(s) once the stillbirth was identified, either before or soon after delivery. All information available, including obstetric and medical history, clinical course, fetal heart sounds on admission, the presence of maceration as well as examination of the stillbirth after delivery, histology, and polymerase chain reaction for infectious pathogens of the placenta and various fetal tissues, was used to assess whether a stillbirth was potentially preventable.

MAIN OUTCOME MEASURES

Whether a stillbirth was determined to be potentially preventable and the criteria for assignment to those categories.

RESULTS

Of 984 enrolled, 872 stillbirths at ≥20 weeks of gestation met the inclusion criteria and were included; of these, 55.5% were deemed to be potentially preventable. Of the 649 stillbirths at ≥28 weeks of gestation and ≥1000 g birthweight, 73.5% were considered potentially preventable. The most common conditions associated with a potentially preventable stillbirth at ≥28 weeks of gestation and ≥1000 g birthweight were small for gestational age (SGA) (52.8%), maternal hypertension (50.2%), antepartum haemorrhage (31.4%) and death that occurred after hospital admission (15.7%).

CONCLUSIONS

Most stillbirths in these sites were deemed preventable and were often associated with maternal hypertension, antepartum haemorrhage, SGA and intrapartum demise.

TWEETABLE ABSTRACT

Most stillbirths are preventable by better care for women with hypertension, growth restriction and antepartum haemorrhage.

Late-onset intrauterine growth restriction and HHV-6 infection: A pilot study

Late-onset Intrauterine growth restriction (IUGR) refers to impaired growth and development of the fetus, characterized by placental morphological abnormalities that affect the fetus's supply of nutrients. Human leukocyte antigen-G (HLA-G) is physiologically expressed during pregnancy, but decreased in normal placenta during the last weeks of gestation possibly inducing childbirth. Several viruses involved in congenital infection, such as herpesviruses, exploit HLA-G expression as an immune-escape mechanism. To date, despite different congenital herpetic infections having been associated with late IUGR, no direct implication of Human herpesvirus 6 (HHV-6) infection has been reported. We evaluated HLA-G expression and HHV-6 infection in 11 placentas from late-onset IUGR newborns and 11 placentas from uncomplicated pregnancies by histopathological and immunohistochemistry analysis. We found higher levels of HLA-G expression and HHV-6 presence in IUGR placenta samples compared with control placenta samples. We report HHV-6 staining in IUGR placenta samples, characterized by high HLA-G expression. These preliminary data suggest a possible involvement of HHV-6 infection in HLA-G deregulation that might affect vessel remodeling and prevent the correct pregnancy outcome in the IUGR condition.

Reduced fetal growth velocity precedes antepartum fetal death

OBJECTIVES

To determine whether decreased fetal growth velocity precedes antepartum fetal death and to evaluate whether fetal growth velocity is a better predictor of antepartum fetal death compared to a single fetal biometric measurement at the last available ultrasound scan prior to diagnosis of demise.

METHODS

This was a retrospective, longitudinal study of 4285 singleton pregnancies in African-American women who underwent at least two fetal ultrasound examinations between 14 and 32 weeks of gestation and delivered a liveborn neonate (controls; n = 4262) or experienced antepartum fetal death (cases; n = 23). Fetal death was defined as death diagnosed at ≥ 20 weeks of gestation and confirmed by ultrasound examination. Exclusion criteria included congenital anomaly, birth at < 20 weeks of gestation, multiple gestation and intrapartum fetal death. The ultrasound examination performed at the time of fetal demise was not included in the analysis. Percentiles for estimated fetal weight (EFW) and individual biometric parameters were determined according to the Hadlock and Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (PRB/NICHD) fetal growth standards. Fetal growth velocity was defined as the slope of the regression line of the measurement percentiles as a function of gestational age based on two or more measurements in each pregnancy.

RESULTS

Cases had significantly lower growth velocities of EFW (P < 0.001) and of fetal head circumference, biparietal diameter, abdominal circumference and femur length (all P < 0.05) compared to controls, according to the PRB/NICHD and Hadlock growth standards. Fetuses with EFW growth velocity < 10^th percentile of the controls had a 9.4-fold and an 11.2-fold increased risk of antepartum death, based on the Hadlock and customized PRB/NICHD standards, respectively. At a 10% false-positive rate, the sensitivity of EFW growth velocity for predicting antepartum fetal death was 56.5%, compared to 26.1% for a single EFW percentile evaluation at the last available ultrasound examination, according to the customized PRB/NICHD standard.

CONCLUSIONS

Given that 74% of antepartum fetal death cases were not diagnosed as small-for-gestational age (EFW < 10^th percentile) at the last ultrasound examination when the fetuses were alive, alternative approaches are needed to improve detection of fetuses at risk of fetal death. Longitudinal sonographic evaluation to determine growth velocity doubles the sensitivity for prediction of antepartum fetal death compared to a single EFW measurement at the last available ultrasound examination, yet the performance is still suboptimal. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Methodology for Biometrical Analysis of the Placenta: Feasibility and Reproducibility

The role of a healthy placenta as the interface between mother and fetus, which regulates the intrauterine environment and affects fetal and pregnancy outcomes, points to placental examination as a potentially useful diagnostic tool. Placental macroscopic and microscopic patterns are routinely evaluated when pregnancy complications occur. Moreover, placental measures particularly the ratio between fetal and placental weight have been reported to correlate with maternal characteristics, such as BMI as well as with birth-weight and fetal gender. Our pilot study evaluates the feasibility of the placental measures' reproducibility intra-operators. We enrolled 50 consecutive singleton pregnancies including physiological pregnancies and any pre-existing maternal disease or maternal and fetal complication. We conducted a macroscopic analysis of fetal adnexa with four different operators assessing pathological findings or other abnormalities. Intra-class correlation coefficient (ICC) and Cohen and Fleiss kappa coefficient were used to assess the degree of consistency between operators. The results of our study show that the placental morphometric analysis is a reproducible method.

Case of placental insufficiency and premature delivery in a Fontan pregnancy: physiological insights and considerations on risk stratification

OBJECTIVES

The coexistence of two complex physiologies such as Fontan and pregnancy is still not fully understood. We aim to add a unique and essential knowledge to help our colleagues in the management of Fontan patients that undergo pregnancy as well as the fetus and the placenta perfusion.

METHODS AND RESULTS

We analyse the coexistence of Fontan and pregnancy physiology on a complex case of a woman with hypoplastic left heart syndrome palliated with a univentricular repair who became pregnant, delivered very prematurely and had atypical placental findings.

CONCLUSION

Histopathological analysis of the placenta could help us to refine the understanding of Fontan physiology adaptation during pregnancy, predict women and fetal outcomes as well as to plan a better pre-pregnancy status. However, further evidence is needed in order to reach a more solid and unified conclusion.

Diagnostic accuracy of fetal growth charts for placenta-related fetal growth restriction

INTRODUCTION

The choice of fetal growth chart to be used in antenatal screening for fetal growth restriction (FGR) has an important impact on the proportion of fetuses diagnosed as small for gestational age (SGA), and on the detection rate for FGR. We aimed to compare diagnostic accuracy of SGA diagnosed using four different common fetal growth charts [Hadlock, Intergrowth-21st (IG21), World Health Organization (WHO), and National Institute of Child Health and Human Development (NICHD)], for abnormal placental pathology.

METHODS

A secondary analysis of data from a prospective cohort study in low-risk nulliparous women. The exposure was SGA (birthweight <10th centile for gestational age) using each of the four charts. The outcomes were one of three types of abnormal placental pathology associated with fetal growth restriction: maternal vascular malperfusion (MVM), chronic villitis, and fetal vascular malperfusion.

RESULTS

A total of 742 nulliparous women met the study criteria. The proportion of SGA was closest to the expected rate of 10% using the Hadlock chart (12.7%). The detection rates (DR) and false positive rates (FPR) for MVM pathology were similar for the Hadlock (DR = 53.1%, FPR = 10.8%), WHO (DR = 59.4%, FPR = 14.2%), and NICHD (DR = 53.1%, FPR = 12.3%) charts, and each was superior when compared to the IG21 chart (DR = 34.4%, FPR = 3.8%, p < 0.001). The diagnosis of SGA was associated with increased risks of preeclampsia and preterm birth for all four charts.

DISCUSSION

The selection of fetal growth chart to be used in screening programs for FGR has important implications with regard to the false positive and detection rate for FGR.

Stillbirth 2010-2018: a prospective, population-based, multi-country study from the Global Network

BACKGROUND

Stillbirth rates are high and represent a substantial proportion of the under-5 mortality in low and middle-income countries (LMIC). In LMIC, where nearly 98% of stillbirths worldwide occur, few population-based studies have documented cause of stillbirths or the trends in rate of stillbirth over time.

METHODS

We undertook a prospective, population-based multi-country research study of all pregnant women in defined geographic areas across 7 sites in low-resource settings (Kenya, Zambia, Democratic Republic of Congo, India, Pakistan, and Guatemala). Staff collected demographic and health care characteristics with outcomes obtained at delivery. Cause of stillbirth was assigned by algorithm.

RESULTS

From 2010 through 2018, 573,148 women were enrolled with delivery data obtained. Of the 552,547 births that reached 500 g or 20 weeks gestation, 15,604 were stillbirths; a rate of 28.2 stillbirths per 1000 births. The stillbirth rates were 19.3 in the Guatemala site, 23.8 in the African sites, and 33.3 in the Asian sites. Specifically, stillbirth rates were highest in the Pakistan site, which also documented a substantial decrease in stillbirth rates over the study period, from 56.0 per 1000 (95% CI 51.0, 61.0) in 2010 to 44.4 per 1000 (95% CI 39.1, 49.7) in 2018. The Nagpur, India site also documented a substantial decrease in stillbirths from 32.5 (95% CI 29.0, 36.1) to 16.9 (95% CI 13.9, 19.9) per 1000 in 2018; however, other sites had only small declines in stillbirth over the same period. Women who were less educated and older as well as those with less access to antenatal care and with vaginal assisted delivery were at increased risk of stillbirth. The major fetal causes of stillbirth were birth asphyxia (44.0% of stillbirths) and infectious causes (22.2%). The maternal conditions that were observed among those with stillbirth were obstructed or prolonged labor, antepartum hemorrhage and maternal infections.

CONCLUSIONS

Over the study period, stillbirth rates have remained relatively high across all sites. With the exceptions of the Pakistan and Nagpur sites, Global Network sites did not observe substantial changes in their stillbirth rates. Women who were less educated and had less access to antenatal and obstetric care remained at the highest burden of stillbirth.

STUDY REGISTRATION

Clinicaltrials.gov (ID# NCT01073475).

Fetal morphological features and abnormalities associated with equine early pregnancy loss

BACKGROUND

Early pregnancy loss (EPL) occurs in approximately 8% of equine pregnancies, although the aetiology is mostly unknown and embryonic/fetal morphological abnormalities associated with EPL are not defined.

OBJECTIVES

To compare the morphology of EPL to clinically normal embryos/fetuses and previously described embryonic/fetal developmental milestones. To identify morphological abnormalities associated with equine EPL.

STUDY DESIGN

Observational case-control study.

METHODS

Embryos/fetuses were obtained from clinically normal Thoroughbred and pony pregnancies (n = 11) and following EPL from Thoroughbred mares (n = 27). The crown-rump length (CRL) of embryos/fetuses was measured and macroscopic morphology and developmental age were determined independently by three blinded examiners. Sagittal sections of EPL (n = 13) and control (n = 6) embryos/fetuses were assessed microscopically. Fisher's exact test was used to determine significance (P < .05) and correlations were expressed by Pearson coefficient.

RESULTS

Age and CRL were strongly positively correlated in clinically normal Thoroughbred and reference (n = 15, R = .9 (95% CI: 0.8-1.0), R²  = .9, P < .0001) but not EPL embryos/fetuses (n = 19, R = .1 (95% CI: -0.4 to 0.5), R²  = .01, P = .75). Relative to controls, the CRL of EPL embryos/fetuses was smaller, with evidence of intrauterine growth retardation (IUGR) in 3/8 fetuses assessed. In 9/13 EPL embryos/fetuses, nonspecific neural tissue alterations were identified including disruption of developing pros-, mes- and rhombencephalon and the presence of haemosiderin, indicating premortem haemorrhage. Failed neural tube closure was identified in 1/13 EPL embryos/fetuses. Subcutaneous haemorrhage was present in 14/27 EPL embryos/fetuses.

MAIN LIMITATIONS

Autolysis significantly affected 15/27 EPL embryos/fetuses, excluding them from complete assessment. The IUGR reference cut-off values were based on a small number of controls.

CONCLUSIONS

Morphological features associated with equine EPL were a mismatch between embryonic/fetal size and age, and alterations of the developing neural tissue and localised subcutaneous haemorrhage. Failed neural tube closure was confirmed as a rare specific abnormality.

Umbilical Cord Abnormalities and Stillbirth

OBJECTIVE

Umbilical cord abnormalities are commonly cited as a cause of stillbirth, but details regarding these stillbirths are rare. Our objective was to characterize stillbirths associated with umbilical cord abnormalities using rigorous criteria and to examine associated risk factors.

METHODS

The Stillbirth Collaborative Research Network conducted a case-control study of stillbirth and live births from 2006 to 2008. We analyzed stillbirths that underwent complete fetal and placental evaluations and cause of death analysis using the INCODE (Initial Causes of Fetal Death) classification system. Umbilical cord abnormality was defined as cord entrapment (defined as nuchal, body, shoulder cord accompanied by evidence of cord occlusion on pathologic examination); knots, torsions, or strictures with thrombi, or other obstruction by pathologic examination; cord prolapse; vasa previa; and compromised fetal microcirculation, which is defined as a histopathologic finding that represents objective evidence of vascular obstruction and can be used to indirectly confirm umbilical cord abnormalities when suspected as a cause for stillbirth. We compared demographic and clinical factors between women with stillbirths associated with umbilical cord abnormalities and those associated with other causes, as well as with live births. Secondarily, we analyzed the subset of pregnancies with a low umbilical cord index.

RESULTS

Of 496 stillbirths with complete cause of death analysis by INCODE, 94 (19%, 95% CI 16-23%) were associated with umbilical cord abnormality. Forty-five (48%) had compromised fetal microcirculation, 27 (29%) had cord entrapment, 26 (27%) knots, torsions, or stricture, and five (5%) had cord prolapse. No cases of vasa previa occurred. With few exceptions, maternal characteristics were similar between umbilical cord abnormality stillbirths and non-umbilical cord abnormality stillbirths and between umbilical cord abnormality stillbirths and live births, including among a subanalysis of those with hypo-coiled umbilical cords.

CONCLUSION

Umbilical cord abnormalities are an important risk factor for stillbirth, accounting for 19% of cases, even when using rigorous criteria. Few specific maternal and clinical characteristics were associated with risk.

Identification of the optimal growth chart and threshold for the prediction of antepartum stillbirth

PURPOSE

To evaluate the effect of the choice growth chart and threshold used to define small for gestational age (SGA) on the predictive value of SGA for placenta-related or unexplained antepartum stillbirth.

METHODS

A retrospective cohort study of all women with a singleton pregnancy who gave birth > 24 week gestation in a single center (2000-2016). The exposure of interest was SGA, defined as birth weight < 10th or < 25th centile according to three fetal growth charts (Hadlock et al., Radiology 181:129-133, 1991; intergrowth-21st (IG21), WHO 2017, and a Canadian birthweight-based reference-Kramer et al., Pediatrics 108:E35, 2001). The outcome of interest was antepartum stillbirth due to placental dysfunction or unknown etiology. Cases of stillbirth attributed to other specific etiologies were excluded.

RESULTS

A total of 49,458 women were included in the cohort. There were 103 (0.21%) cases of stillbirth due to placental dysfunction or unknown etiology. For cases in the early stillbirth cluster (≤ 30 weeks), the detection rate was high and was similar for the three ultrasound-based fetal growth charts of Hadlock, IG21, and WHO (range 83.3-87.0%). In contrast, the detection rate of SGA for cases in the late stillbirth cluster (> 30 weeks) was low, being highest for WHO and Hadlock (36.7% and 34.7%, respectively), and lowest for IG21 (18.4%). Using a threshold of the 25th centile increased the detection rate for stillbirth by approximately 15-20% compared with that achieved by the 10th centile cutoff.

CONCLUSION

At > 30 week gestation, the Hadlock or WHO fetal growth charts provided the best balance between detection rate and false positive rate for stillbirth.

Velamentous cord insertion: results from a rapid review of incidence, risk factors, adverse outcomes and screening

BACKGROUND

Velamentous cord insertion (VCI) is an umbilical cord attachment to the membranes surrounding the placenta instead of the central mass. VCI is strongly associated with vasa praevia (VP), where umbilical vessels lie in close proximity to the internal cervical os. VP leaves the vessels vulnerable to rupture, which can lead to fatal fetal exsanguination. Screening for VP using second-trimester transabdominal sonography (TAS) to detect VCI has been proposed. We conducted a rapid review investigating the quality, quantity and direction of evidence available on the epidemiology, screening test accuracy and post-screening management pathways for VCI.

METHODS

MEDLINE, Embase and the Cochrane Library were searched on 5 July 2016 and again on 11 October 2019, using general search terms for VP and VCI. Only peer-reviewed articles reporting on the epidemiology of VCI, the accuracy of the screening test and/or downstream management pathways for VCI pregnancies were included. Quality and risk of bias of each included study were assessed using pre-specified tools.

RESULTS

Forty-one relevant publications were identified; all but one were based on non-UK pregnancy cohorts, and most included relatively few VCI cases. The estimated incidence of VCI was 0.4-11% in singleton pregnancies, with higher incidence in twin pregnancies (1.6-40%). VCI incidence was also increased among pregnancies with one or more other risk factors, including in vitro fertilisation pregnancies or nulliparity. VCI incidence among women without any known risk factors was unclear. VCI was associated with adverse perinatal outcomes, most notably pre-term birth and emergency caesarean section in singleton pregnancies, and perinatal mortality in twins; however, associations varied across studies and the increased risk was typically low or moderate compared with pregnancies without VCI. In studies on limited numbers of cases, screening for VCI using TAS had good overall accuracy, driven by high specificity. No studies on post-screening management of VCI were identified.

CONCLUSIONS

Literature on VCI epidemiology and outcomes is limited and low-quality. The accuracy of second-trimester TAS and the benefits and harms of screening cannot be determined without prospective studies in large cohorts. Modelling studies may indicate the feasibility and value of studying the epidemiology of VCI and the potential impact of detecting VCI as part of a population screening programme for VP.

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.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

Diagnostic Utility of Pathological Investigations in Late Gestation Stillbirth: A Cohort Study

OBJECTIVE

Near term unexpected stillbirth is a common, complex diagnostic challenge. We review a large cohort of near term to term gestation unexpected fetal deaths to document the common patterns of pathology and evaluate the utility of various standard autopsy procedures.

METHODS

A total of 123 perinatal autopsies consisting of 94 intrauterine fetal deaths (IUFDs) and 29 intrapartum deaths (IPDs) were reviewed. Deaths were classified according to the laboratory investigations establishing cause of death.

RESULTS

Cause of death was attributable to placental pathology without autopsy in 55.3% of IUFD and 17% of IPD. Correlative findings at autopsy increased the ability to establish cause of death in 86.2% of IUFD and 62% of IPD. Histology was largely corroborative, with the brain, lungs, and heart demonstrating significant changes in 46%, 34.5%, and 13.8%, respectively. Microbiology was corroborative but demonstrated single organism growth in 6 of 29 cases of fatal acute chorioamnionitis. Newborn metabolic screening revealed only elevated thyroid-stimulating hormone levels in 3 cases, of questionable relevance. Aneuploidy was established by screening molecular studies in 5 IUFDs, all of which had external or visceral dysmorphism. Karyotype was established in 69 cases and was not contributory in any of the IPD: 3 IUFDs had changes of unknown significance. Cause of death was not established at autopsy in 9% of IUFD and 10% of IPD.

DISCUSSION

This is the largest uniformly investigated cohort of late gestation unexpected fetal deaths studied. We confirm the importance of both placental and fetal autopsy in establishing cause of death. Autopsy histology, microbiology, and cytogenetics provide important but largely corroborative data.

Hypertension during pregnancy and risk of stillbirth: challenges in a developing country

Objective: To explore the factors associated with hypertensive disorders of pregnancy (HDP) in women experiencing stillbirth (SB).Material and methods: It was an observational, analytical case-control study, done as part of the World Health Organization South-East Asian Region Office SB project. The epidemiological profile, history, clinical features, and investigations of stillborn cases having HDP were noted, an equal number of age and parity matched subjects with HDP having livebirth were taken as controls.Results: Out of 46,816 deliveries, 1239 (26.2/1000) were stillborn. The maternal causes contributed 374/1239 (30.2%) stillbirths according to the CODAC classification, HDP was the most common maternal cause (304/1239, 24.9%). Subjects with HDP were included as cases. On comparing the cases with controls it was found that significantly more number of cases had inadequate antenatal visits (p < .001, OR -4.8), two or more abortions (p < .001, OR -1.9), early onset of hypertension (p < .0001, OR -5.6) and complications such as fetal growth restriction (FGR) (p < .001, OR -2.3) and abruption (p < .001, OR -4.0). Women with preeclampsia were less likely to have SB compared to those with gestational or chronic hypertension (p = .0001, OR -2.3). The birth weight/placental weight ratio of more than eight had the highest odds ratio regarding contribution to SB among hypertensive women (p = .0001 OR -6.7).Conclusion: In women with HDP, adequate antenatal care would lead to the prevention of complications such as anemia, abruption, and FGR, and thus prevent SB. The high BW/PW ratio is a potential marker of risk of SB.

Maternal vascular malformation in the placenta is an indicator for fetal growth restriction irrespective of neonatal birthweight

INTRODUCTION

To study the association between placental pathology and neonatal birthweight and outcomes, and whether a combination of first trimester biomarkers and fetal growth velocity can predict placental lesions.

METHODS

The presence of maternal vascular malperfusion (MVM) lesions (Amsterdam criteria) was recorded in a retrospective cohort of singleton pregnancies in the Maastricht University Medical Centre, 2011-2018. First trimester maternal characteristics and PAPP-A, PlGF and sFlt-1 levels were collected. Fetal growth velocities were calculated (mm/week) from 20 to 32 weeks for abdominal circumference, biparietal diameter, head circumference and femur length. Data were compared between neonates with 'small for gestational age' (SGA < p10) and different categories of 'appropriate for gestational age (AGA)': AGAp10-30, AGAp30-50 and AGA > p50 (reference), using one-way ANOVA and post hoc test.

RESULTS

There were significantly more MVM lesions in the SGA group (94.6% p < .0001), but also in the AGAp10-30 (67.3% p < .0001) and AGAp30-50 (41.6% p = 0.002), compared to the reference AGA group (19.3%). The prediction of MVM for a 20% false-positive rate, with maternal characteristics was25.2%. The addition of birthweight percentile gave a prediction of 51.7% for MVM. However adding placental biomarkers and fetal growth velocities (instead of birthweight percentile) to the maternal characteristics, gave a prediction of 81.8% (PPV 49.5%, NPV 53.7%).

DISCUSSION

Placental MVM lesions correlated inversely with birthweight even in AGA neonates, and was associated with slower fetal growth and more adverse outcome in SGA neonates. A combination of first trimester biomarkers and fetal growth velocity had good prediction of placental MVM lesions, as an indicator of fetal growth restriction irrespective of neonatal weight.

Nicotine protects fetus against LPS-induced fetal growth restriction through ameliorating placental inflammation and vascular development in late pregnancy in rats

Our previous work has shown that nicotine suppressed lipopolysaccharide (LPS)-induced placental inflammation by inhibiting cytokine release as well as infiltration of leukocytes into the placenta through the cholinergic anti-inflammatory pathway. Nicotine also increased fetal survival and restored pup weight. In the present study, we aim to further investigate if fetal growth restriction (FGR) occurs with LPS treatment, and evaluate the protective effects of nicotine on fetuses in late gestation of rats. Pregnant Sprague–Dawley rats were divided into control group, nicotine group, LPS group and LPS + nicotine group. Rats were first pretreated with nicotine or vehicle by subcutaneous injection on gestation day (GD)14 and GD15, followed by LPS or vehicle intraperitoneal injection on GD16, and were killed on GD18. Loss of fetuses, number and weights of live fetuses and weights of placentas were recorded. Placentas were collected to evaluate placental pathology and determine inflammatory cytokines and vascular endothelial growth factor (VEGF) levels. We found that LPS treatment increased levels of placental inflammatory cytokines and placental pathological damage, decreased levels of VEGF, reduced number of live fetuses and induced FGR. Pretreatment with nicotine reversed LPS-induced high levels of placental inflammatory cytokines, low levels of placental VEGF and placental pathological damage, then rescued the number and weights of live fetuses. These data demonstrated that activation of the cholinergic anti-inflammatory pathway by nicotine protected fetus against LPS-induced FGR through ameliorating placental inflammation and vascular development in late pregnancy in rats. It may be an alternative therapeutic strategy for inflammation- induced FGR in late pregnancy.

The association of stillbirth with placental abnormalities in growth-restricted and normally grown fetuses

BACKGROUND

Stillbirth, defined as foetal death ≥20 weeks' gestation, is associated with poor foetal growth and is often attributed to placental abnormalities, which are also associated with poor foetal growth. Evaluating inter-relationships between placental abnormalities, poor foetal growth, and stillbirth may improve our understanding of the underlying mechanisms for some causes of stillbirth.

OBJECTIVE

Our primary objective was to determine whether poor foetal growth, operationalised as small for gestational age (SGA), mediates the relationship between placental abnormalities and stillbirth.

METHODS

We used data from the Stillbirth Collaborative Research Network study, a population-based case-control study conducted from 2006-2008. Our analysis included 266 stillbirths and 1135 livebirths. We evaluated associations of stillbirth with five types of placental characteristics (developmental disorders, maternal and foetal inflammatory responses, and maternal and foetal circulatory disorders) and examined mediation of these relationships by SGA. We also assessed exposure-mediator interaction. Models were adjusted for maternal age, race/ethnicity, education, body mass index, parity, and smoking status.

RESULTS

All five placental abnormalities were more prevalent in cases than controls. After adjustment for potential confounders, maternal inflammatory response (odds ratio [OR] 2.58, 95% confidence interval [CI] 1.77, 3.75), maternal circulatory disorders OR 4.14, 95% CI 2.93, 5.84, and foetal circulatory disorders OR 4.58, 95% CI 3.11, 6.74 were strongly associated with stillbirth, and the relationships did not appear to be mediated by SGA status. Associations for developmental disorders and foetal inflammatory response diverged for SGA and non-SGA births, and strong associations were only observed when SGA was not present.

CONCLUSIONS

Foetal growth did not mediate the relationships between placental abnormalities and stillbirth. The relationships of stillbirth with maternal and foetal circulatory disorders and maternal inflammatory response appear to be independent of poor foetal growth, while developmental disorders and foetal inflammatory response likely interact with foetal growth to affect stillbirth risk.

Combined diffusion-relaxometry MRI to identify dysfunction in the human placenta

Purpose

A combined diffusion‐relaxometry MR acquisition and analysis pipeline for in vivo human placenta, which allows for exploration of coupling between T2* and apparent diffusion coefficient (ADC) measurements in a sub 10‐minute scan time.

Methods

We present a novel acquisition combining a diffusion prepared spin echo with subsequent gradient echoes. The placentas of 17 pregnant women were scanned in vivo, including both healthy controls and participants with various pregnancy complications. We estimate the joint T2*‐ADC spectra using an inverse Laplace transform.

Results

T2*‐ADC spectra demonstrate clear quantitative separation between normal and dysfunctional placentas.

Conclusions

Combined T2*‐diffusivity MRI is promising for assessing fetal and maternal health during pregnancy. The T2*‐ADC spectrum potentially provides additional information on tissue microstructure, compared to measuring these two contrasts separately. The presented method is immediately applicable to the study of other organs.

Placental Pathology and Neuroimaging Correlates in Neonates with Congenital Heart Disease

Congenital heart disease (CHD) is an independent risk factor for brain injury, including stroke, and poor neurodevelopmental outcomes, and placental abnormalities may represent an additional risk factor for brain injury in neonates. The incidence and scope of placental pathology and relationship to fetal brain abnormalities in pregnancies complicated by fetal CHD has not been explored to our knowledge. In order to determine the prevalence of placental pathology findings and whether placental findings are associated with postnatal brain injury in pregnancies complicated by fetal CHD, we reviewed placental pathology reports for 51 pregnancies complicated by CHD and scored available postnatal, pre-operative brain MRI for brain pathology. Overall, 57% of CHD infants had abnormal placental pathology. Pregnancies complicated by CHD with aortic obstruction (AO) were significantly more likely than those with no obstruction to have abnormal placental pathology (79% vs. 44%). There was a trend toward more severe brain lesions amongst patients with brain lesions and placental abnormality (55% moderate/severe) compared to those without placental abnormality (11% moderate/severe). These data suggest that placental abnormalities are common in CHD and may have a compounding effect on brain lesions in this high-risk population.