Stillbirth and intrauterine fetal death: role of routine histopathological placental findings to determine cause of death

The Burden of Placental Histopathology in Stillbirths Associated With Maternal Obesity

OBJECTIVES

Obesity is an increasing health problem that has become a common medical disorder among women of childbearing age, representing worldwide a risk factor for stillbirth. The aim of the study is to evaluate the association between placental histopathologic findings and obesity in stillbirth.

METHODS

Placentas were analyzed according to the Amsterdam consensus statement. Histologic findings in stillbirth from obese and lean mothers were analyzed and compared with those observed in liveborn controls.

RESULTS

Stillbirth in obese mothers displayed placental pathology in all gestational ages, mostly at term of pregnancy. The most observed placental lesions were those consistent with maternal vascular malperfusion of the placental bed. Decidual arteriopathy and placental infarcts appeared specifically associated with maternal obesity. Moreover, obese women with stillbirth showed the highest cumulative number of placental lesions.

CONCLUSIONS

Considering the significant association between stillbirth, maternal obesity, and placental histopathologic findings, health care providers should be aware about the importance of placental examination in obese women, especially in stillborn cases. The high prevalence of lesions consistent with vascular malperfusion of the placental bed suggests that stillbirth prevention strategies in obese women should rely on the development of tools to study and improve decidual artery functioning early in pregnancy.

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.

Feasibility of INTACT (INcisionless TArgeted Core Tissue) biopsy procedure for perinatal autopsy

OBJECTIVES

To determine the feasibility and tissue yield of a perinatal incisionless ultrasound-guided biopsy procedure, the INcisionless Targeted Core Tissue (INTACT) technique, in the context of minimally invasive autopsy.

METHODS

Cases of perinatal death in which the parents consented for minimally invasive autopsy underwent postmortem magnetic resonance imaging and an INTACT biopsy procedure, defined as needle biopsy of organs via the umbilical cord, performed under ultrasound guidance. In each case, three cores of tissue were obtained from seven target organs (both lungs, both kidneys, heart, spleen and liver). Biopsy success was predefined as an adequate volume of the intended target organ for pathological analysis, as judged by a pathologist blinded to the case and biopsy procedure.

RESULTS

Thirty fetuses underwent organ sampling. Mean gestational age was 30 weeks (range, 18-40 weeks) and mean delivery-to-biopsy interval was 12 days (range, 6-22 days). The overall biopsy success rate was 153/201 (76.1%) samples, with the success rates in individual organs being highest for the heart and lungs (93% and 91%, respectively) and lowest for the spleen (11%). Excluding splenic samples, the biopsy success rate was 150/173 (86.7%). Histological abnormalities were found in 4/201 (2%) samples, all of which occurred in the lungs and kidneys of a fetus with pulmonary hypoplasia and multicystic kidney disease.

CONCLUSIONS

Incisionless ultrasound-guided organ biopsy using the INTACT procedure is feasible, with an overall biopsy success rate of over 75%. This novel technique offers the ideal combination of an imaging-led autopsy with organ sampling for parents who decline the conventional invasive approach. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

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.

Mothers with long QT syndrome are at increased risk for fetal death: findings from a multicenter international study

BACKGROUND

Most fetal deaths are unexplained. Long QT syndrome is a genetic disorder of cardiac ion channels. Affected individuals, including fetuses, are predisposed to sudden death. We sought to determine the risk of fetal death in familial long QT syndrome, in which the mother or father carries the long QT syndrome genotype. In addition, we assessed whether risk differed if the long QT syndrome genotype was inherited from the mother or father.

OBJECTIVE

This was a retrospective review of pregnancies in families with the 3 most common heterozygous pathogenic long QT syndrome genotypes in KCNQ1 (LQT1), KCNH2 (LQT2), or SCN5A (LQT3), which occur in approximately 1 in 2000 individuals. The purpose of our study was to compare pregnancy and birth outcomes in familial long QT syndrome with the normal population and between maternal and paternal carriers of the long QT syndrome genotype. We hypothesized that fetal death before (miscarriage) and after (stillbirths) 20 weeks gestation would be increased in familial long QT syndrome compared with the normal population and that the parent of origin would not affect birth outcomes.

STUDY DESIGN

Our study was a multicenter observational case series of 148 pregnancies from 103 families (80 mothers, 23 fathers) with familial long QT syndrome (60 with LQT1, 29 with LQT2, 14 with LQT3) who were recruited from 11 international centers with expertise in hereditary heart rhythm diseases, pediatric and/or adult electrophysiology, and high-risk pregnancies. Clinical databases from these sites were reviewed for long QT syndrome that occurred in men or women of childbearing age (18-40 years). Pregnancy outcomes (livebirth, stillbirth, and miscarriage), birthweights, and gestational age at delivery were compared among long QT syndrome genotypes and between maternal vs paternal long QT syndrome-affected status with the use of logistic regression analysis.

RESULTS

Most offspring (80%; 118/148) were liveborn at term; 66% of offspring (73/110) had long QT syndrome. Newborn infants of mothers with long QT syndrome were delivered earlier and, when the data were controlled for gestational age, weighed less than newborn infants of long QT syndrome fathers. Fetal arrhythmias were observed rarely, but stillbirths (fetal death at >20 weeks gestation) were 8 times more frequent in long QT syndrome (4% vs approximately 0.5%); miscarriages (fetal death at ≤20 weeks gestation) were 2 times that of the general population (16% vs 8%). The likelihood of fetal death was significantly greater with maternal vs paternal long QT syndrome (24.4% vs 3.4%; P=.036). Only 10% of all fetal deaths underwent postmortem long QT syndrome testing; 2 of 3 cases were positive for the family long QT syndrome genotype.

CONCLUSION

This is the first report to demonstrate that mothers with long QT syndrome are at increased risk of fetal death and to uncover a previously unreported cause of stillbirth. Our results suggest that maternal effects of long QT syndrome channelopathy may cause placental or myometrial dysfunction that confers increased susceptibility to fetal death and growth restriction in newborn survivors, regardless of long QT syndrome status.

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.

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 diffusion-weighted MRI in normal pregnancies and those complicated by placental dysfunction due to vascular malperfusion

INTRODUCTION

Our aim was to assess placental function by diffusion-weighted magnetic resonance imaging (MRI) using intravoxel incoherent motion (IVIM) analysis in uncomplicated pregnancies and pregnancies complicated by placental dysfunction.

METHODS

31 normal pregnancies and 9 pregnancies complicated by placental dysfunction (birthweight ≤ -2SD and histological signs of placental vascular malperfusion) were retrieved from our placental MRI research database. MRI was performed at gestational weeks 20.1-40.6 in a 1.5 T system using 10 b-values (0-1000 s/mm²). Regions of interest were drawn covering the entire placenta in five transverse slices. Diffusion coefficient (D), pseudodiffusion coefficient (D*) and perfusion fraction (f) were estimated by IVIM analysis.

RESULTS

In normal pregnancies, placental f decreased linearly with gestational age (r = -0.522, p = 0.002) being 26.2% at week 20 and 18.8% at week 40. D and D* were 1.57 ± 0.03 and 31.7 ± 3.1 mm²/s (mean ± SD), respectively, and they were not correlated with gestational age. In complicated pregnancies, f was significantly reduced (mean Z-score = -1.16; p = 0.02) when compared to the group of normal pregnancies, whereas D and D* did not differ significantly between groups. Subgroup analysis demonstrated that f was predominantly reduced in dysfunctional placentas characterized by fetal vascular malperfusion (mean Z-score = -2.11, p < 0.001) rather than maternal vascular malperfusion (mean Z-score = -0.40, p = 0.42). In addition, f was negatively correlated with uterine artery pulsatility index (r = -0.396, p = 0.01).

DISCUSSION

Among parameters obtained by the IVIM analysis, only f revealed significant differences between the normal and the dysfunctional placentas. Subgroup analysis suggests that placental f may be able to discriminate non-invasively between different histological types of vascular malperfusion.

When the Fetus Goes Still and the Birth Is Tragic: The Role of the Placenta in Stillbirths

Because of the critical role that placental structure and function plays during pregnancy, abnormal placental structure and function is closely related to stillbirth: when an infant dies before birth. However, understanding the role of the placental and specific lesions is incomplete, in part because of the variation in definitions of lesions and in classifying causes of stillbirths. Nevertheless, placental abnormalities are seen more frequently in stillbirths than live births, with placental abruption, chorioamnionitis, and maternal vascular malperfusion most commonly reported. Critically, some placental lesions affect the management of subsequent pregnancies. Histopathological examination of the placenta is recommended following stillbirth.

The Placental Basis of Fetal Growth Restriction

Placental dysfunction is a major contributing factor to fetal growth restriction. Placenta-mediated fetal growth restriction occurs through chronic fetal hypoxia owing to poor placental perfusion through a variety of mechanisms. Maternal vascular malperfusion is the most common placental disease contributing to fetal growth restriction; however, the role of rare placental diseases should not be overlooked. Although the features of maternal vascular malperfusion are identifiable on placental pathology, antepartum diagnostic methods are evolving. Placental imaging and uterine artery Doppler, used in conjunction with angiogenic growth factors (specifically placenta growth factor and soluble fms-like tyrosine kinase-1), play an increasingly important role.

Latest developments in post-mortem foetal imaging

A sustained decline in parental consent rates for perinatal autopsies has driven the development of less-invasive methods for death investigation. A wide variety of imaging modalities have been developed for this purpose and include post-mortem whole body magnetic resonance imaging (MRI), ultrasound, computed tomography (CT) and micro-focus CT techniques. These are also vital for "minimally invasive" methods, which include potential for tissue sampling, such as image guidance for targeted biopsies and laparoscopic-assisted techniques. In this article, we address the range of imaging techniques currently in clinical practice and those under development. Significant advances in high-field MRI and micro-focus CT imaging show particular promise for smaller and earlier gestation foetuses. We also review how MRI biomarkers such as diffusion-weighted imaging and organ volumetric analysis may aid diagnosis and image interpretation in the absence of autopsy data. Three-dimensional printing and augmented reality may help make imaging findings more accessible to parents, colleagues and trainees.

Inequalities and stillbirth in the UK: a meta-narrative review

OBJECTIVE

To review what is known about the relationship between stillbirth and inequalities from different disciplinary perspectives to inform stillbirth prevention strategies.

DESIGN

Systematic review using the meta-narrative method.

SETTING

Studies undertaken in the UK.

DATA SOURCES

Scoping phase: experts in field, exploratory electronic searches and handsearching. Systematic searches phase: Nine databases with no geographical or date restrictions. Non-English language studies were excluded.

STUDY SELECTION

Any investigation of stillbirth and inequalities with a UK component.

DATA EXTRACTION AND SYNTHESIS

Three authors extracted data and assessed study quality. Data were summarised, tabulated and presented graphically before synthesis of the unfolding storyline by research tradition; and then of the commonalities, differences and interplays between narratives into resultant summary meta-themes.

RESULTS

Fifty-four sources from nine distinctive research traditions were included. The evidence of associations between social inequalities and stillbirth spanned 70 years. Across research traditions, there was recurrent evidence of the social gradient remaining constant or increasing, fuelling repeated calls for action (meta-theme 1: something must be done). There was less evidence of an effective response to these calls. Data pertaining to socioeconomic, area and ethnic disparities were routinely collected, but not consistently recorded, monitored or reported in relation to stillbirth (meta-theme 2: problems of precision). Many studies stressed the interplay of socioeconomic status, deprivation or ethnicity with aggregated factors including heritable, structural, environmental and lifestyle factors (meta-theme 3: moving from associations towards intersectionality and intervention(s)). No intervention studies were identified.

CONCLUSION

Research investigating inequalities and stillbirth in the UK is underdeveloped. This is despite repeated evidence of an association between stillbirth risk and poverty, and stillbirth risk, poverty and ethnicity. A specific research forum is required to lead the development of research and policy in this area, which can harness the multiple relevant research perspectives and address the intersections between different policy areas.

PROSPERO REGISTRATION NUMBER

CRD42017079228.

Maternal Risk Factors for Stillbirth: A Registry-Based Study

Background and Objectives: The number of stillbirths has reduced more slowly than has maternal mortality or mortality in children younger than 5 years, which were explicitly targeted in the Millennium Development Goals. Placental pathologies and infection associated with preterm birth are linked to a substantial proportion of stillbirths. Appropriate preconception care and quality antenatal care that is accessible to all women has the potential to reduce stillbirth rates. The aim of the present study was to assess potential risk factors associated with stillbirth within maternal medical diseases and obstetric complications. Materials and Methods: Retrospective cohort study (2001-2014) was used to analyse data from the Medical Birth Register on stillbirth and live births as controls. Adjusted Odds ratios (aOR) with 95% confidence intervals (CI) were estimated. Multiple regression model adjusted for maternal age, parity and gestational age. Results: The stillbirth rate was 6.2 per 1000 live and stillbirths. The presence of maternal medical diseases greatly increased the risk of stillbirth including diabetes mellitus (aOR = 2.5; p < 0.001), chronic hypertension 3.1 (aOR = 3.1; p < 0.001) and oligohydromnios/polyhydromnios (aOR = 2.4; p < 0.001). Pregnancy complications such as intrauterine growth restriction (aOR = 2.2; p < 0.001) was important risk factor for stillbirth. Abruption was associated with a 2.8 odds of stillbirth. Conclusions: Risk factors most significantly associated with stillbirth include maternal history of chronic hypertension and abruptio placenta which is a common cause of death in stillbirth. Early identification of potential risk factors and appropriate perinatal management are important issues in the prevention of adverse fetal outcomes and preventive strategies need to focus on improving antenatal detection of fetal growth restriction.

Mechanisms of death in structurally normal stillbirths

Objectives To investigate mechanisms of in utero death in normally formed fetuses by measuring amniotic fluid (AF) biomarkers for hypoxia (erythropoietin [EPO]), myocardial damage (cardiac troponin I [cTnI]) and brain injury (glial fibrillary acidic protein [GFAP]), correlated with risk factors for fetal death and placental histopathology. Methods This retrospective, observational cohort study included intrauterine deaths with transabdominal amniocentesis prior to induction of labor. Women with a normal pregnancy and an indicated amniocentesis at term were randomly selected as controls. AF was assayed for EPO, cTnI and GFAP using commercial immunoassays. Placental histopathology was reviewed, and CD15-immunohistochemistry was used. Analyte concentrations >90th centile for controls were considered "raised". Raised AF EPO, AF cTnI and AF GFAP concentrations were considered evidence of hypoxia, myocardial and brain injury, respectively. Results There were 60 cases and 60 controls. Hypoxia was present in 88% (53/60), myocardial damage in 70% (42/60) and brain injury in 45% (27/60) of fetal deaths. Hypoxic fetuses had evidence of myocardial injury, brain injury or both in 77% (41/53), 49% (26/53) and 13% (7/53) of cases, respectively. Histopathological evidence for placental dysfunction was found in 74% (43/58) of these cases. Conclusion Hypoxia, secondary to placental dysfunction, was found to be the mechanism of death in the majority of fetal deaths among structurally normal fetuses. Ninety-one percent of hypoxic fetal deaths sustained brain, myocardial or both brain and myocardial injuries in utero. Hypoxic myocardial injury was an attributable mechanism of death in 70% of the cases. Non-hypoxic cases may be caused by cardiac arrhythmia secondary to a cardiac conduction defect.

Evaluation of soluble TNF-like weak inducer of apoptosis (sTWEAK) levels to predict preeclampsia in early weeks of pregnancy

INTRODUCTION

Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) is linked to endothelial dysfunction; a key factor in pre-eclamptic pathogenesis. This study aimed to compare sTWEAK levels during pregnancy to assess for its prognostic ability.

MATERIALS AND METHODS

Sixty three high risk pregnant women were followed up from 12 weeks of gestation till term. Serum levels of sTWEAK and platelet derived growth factor (PlGF), blood pressure, serum glucose, uric acid, urea/creatinine and liver function tests were measured. Subjects were stratified according to the ACOG criteria as women who developed PE, or PIH or remained normotensive at term. A negative control group of normotensive healthy pregnant women (n = 17) was also recruited for comparison.

RESULTS

Baseline sTWEAK levels were lower (4.03 ± 0.37 ng/dl) in HR cohort that developed PE and further reduced at term (1.93 ± 0.23 ng/dl) as compared to HR subjects who remained normotensive and negative control group (30.53 ± 0.79 ng/dl; p < 0.01). Likewise PlGF levels were significantly lower (74.22 ± 10.11 pg/ml) in HR cohort that developed PE (p = 0.013). At term 39.68% (n = 22) HR subjects with low sTWEAK developed PIH and 34.92% (n = 24) developed PE. In terms of high risk characteristics observed in the HR group; 73% of the subjects were multiparous, whereas 26.98% reported to have developed PE in previous pregnancies.

CONCLUSION

sTWEAK levels at early pregnancy weeks were found to be low in high risk females who developed PE at follow up versus normotensive pregnant women. Baseline TWEAK might serve as an independent variable for prediction of pre-eclampsia; however longitudinal studies with larger sample size are required to ascertain the causal relation.

Extracellular vesicles generated by placental tissues ex vivo: A transport system for immune mediators and growth factors

PROBLEM

To study the mechanisms of placenta function and the role of extracellular vesicles (EVs) in pregnancy, it is necessary to develop an ex vivo system that retains placental cytoarchitecture and the primary metabolic aspects, in particular the release of EVs and soluble factors. Here, we developed such a system and investigated the pattern of secretion of cytokines, growth factors, and extracellular vesicles by placental villous and amnion tissues ex vivo.

METHODS OF STUDY

Placental villous and amnion explants were cultured for 2 weeks at the air/liquid interface and their morphology and the released cytokines and EVs were analyzed. Cytokines were analyzed with multiplexed bead assays, and individual EVs were analyzed with recently developed techniques that involved EV capture with magnetic nanoparticles coupled to anti-EV antibodies and flow cytometry.

RESULTS

Ex vivo tissues (i) remained viable and preserved their cytoarchitecture; (ii) maintained secretion of cytokines and growth factors; (iii) released EVs of syncytiotrophoblast and amnion epithelial cell origins that contain cytokines and growth factors.

CONCLUSION

A system of ex vivo placental villous and amnion tissues can be used as an adequate model to study placenta metabolic activity in normal and complicated pregnancies, in particular to characterize EVs by their surface markers and by encapsulated proteins. Establishment and benchmarking the placenta ex vivo system may provide new insight in the functional status of this organ in various placental disorders, particularly regarding the release of EVs and cytokines. Such EVs may have a prognostic value for pregnancy complications.

The prediction of fetal death with a simple maternal blood test at 20-24 weeks: a role for angiogenic index-1 (PlGF/sVEGFR-1 ratio)

BACKGROUND

Fetal death is an obstetrical syndrome that annually affects 2.4 to 3 million pregnancies worldwide, including more than 20,000 in the United States each year. Currently, there is no test available to identify patients at risk for this pregnancy complication.

OBJECTIVE

We sought to determine if maternal plasma concentrations of angiogenic and antiangiogenic factors measured at 24-28 weeks of gestation can predict subsequent fetal death.

STUDY DESIGN

A case-cohort study was designed to include 1000 randomly selected subjects and all remaining fetal deaths (cases) from a cohort of 4006 women with a singleton pregnancy, enrolled at 6-22 weeks of gestation, in a pregnancy biomarker cohort study. The placentas of all fetal deaths were histologically examined by pathologists who used a standardized protocol and were blinded to patient outcomes. Placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor-1 concentrations were measured by enzyme-linked immunosorbent assays. Quantiles of the analyte concentrations (or concentration ratios) were estimated as a function of gestational age among women who delivered a live neonate but did not develop preeclampsia or deliver a small-for-gestational-age newborn. A positive test was defined as analyte concentrations (or ratios) <2.5th and 10th centiles (placental growth factor, placental growth factor/soluble vascular endothelial growth factor receptor-1 [angiogenic index-1] and placental growth factor/soluble endoglin) or >90th and 97.5th centiles (soluble vascular endothelial growth factor receptor-1 and soluble endoglin). Inverse probability weighting was used to reflect the parent cohort when estimating the relative risk.

RESULTS

There were 11 fetal deaths and 829 controls with samples available for analysis between 24-28 weeks of gestation. Three fetal deaths occurred <28 weeks and 8 occurred ≥28 weeks of gestation. The rate of placental lesions consistent with maternal vascular underperfusion was 33.3% (1/3) among those who had a fetal death <28 weeks and 87.5% (7/8) of those who had this complication ≥28 weeks of gestation. The maternal plasma angiogenic index-1 value was <10th centile in 63.6% (7/11) of the fetal death group and in 11.1% (92/829) of the controls. The angiogenic index-1 value was <2.5th centile in 54.5% (6/11) of the fetal death group and in 3.7% (31/829) of the controls. An angiogenic index-1 value <2.5th centile had the largest positive likelihood ratio for predicting fetal death >24 weeks (14.6; 95% confidence interval, 7.7-27.7) and a relative risk of 29.1 (95% confidence interval, 8.8-97.1), followed by soluble endoglin >97.5th centile and placental growth factor/soluble endoglin <2.5th, both with a positive likelihood ratio of 13.7 (95% confidence interval, 7.3-25.8) and a relative risk of 27.4 (95% confidence interval, 8.2-91.2). Among women without a fetal death whose plasma angiogenic index-1 concentration ratio was <2.5th centile, 61% (19/31) developed preeclampsia or delivered a small-for-gestational-age neonate; when the 10th centile was used as the cut-off, 37% (34/92) of women had these adverse outcomes.

CONCLUSION

(1) A maternal plasma angiogenic index-1 value <2.5th centile (0.126) at 24-28 weeks of gestation carries a 29-fold increase in the risk of subsequent fetal death and identifies 55% of subsequent fetal deaths with a false-positive rate of 3.5%; and (2) 61% of women who have a false-positive test result will subsequently experience adverse pregnancy outcomes.

Birth weight to placenta weight ratio and its relationship to ultrasonic measurements, maternal and neonatal morbidity: A prospective cohort study of nulliparous women

INTRODUCTION

Birth weight to placenta weight (BWPW)-ratio is an indicator of the ability of the placenta to maintain adequate nutrient supply to the fetus. We sought to investigate the relationship between BWPW-ratio with fetal growth, utero-placental Doppler and neonatal and maternal morbidity.

METHODS

We studied a group of 3311 women recruited to a prospective cohort study of nulliparous women (Rosie Hospital, Cambridge, UK) who delivered a live born infant at term and whose placental weight and birth weight were known. Ultrasonic indices and BWPW ratio were converted to gestational age adjusted z scores. Analysis of continuous variables was by multivariable linear regression. BWPW ratio was also categorized (lowest or highest quintile, both referent to quintiles 2 to 4) and associations with adverse outcomes analyzed using multivariable logistic regression.

RESULTS

Lowest quintile of BWPW-ratio was associated (adjusted odds ratio [95% CI], P) with both neonatal morbidity (1.55 [1.12-2.14], 0.007) and maternal diabetes (1.75 [1.18-2.59], 0.005). Highest quintile of BWPW ratio was associated with a reduced risk of maternal obesity (0.71 [0.53 to 0.95], 0.02) and preeclampsia (0.51 [0.31 to 0.84], 0.008), but higher (adjusted z score [95% CI], P) uterine artery Doppler mean pulsatility index (PI) at 20 weeks of gestation (0.09 [0.01-0.18], 0.04) and umbilical artery Doppler PI at 36 weeks of gestation (0.16 [0.07-0.25], <0.001).

CONCLUSION

BWPW-ratio is related to ultrasonic measurements and both neonatal and maternal morbidity. Therefore, this ratio may be an indicative marker of immediate and longer term health risks for an individual.

An investigation of fetal behavioural states during maternal sleep in healthy late gestation pregnancy: an observational study

KEY POINTS

Fetal behavioural state in healthy late gestation pregnancy is significantly affected by maternal position overnight. Maternal left lateral position is the one most frequently adopted at sleep onset. The maternal position at sleep onset is maintained the longest overnight. Fetal state 1F is more common in maternal supine positions overnight. Fetal state 4F is less common in maternal supine sleep positions. Fetal state and maternal sleep position are independently associated with fetal heart rate variability. Maternal sleep position significantly affects fetal heart rate and heart rate variability and affects circadian fetal heart rate patterns.

ABSTRACT

Fetal behavioural states (FBS) are measures of fetal wellbeing. Maternal position affects FBS with supine position being associated with an increased likelihood of fetal quiescence consistent with the human fetus adapting to a lower oxygen consuming state. Several studies have now confirmed the association between sleep position and risk of late intrauterine death. We designed this study to observe the effects of maternal sleep positions overnight in healthy late gestation pregnancy. Twenty-nine healthy women had continuous fetal ECG recordings overnight. Two blinded observers assigned fetal states in 5 min blocks. Measures of fetal heart rate variability (FHRV) were calculated from ECG beat to beat data. Maternal position was determined from infrared video recording. Compared to state 2F (active sleep), 4F (active awake-high activity) occurred almost exclusively when the mother was in a left or right lateral position. State 1F (quiet sleep) was more common when the mother was supine [odds ratio (OR) 1.30, 95% confidence interval (CI) 1.11-1.52] and less common on the maternal right side with the left being the referent position (OR 0.81, 95% CI, 0.70-0.93). State 4F was more common between 21.00 and 01.00 h than between 01.00 and 07.00 h (OR 2.83, 95% CI 2.32-3.47). In each fetal state, maternal position had significant effects on fetal heart rate and measures of FHRV. In healthy late gestation pregnancy, maternal sleep position affects FBS and heart rate variability. These effects are probably fetal adaptations to positions which may produce a mild hypoxic stress.

Placental histopathology associated with pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

Pre-eclampsia (PE) is associated with impaired trophoblastic invasion and typical villous and vascular placental lesions. The primary aim of this study was to quantify the prevalence of placental histopathological lesions in pregnancies complicated by PE.

METHODS

MEDLINE, EMBASE and CINAHL were searched electronically, and relevant articles reporting on placental histopathological lesions were assessed according to the following criteria: study design, number of pregnancies included, severity of PE and whether the pathologist was blinded to the clinical information. Prospective and retrospective case-control studies including ≥ 100 pregnancies were included in the systematic review. The incidence of each type of histological lesion according to the Perinatal Section of the Society for Pediatric Pathology classification in pre-eclamptic and normal pregnancies was identified, and lesions were categorized into two main groups: villous lesions and vascular lesions. Random-effects meta-analysis of proportions was used for analysis. Between-study heterogeneity was assessed using the I² statistic.

RESULTS

The search yielded 717 citations, and a total of eight studies (four blinded and four non-blinded) were included in the review. In unblinded studies, the pooled prevalence of villous lesions was 11.6% and 48.2% in normal and pre-eclamptic pregnancies, respectively, giving a pooled odds ratio (OR) of 7.59. In blinded studies, the pooled prevalence of villous lesions was 18.5% and 42.0% in normal and pre-eclamptic pregnancies, respectively, giving a pooled OR of 4.28. In unblinded studies, the pooled prevalence of vascular lesions was 8.1% and 37.3% in normal and pre-eclamptic pregnancies, respectively, giving a pooled OR of 20.34. In blinded studies, the pooled prevalence of vascular lesions was 9.8% and 38.9%, in normal and pre-eclamptic pregnancies, respectively, giving a pooled OR of 7.08.

CONCLUSIONS

In blinded studies, the incidence of both placental villous and vascular histopathological lesions is four- to seven-fold higher in pre-eclamptic than in normal pregnancies. Greater differences are reported in unblinded studies. Despite the higher probability (point prevalence) of finding abnormal placental pathology in pregnancies with PE, placental lesions are not specific to the diagnosis of PE. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Stillbirth and intrauterine fetal death: factors affecting determination of cause of death at autopsy

OBJECTIVES

There have been several attempts to classify cause of death (CoD) in stillbirth; however, all such systems are subjective, allowing for observer bias and making comparisons between systems challenging. This study aimed to examine factors relating to determination of CoD using a large dataset from two specialist centers in which observer bias had been reduced by classifying findings objectively and assigning CoD based on predetermined criteria.

METHODS

Detailed autopsy reports from intrauterine deaths in the second and third trimesters during 2005-2013 were reviewed and findings entered into a specially designed database, in which CoD was assigned using predefined objective criteria. Data regarding CoD categories and factors affecting determination of CoD were examined.

RESULTS

There were 1064 intrauterine deaths, including 246 early intrauterine fetal deaths (IUFD) (< 20 weeks), 179 late IUFDs (20-23 weeks) and 639 stillbirths (≥ 24 weeks' gestation). Overall, around 40% (n = 412) had a clear CoD identified, whilst around 60% (n = 652) were classified as 'unexplained', including around half with identified risk factors or lesions of uncertain significance, with the remaining half (n = 292 (45%)) being entirely unexplained. A stepwise increase in the proportion of unexplained deaths was observed with increasing maceration. Black and Asian women had significantly greater proportions of deaths due to ascending infection, whilst women aged over 40 years had significantly increased placenta-related CoDs. There was no significant difference in CoD distribution according to maternal body mass index or with increasing postmortem interval. Around half of those with an identifiable CoD could be identified from clinical review and external fetal examination or imaging, with most of the remainder being determined following placental examination.

CONCLUSIONS

Based on objective criteria, many intrauterine deaths throughout gestation remain unexplained despite autopsy examination. The rate of unexplained death varies from around 30% to 60% depending on interpretation of the significance of features. CoD determination is dependent on both the classification system used and subjective interpretation, such that variation in the proportion of 'unexplained' cases is based largely on speculation regarding mechanisms of death. Novel methods to determine objectively the mechanism of death at postmortem examination are required. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Organ weights and ratios for postmortem identification of fetal growth restriction: utility and confounding factors

OBJECTIVES

The postmortem fetal brain:liver weight ratio is commonly used as a marker of nutrition for diagnosis of fetal growth restriction (FGR). However, there are limited data regarding the effects of intrauterine retention, fetal maceration and postmortem interval on organ weights and their ratios at autopsy. Our aims were to examine the relationships between gestational-age-adjusted and sex-adjusted fetal organ weights at autopsy, cause of intrauterine death and effects of intrauterine retention, and to determine whether the brain:liver weight ratio is a reliable marker of FGR in intrauterine death.

METHODS

As part of a larger study examining autopsy findings in intrauterine death, data from two specialist centers in London were collated in a specially designed database. Autopsy and clinical information for > 1000 intrauterine deaths between 2005 and 2013 were extracted. Adjusted (delta) organ weights were calculated by plotting against gestational age female and male brain, liver, thymus, heart, combined kidney, combined lung, spleen and combined adrenal gland weights. Polynomial regression was used to determine best fit and to calculate expected (50^th centile) organ weights and deviations from expected. We compared adjusted organ weights and body:organ weight ratios in fetuses which were small-for-gestational age (SGA) at autopsy (birth weight < 10^th centile for normal live births) vs those in fetuses which were not, and in macerated vs non-macerated fetuses.

RESULTS

The majority of fetal organs (brain, liver, heart, thymus, lungs, kidneys and thyroid) in SGA fetuses were significantly lighter than those in non-SGA fetuses. Body:organ weight ratios for thymus, liver and spleen were significantly greater in SGA fetuses, indicating these organs to be disproportionately small. The majority of organs were significantly lighter in macerated compared with non-macerated fetuses and body:organ weight ratios for most organs (liver, thymus, lung, pancreas, adrenal gland, kidney, heart) were significantly greater in macerated compared with non-macerated fetuses. When SGA cases with demonstrable placental histological abnormalities were compared with other SGA cases, there was a significant difference in the brain:liver weight ratio (median, 6 vs 3.5).

CONCLUSION

Changes after intrauterine death lead to loss of fetal weight, with preferential weight loss of visceral organs such as the liver. Maceration therefore affects the brain:liver weight ratio and adjustment should be made for such changes during interpretation of ratios. Fetal organ weights may be affected significantly by mechanism of death and postmortem changes. The fetal brain:liver weight ratio may provide useful information regarding intrauterine growth status at time of death, provided that adjustment is made for effects of intrauterine retention and that appropriate cut-off values are used. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.