Stillbirth Collaborative Research Network: design, methods and recruitment experience

Short Term Coping-Behaviors and Postpartum Health in a Population-Based Study of Women with a Live Birth, Stillbirth, or Neonatal Death

OBJECTIVE

Responding to the National Institutes of Health Working Group's call for research on the psychological impact of stillbirth, we compared coping-related behaviors by outcome of an index birth (surviving live birth or perinatal loss - stillbirth or neonatal death) and, among individuals with loss, characterized coping strategies and their association with depressive symptoms 6-36 months postpartum.

METHODS

We used data from the Stillbirth Collaborative Research Network follow-up study (2006-2008) of 285 individuals who experienced a stillbirth, 691 a livebirth, and 49 a neonatal death. We conducted a thematic analysis of coping strategies individuals recommended following their loss. We fit logistic regression models, accounting for sampling and inverse probability of follow-up weights to estimate associations between pregnancy outcomes and coping-related behaviors and, separately, coping strategies and probable depression (Edinburgh Postnatal Depression Scale > 12) for those with loss.

RESULTS

Compared to those with a surviving live birth and adjusting for pre-pregnancy drinking and smoking, history of stillbirth, and age, individuals who experienced a loss were more likely to report increased drinking or smoking in the two months postpartum (adjusted OR: 2.7, 95% CI = 1.4-5.4). Those who smoked or drank more had greater odds of probable depression at 6 to 36 months postpartum (adjusted OR 6.4, 95% CI = 2.5-16.4). Among those with loss, recommended coping strategies commonly included communication, support groups, memorializing the loss, and spirituality.

DISCUSSION

Access to a variety of evidence-based and culturally-appropriate positive coping strategies may help individuals experiencing perinatal loss avoid adverse health consequences.

DLK1: A Novel Biomarker of Placental Insufficiency in Stillbirth and Live Birth

OBJECTIVE

 Delta-like homolog 1 (DLK1) is a growth factor that is reduced in maternal sera in pregnancies with small for gestational age neonates. We sought to determine if DLK1 is associated with stillbirth (SB), with and without placental insufficiency.

STUDY DESIGN

 A nested case-control study was performed using maternal sera from a multicenter case-control study of SB and live birth (LB). SB and LB were stratified as placental insufficiency cases (small for gestational age <5% or circulatory lesions on placental histopathology) or normal placenta controls (appropriate for gestational age and no circulatory lesions). Enzyme-linked immunosorbent assay (ELISA) was used to measure DLK1. The mean difference in DLK1 was compared on the log scale in an adjusted linear regression model with pairwise differences, stratified by term/preterm deliveries among DLK1 results in the quantifiable range. In exploratory analysis, geometric means were compared among all data and the proportion of "low DLK1" (less than the median value for gestational age) was compared between groups and modeled using linear and logistic regression, respectively.

RESULTS

 Overall, 234 SB and 234 LB were analyzed; 246 DLK1 values were quantifiable within the standard curve. Pairwise comparisons of case and control DLK1 geometric means showed no significant differences between groups. In exploratory analysis of all data, adjusted analysis revealed a significant difference for the LB comparison only (SB: 71.9 vs. 99.1 pg/mL, p = 0.097; LB: 37.6 vs. 98.1 pg/mL, p = 0.005). In exploratory analysis of "low DLK1," there was a significant difference between the odds ratio of having "low DLK1" between preterm cases and controls for both SB and LB. There were no significant differences in geometric means nor "low DLK1" between SB and LB.

CONCLUSION

 In exploratory analysis, more placental insufficiency cases in preterm SB and LB had "low DLK1." However, low DLK1 levels were not associated with SB.

KEY POINTS

· Maternally circulating DLK1 is correlated with placental insufficiency.. · Maternally circulating DLK1 is not correlated with SB.. · DLK1 is a promising marker for placental insufficiency..

Racial and ethnic inequities in stillbirth in the US: Looking upstream to close the gap: Seminars in Perinatology

Though stillbirth rates in the United States improved over the previous decades, inequities in stillbirth by race and ethnicity have persisted nearly unchanged since data collection began. Black and Indigenous pregnant people face a two-fold greater risk of experiencing the devastating consequences of stillbirth compared to their White counterparts. Because race is a social rather than biological construct, inequities in stillbirth rates are a downstream consequence of structural, institutional, and interpersonal racism which shape a landscape of differential access to opportunities for health. These downstream consequences can include differences in the prevalence of chronic health conditions as well as structural differences in the quality of health care or healthy neighborhood conditions, each of which likely plays a role in racial and ethnic inequities in stillbirth. Research and intervention approaches that utilize an equity lens may identify ways to close gaps in stillbirth incidence or in responding to the health and socioemotional consequences of stillbirth. A community-engaged approach that incorporates experiential wisdom will be necessary to create a full picture of the causes and consequences of inequity in stillbirth outcomes. Investigators working in tandem with community partners, utilizing a combination of qualitative, quantitative, and implementation science approaches, may more fully elucidate the underpinnings of racial and ethnic inequities in stillbirth outcomes.

Copy number variants and fetal structural abnormalities in stillborn fetuses: A secondary analysis of the Stillbirth Collaborative Research Network study

OBJECTIVE

To examine the association of placental and fetal DNA copy number variants (CNVs) with fetal structural malformations (FSMs) in stillborn fetuses.

DESIGN

A secondary analysis of stillbirth cases in the Stillbirth Collaborative Research Network (SCRN) study.

SETTING

Multicenter, 59 hospitals in five geographic regions in the USA.

POPULATION

388 stillbirth cases of the SCRN study (2006-2008).

METHODS

Fetal structural malformations were grouped by anatomic system and specific malformation type (e.g. central nervous system, thoracic, cardiac, gastrointestinal, skeletal, umbilical cord and craniofacial defects). Single-nucleotide polymorphism array detected CNVs of at least 500 kb. CNVs were classified into two groups: normal, defined as no CNVs >500 kb or benign CNVs, and abnormal, defined as pathogenic or variants of unknown clinical significance.

MAIN OUTCOME MEASURES

The proportions of abnormal CNVs and normal CNVs were compared between stillbirth cases with and without FSMs using the Wald Chi-square test.

RESULTS

The proportion of stillbirth cases with any FSMs was higher among those with abnormal CNVs than among those with normal CNVs (47.5 versus 19.1%; P-value <0.001). The most common organ system-specific FSMs associated with abnormal CNVs were cardiac defects, followed by hydrops, craniofacial defects and skeletal defects. A pathogenic deletion of 1q21.1 involving 46 genes (e.g. CHD1L) and a duplication of 21q22.13 involving four genes (SIM2, CLDN14, CHAF1B, HLCS) were associated with a skeletal and cardiac defect, respectively.

CONCLUSION

Specific CNVs involving several genes were associated with FSMs in stillborn fetuses. The findings warrant further investigation and may inform counselling and care surrounding pregnancies affected by FSMs at risk for stillbirth.

Placental Lesions Associated With Stillbirth by Gestational Age, as Related to Cause of Death: Follow-Up Results From the Stillbirth Collaborative Research Network

BACKGROUND

We previously identified placental lesions associated with stillbirths of varying gestational ages (GA) using advanced feature analysis. We further investigated the relationships between placental lesions and cause of death in stillbirths within these GA ranges.

METHODS

Using data from the Stillbirth Collaborative Research Network, we derived a sample of stillbirths who underwent placental examination and Initial Causes of Fetal Death (INCODE) evaluation for determining cause of death. We then compared the rates of causes of death within and among GA ranges (extreme preterm stillbirth [PTSB] [<28 weeks], early PTSB [28-336/7 weeks], late PTSB [34-366/7 weeks], term stillbirth [≥37 weeks]) according to the presence of these lesions.

RESULTS

We evaluated 352 stillbirths. In extreme PTSB, obstetric complications and infections were associated with acute funisitis. In early PTSB, uteroplacental insufficiency was associated with parenchymal infarcts. In term stillbirth (vs early PTSB), increased syncytial knots were associated with umbilical cord causes and infection.

CONCLUSIONS

Placental lesions of high importance in distinguishing stillbirths at different GAs are associated with specific causes of death. This information is important in relating the presence of placental lesions and fetal death and in helping to understand etiologies of stillbirths at different GAs.

Assessing Intrauterine Retention according to Microscopic Stillbirth Features: A Cluster Analysis Approach

Background: Previous studies identified microscopic changes associated with intrauterine retention of stillbirths based on clinical time of death. The objective of this study was to utilize unsupervised machine learning (not reliant on subjective measures) to identify features associated with time from death to delivery. Methods: Data were derived from the Stillbirth Collaborative Research Network. Features were chosen a priori for entry into hierarchical cluster analysis, including fetal and placental changes. Results: A four-cluster solution (coefficient = 0.983) correlated with relative time periods of "no retention," "mild retention," "moderate retention," and "severe retention." Loss of nuclear basophilia within fetal organs were found at varying rates among these clusters. Conclusions: Hierarchical cluster analysis is able to classify stillbirths based on histopathological changes, roughly correlating to length of intrauterine retention. Such clusters, which rely solely on objective fetal and placental findings, can help clinicians more accurately assess the interval from death to delivery.

Perinatal health effects of herbicides exposures in the United States: the Heartland Study, a Midwestern birth cohort study

BACKGROUND

The objective of the Heartland Study is to address major knowledge gaps concerning the health effects of herbicides on maternal and infant health. To achieve this goal, a two-phased, prospective longitudinal cohort study is being conducted. Phase 1 is designed to evaluate associations between biomarkers of herbicide concentration and pregnancy/childbirth outcomes. Phase 2 is designed to evaluate potential associations between herbicide biomarkers and early childhood neurological development.

METHODS

People (target enrollment of 2,000) who are seeking prenatal care, are ages 18 or older, and are ≤ 20 + 6 weeks gestation will be eligible for recruitment. The Heartland Study will utilize a combination of questionnaire data and biospecimen collections to meet the study objectives. One prenatal urine and buccal sample will be collected per trimester to assess the impact of herbicide concentration levels on pregnancy outcomes. Infant buccal specimens will be collected post-delivery. All questionnaires will be collected by trained study staff and clinic staff will remain blinded to all individual level research data. All data will be stored in a secure REDCap database. Hospitals in the agriculturally intensive states in the Midwestern region will be recruited as study sites. Currently participating clinical sites include Indiana University School of Medicine- affiliated Hospitals in Indianapolis, Indiana; Franciscan Health Center in Indianapolis, Indiana; Gundersen Lutheran Medical Center in La Crosse, Wisconsin, and University of Iowa in Iowa City, Iowa. An anticipated 30% of the total enrollment will be recruited from rural areas to evaluate herbicide concentrations among those pregnant people residing in the rural Midwest. Perinatal outcomes (e.g. birth outcomes, preterm birth, preeclampsia, etc.) will be extracted by trained study teams and analyzed for their relationship to herbicide concentration levels using appropriate multivariable models.

DISCUSSION

Though decades of study have shown that environmental chemicals may have important impacts on the health of parents and infants, there is a paucity of prospective longitudinal data on reproductive impacts of herbicides. The recent, rapid increases in herbicide use across agricultural regions of the United States necessitate further research into the human health effects of these chemicals, particularly in pregnant people. The Heartland Study provides an invaluable opportunity to evaluate health impacts of herbicides during pregnancy and beyond.

TRIAL REGISTRATION

The study is registered at clinicaltrials.gov, NCT05492708 with initial registration and release 05 August, 2022.

Data usefulness in determining cause of stillbirth in South Asia

OBJECTIVE

To evaluate the usefulness of data to determine cause of stillbirth in India and Pakistan.

DESIGN

Prospective, observational study.

SETTINGS

Study hospitals in India and Pakistan.

POPULATION

200 fetal deaths with placental evaluation and minimally invasive tissue sampling (MITS) of internal organs and polymerase chain reaction (PCR) test for 75 pathogens.

MAIN OUTCOME MEASURES

Data defined as useful to determine stillbirth causes.

RESULTS

Placental pathology was the most useful to determine cause of stillbirth. Comparing placental and fetal weight with standard weights was useful in 44.5% and 48.5%, respectively. Lung histology was useful in 42.5%. Most of the other findings of internal organ histology were only occasionally useful. Signs of abruption, by maternal history or placental evaluation, were always deemed useful. Placenta, brain and cord blood PCR were also useful, but less often than histology.

CONCLUSION

Based on this analysis, maternal clinical history, placental histology and fetal examination were most informative. Comparing the placental and fetal weights with recognised standards was useful in nearly half the cases. Fetal tissue histology and PCR were also informative. Of all the potential tests of MITS-obtained specimens, we would first recommend histological evaluation of the lungs, and using a multiplex PCR platform would determine pathogens in blood and brain/CSF. We recognise that this approach will not identify some causes, including some genetic and internal organ anomalies, but will confirm most common causes of stillbirth and most of the preventable causes of stillbirth in low- and middle-income countries.

Regulatory T cell adoptive transfer alters uterine immune populations, increasing a novel MHC-IIlow macrophage associated with healthy pregnancy

Intrauterine fetal demise (IUFD) - fetal loss after 20 weeks - affects 6 pregnancies per 1,000 live births in the United States, and the majority are of unknown etiology. Maternal systemic regulatory T cell (Treg) deficits have been implicated in fetal loss, but whether mucosal immune cells at the maternal-fetal interface contribute to fetal loss is under-explored. We hypothesized that the immune cell composition and function of the uterine mucosa would contribute to the pathogenesis of IUFD. To investigate local immune mechanisms of IUFD, we used the CBA mouse strain, which naturally has mid-late gestation fetal loss. We performed a Treg adoptive transfer and interrogated both pregnancy outcomes and the impact of systemic maternal Tregs on mucosal immune populations at the maternal-fetal interface. Treg transfer prevented fetal loss and increased an MHC-IIlow population of uterine macrophages. Single-cell RNA-sequencing was utilized to precisely evaluate the impact of systemic Tregs on uterine myeloid populations. A population of C1q+, Trem2+, MHC-IIlow uterine macrophages were increased in Treg-recipient mice. The transcriptional signature of this novel uterine macrophage subtype is enriched in multiple studies of human healthy decidual macrophages, suggesting a conserved role for these macrophages in preventing fetal loss.

Macroscopic lesions of maternal and fetal vascular malperfusion in stillborn placentas: Diagnosis in the absence of microscopic histopathological examination

INTRODUCTION

Lesions of maternal vascular malperfusion (MVM) and fetal vascular malperfusion (FVM) are common in placentas associated with both stillbirth and live birth. The objective of this study was to identify lesions present more commonly in stillborn placentas and those most indicative of MVM and FVM without microscopic pathologic evaluation.

METHODS

Data were derived from the Stillbirth Collaborative Research Network. Lesions were identified according to standard protocols published previously and categorized as either MVM or FVM according to the Amsterdam Placental Workshop Group Consensus Statement and macroscopic "umbilical cord at risk" findings. Multivariate logistic regression was used to determine the odds of stillbirth with macroscopic findings of MVM or FVM.

RESULTS

595 stillbirths and 1,305 live births were analyzed. FVM lesions (85.2%) were marginally more common (though not statistically different) in stillbirths compared to MVM lesions (81.3%). Macroscopic findings of both MVM and FVM were more common in stillbirths versus livebirths (p < 0.001). Odds ratios of macroscopic MVM and FVM lesions for stillbirth, adjusted for gestational age at delivery, maternal race (minority), ethnicity (Hispanic), age, and history of hypertension or diabetes, were 1.48 (95% CI 1.30-1.69) and 1.34 (95% CI 1.18-1.53), respectively.

DISCUSSION

Macroscopic features of MVM and FVM are associated with higher odds of stillbirth versus live birth even when controlled for gestational age and maternal factors, which may be a useful clue in determining the pathophysiology of these events. This information is also useful for pathologists when microscopic examination is not available.

Identifying risk of stillbirth using machine learning

BACKGROUND

Previous predictive models using logistic regression for stillbirth do not leverage the advanced and nuanced techniques involved in sophisticated machine learning methods, such as modeling nonlinear relationships between outcomes.

OBJECTIVE

This study aimed to create and refine machine learning models for predicting stillbirth using data available before viability (22-24 weeks) and throughout pregnancy, as well as demographic, medical, and prenatal visit data, including ultrasound and fetal genetics.

STUDY DESIGN

This is a secondary analysis of the Stillbirth Collaborative Research Network, which included data from pregnancies resulting in stillborn and live-born infants delivered at 59 hospitals in 5 diverse regions across the United States from 2006 to 2009. The primary aim was the creation of a model for predicting stillbirth using data available before viability. Secondary aims included refining models with variables available throughout pregnancy and determining variable importance.

RESULTS

Among 3000 live births and 982 stillbirths, 101 variables of interest were identified. Of the models incorporating data available before viability, the random forests model had 85.1% accuracy (area under the curve) and high sensitivity (88.6%), specificity (85.3%), positive predictive value (85.3%), and negative predictive value (84.8%). A random forests model using data collected throughout pregnancy resulted in accuracy of 85.0%; this model had 92.2% sensitivity, 77.9% specificity, 84.7% positive predictive value, and 88.3% negative predictive value. Important variables in the previability model included previous stillbirth, minority race, gestational age at the earliest prenatal visit and ultrasound, and second-trimester serum screening.

CONCLUSION

Applying advanced machine learning techniques to a comprehensive database of stillbirths and live births with unique and clinically relevant variables resulted in an algorithm that could accurately identify 85% of pregnancies that would result in stillbirth, before they reached viability. Once validated in representative databases reflective of the US birthing population and then prospectively, these models may provide effective risk stratification and clinical decision-making support to better identify and monitor those at risk of stillbirth.

Placental lesions associated with stillbirth by gestational age, according to feature importance: Results from the stillbirth collaborative research network

INTRODUCTION

Previous studies have identified lesions commonly found in placentas associated with stillbirth but have not distinguished across a range of gestational ages (GAs). The objective of this study was to identify lesions associated with stillbirths at different GAs by adapting methods from the chemical machine learning field to assign lesion importance based on correlation with GA.

METHODS

Placentas from the Stillbirth Collaborative Research Network were examined according to standard protocols. GAs at stillbirth were categorized as: <28 weeks (extreme preterm stillbirth [PTSB]), 28-33'6 weeks (early PTSB), 34-36'6 weeks (late PTSB), ≥37 weeks (term stillbirth). We identified and ranked the most discriminating placental features, as well as those that were similar across GA ranges, using Kernel Principal Covariates Regression (KPCovR).

RESULTS

These analyses included 210 (47.2%) extreme PTSB, 85 (19.1%) early PTSB, 62 (13.9%) late PTSB, and 88 (19.8%) term stillbirths. When we compute the KPCovR, the first principal covariate indicates that there are four lesions (acute funisitis & nucleated fetal red blood cells found in extreme PTSB; multifocal reactive amniocytes & multifocal meconium found in term stillbirth) that distinguish GA ranges among all stillbirths.

DISCUSSION

There are distinct placental lesions present across GA ranges in stillbirths; these lesions are identifiable using sophisticated feature selection. Further investigation may identify histologic changes across gestations that relate to fetal mortality.

Copy number variants and fetal growth in stillbirths

BACKGROUND

Fetal growth abnormalities are associated with a higher incidence of stillbirth, with small and large for gestational age infants incurring a 3 to 4- and 2 to 3-fold increased risk, respectively. Although clinical risk factors such as diabetes, hypertension, and placental insufficiency have been associated with fetal growth aberrations and stillbirth, the role of underlying genetic etiologies remains uncertain.

OBJECTIVE

This study aimed to assess the relationship between abnormal copy number variants and fetal growth abnormalities in stillbirths using chromosomal microarray.

STUDY DESIGN

A secondary analysis utilizing a cohort study design of stillbirths from the Stillbirth Collaborative Research Network was performed. Exposure was defined as abnormal copy number variants including aneuploidies, pathogenic copy number variants, and variants of unknown clinical significance. The outcomes were small for gestational age and large for gestational age stillbirths, defined as a birthweight <10th percentile and greater than the 90th percentile for gestational age, respectively.

RESULTS

Among 393 stillbirths with chromosomal microarray and birthweight data, 16% had abnormal copy number variants. The small for gestational age outcome was more common among those with abnormal copy number variants than those with a normal microarray (29.5% vs 16.5%; P=.038). This finding was consistent after adjusting for clinically important variables. In the final model, only abnormal copy number variants and maternal age remained significantly associated with small for gestational age stillbirths, with an adjusted odds ratio of 2.22 (95% confidence interval, 1.12-4.18). Although large for gestational age stillbirths were more likely to have an abnormal microarray: 6.2% vs 3.3% (P=.275), with an odds ratio of 2.35 (95% confidence interval, 0.70-7.90), this finding did not reach statistical significance.

CONCLUSION

Genetic abnormalities are more common in the setting of small for gestational age stillborn fetuses. Abnormal copy number variants not detectable by traditional karyotype make up approximately 50% of the genetic abnormalities in this population.

Copy number variants and placental abnormalities in stillborn fetuses: A secondary analysis of the Stillbirth Collaborative Research Network study

OBJECTIVE

To examine the association of fetal/placental DNA copy number variants (CNVs) with pathologic placental lesions (PPLs) in pregnancies complicated by stillbirth.

DESIGN

A secondary analysis of stillbirth cases in the Stillbirth Collaborative Research Network case-control study.

SETTING

Multicenter, 59 hospitals in five geographical regions in the USA.

POPULATION

387 stillbirth cases (2006-2008).

METHODS

Using standard definitions, PPLs were categorised by type including maternal vascular, fetal vascular, inflammatory and immune/idiopathic lesions. Single-nucleotide polymorphism array detected CNVs of at least 500 kb. CNVs were classified into two groups: normal, defined as no CNV >500 kb or benign CNVs, and abnormal, defined as pathogenic or variants of unknown clinical significance.

MAIN OUTCOME MEASURES

The proportions of abnormal CNVs and normal CNVs compared between stillbirth cases with and without PPLs using the Wald Chi-square test.

RESULTS

Of 387 stillborn fetuses, 327 (84.5%) had maternal vascular PPLs and 60 (15.6%) had abnormal CNVs. Maternal vascular PPLs were more common in stillborn fetuses with abnormal CNVs than in those with normal CNVs (81.7% versus 64.2%; P = 0.008). The proportions of fetal vascular, maternal/fetal inflammatory and immune/idiopathic PPLs were similar among stillborn fetuses with abnormal CNVs and those with normal CNVs. Pathogenic CNVs in stillborn fetuses with maternal vascular PPLs spanned several known genes.

CONCLUSIONS

Abnormal placental/fetal CNVs were associated with maternal vascular PPLs in stillbirth cases. The findings may provide insight into the mechanisms of specific genetic abnormalities associated with placental dysfunction and stillbirth.

Microbial Analysis of Umbilical Cord Blood Reveals Novel Pathogens Associated with Stillbirth and Early Preterm Birth

Stillbirths account for half of all perinatal mortality, but the underlying cause of a significant portion of the cases remains unknown. We set out to test the potential role and extent of microbial infection in stillbirth through a case-control analysis of fetal cord blood collected from the multisite Stillbirth Collaborative Research Network. Cases (n = 60) were defined as stillbirths at >20 weeks of gestation, and controls (n = 176) were live births. The bacterial presence, abundance, and composition were analyzed by endpoint PCR of full-length 16S rRNA and the V4 amplicon sequence variants (ASVs). The results demonstrate that bacterial prevalence and abundance were both significantly increased in stillbirth, even after adjusting for maternal age, race, body mass index, number of pregnancies, gestational age, and multiple gestations. Composition of bacterial communities in the cord blood also differed significantly. Using a group of 25 ASVs differentially abundant between the two groups, a Random Forest classification model achieved an accuracy score of 0.76 differentiating stillbirth and live birth, with Group B Streptococcus as the most enriched species in stillbirth. Positive PCR was also significantly associated with early preterm birth. A group of oral anaerobes, including Actinomyces, Campylobacter, Fusobacterium, Peptostreptococcus, Porphyromonas, and Prevotella, were enriched in live early preterm birth, suggesting possible oral origin of infection. Our ASV-based microbiome analysis revealed specific candidate pathogens associated with infections in stillbirth and early preterm birth. The cord blood microbial signatures may be markers of adverse pregnancy outcomes. Our study will help identify possible mechanism of infection and improve our ability to prevent stillbirth and early preterm birth.

Holding a baby after stillbirth: the impact of fetal congenital and structural abnormalities

OBJECTIVE

Stillbirth can result in numerous adverse psychosocial sequelae. Recommendations vary with regard to holding the baby after a stillbirth. Few studies have addressed the impact of fetal abnormalities on these outcomes.

STUDY DESIGN

Analyses of singleton stillbirths within the Stillbirth Collaborative Research Network were conducted. Patient and stillbirth characteristics were compared between those who did and did not hold their baby. Results from psychometric surveys were compared between cases with and without visible fetal anomalies.

RESULT

There were no significant differences between those who held and those who did not hold in any patient or stillborn characteristics. Visible fetal abnormalities were not associated with adverse psychological outcomes.

CONCLUSION

Fetal abnormalities, including congenital and post-demise changes, do not differ between those who held and did not hold their baby after stillbirth. This suggests that patients should not be discouraged from holding their stillborn infant in the presence of visible abnormalities.

Maternal Marijuana Exposure, Feto-Placental Weight Ratio, and Placental Histology

OBJECTIVE

Marijuana use is associated with placenta-mediated adverse pregnancy outcomes including fetal growth restriction, but the mechanism remains uncertain. The objective was to evaluate the association between maternal marijuana use and the feto-placental weight ratio (FPR). Secondarily, we aimed to compare placental histology of women who used marijuana to those who did not.

STUDY DESIGN

This was a secondary analysis of singleton pregnancies enrolled in a multicenter and case-control stillbirth study. Prior marijuana use was detected by electronic medical record abstraction or cord homogenate positive for 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid. Prior tobacco use was detected by self-report or presence of maternal serum cotinine. Stillbirths and live births were considered separately. The primary outcome was FPR. Association of marijuana use with FPR was estimated with multivariable linear modeling adjusted for fetal sex, preterm birth, and tobacco use. Comparisons between groups for placental histology were made using Chi-square and stratified by live birth and stillbirth, term and preterm deliveries, and fetal sex.

RESULTS

Of 1,027 participants, 224 were stillbirths and 803 were live births. Overall, 41 (4%) women used marijuana during the pregnancy. The FPR ratio was lower among exposed offspring but reached statistical significance only for term stillbirths (mean 6.84 with marijuana use vs. mean 7.8 without use, p < 0.001). In multivariable modeling, marijuana use was not significantly associated with FPR (p = 0.09). There were no differences in histologic placental features among those with and without marijuana use overall or in stratified analyses.

CONCLUSION

Exposure to marijuana may not be associated with FPR. Similarly, there were no placental histologic features associated with marijuana exposure. Further study of the influence of maternal marijuana use on placental development and function is warranted to better understand the association between prenatal marijuana use and poor fetal growth.

KEY POINTS

· Maternal marijuana exposure was not associated with the feto-placental weight ratio.. · Marijuana exposure was not associated with differences in placental histology.. · Concerning trend toward lower feto-placental weight ratios among marijuana-exposed stillbirths..

Preeclampsia at delivery is associated with lower serum vitamin D and higher antiangiogenic factors: a case control study

BACKGROUND

Preeclampsia is characterized by decreased trophoblastic angiogenesis leading to abnormal invasion of spiral arteries, shallow implantation and resulting in compromised placentation with poor uteroplacental perfusion. Vitamin D plays an important role in pregnancy influencing implantation, angiogenesis and placental development. The objective of this study was to determine whether there is an association between serum vitamin D levels, and anti-angiogenic factors at the time of delivery and the occurrence of preeclampsia.

METHODS

This nested case control study analyzed frozen serum samples at the time of delivery and related clinical data from women with singleton liveborn pregnancies who had participated in studies of the NICHD Stillbirth Collaborative Research Network. Women with a recorded finding of preeclampsia and who had received magnesium sulfate treatment prior to delivery were considered index cases (N = 56). Women without a finding of preeclampsia were controls (N = 341).

RESULTS

Women with preeclampsia had 14.5% lower serum vitamin D levels than women in the control group (16.5 ng/ml vs. 19 ng/ml, p = 0.014) with 64.5% higher sFlt-1 levels (11,600 pg/ml vs. 7050 pg/ml, p < 0.001) and greater than 2 times higher endoglin levels (18.6 ng/ml vs. 8.7 ng/ml, < 0.001). After controlling for gestational age at delivery and maternal BMI, vitamin D levels were 0.88 times lower (P = 0.051), while endoglin levels were 2.5 times higher and sFlt-1 levels were 2.1 times higher than in control pregnancies (P < 0.001).

CONCLUSIONS

Women with preeclampsia at time of delivery have higher maternal antiangiogenetic factors and may have lower maternal serum vitamin D levels. These findings may lead to a better understanding of the underlying etiology of preeclampsia as well as possible modifiable treatment options which could include assuring adequate levels of maternal serum vitamin D prior to pregnancy.

Acute and Chronic Placental Abnormalities in a Multicenter Cohort of Newborn Infants with Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To examine the frequency of placental abnormalities in a multicenter cohort of newborn infants with hypoxic-ischemic encephalopathy (HIE) and to determine the association between acuity of placental abnormalities and clinical characteristics of HIE.

STUDY DESIGN

Infants born at ≥36 weeks of gestation (n = 500) with moderate or severe HIE were enrolled in the High-dose Erythropoietin for Asphyxia and Encephalopathy Trial. A placental pathologist blinded to clinical information reviewed clinical pathology reports to determine the presence of acute and chronic placental abnormalities using a standard classification system.

RESULTS

Complete placental pathologic examination was available for 321 of 500 (64%) trial participants. Placental abnormalities were identified in 273 of 321 (85%) and were more common in infants ≥40 weeks of gestation (93% vs 81%, P = .01). A combination of acute and chronic placental abnormalities (43%) was more common than either acute (20%) or chronic (21%) abnormalities alone. Acute abnormalities included meconium staining of the placenta (41%) and histologic chorioamnionitis (39%). Chronic abnormalities included maternal vascular malperfusion (25%), villitis of unknown etiology (8%), and fetal vascular malperfusion (6%). Infants with chronic placental abnormalities exhibited a greater mean base deficit at birth (-15.9 vs -14.3, P = .049) than those without such abnormalities. Patients with HIE and acute placental lesions had older mean gestational ages (39.1 vs 38.0, P < .001) and greater rates of clinically diagnosed chorioamnionitis (25% vs 2%, P < .001) than those without acute abnormalities.

CONCLUSIONS

Combined acute and chronic placental abnormalities were common in this cohort of infants with HIE, underscoring the complex causal pathways of HIE.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02811263.

Maternal serum fructosamine levels and stillbirth: a case-control study of the Stillbirth Collaborative Research Network

OBJECTIVE

To evaluate the association between maternal fructosamine levels at the time of delivery and stillbirth.

DESIGN

Secondary analysis of a case-control study.

SETTING

Multicentre study of five geographic catchment areas in the USA.

POPULATION

All singleton stillbirths with known diabetes status and fructosamine measurement, and representative live birth controls.

MAIN OUTCOME MEASURES

Fructosamine levels in stillbirths and live births among groups were adjusted for potential confounding factors, including diabetes. Optimal thresholds of fructosamine to discriminate stillbirth and live birth.

RESULTS

A total of 529 women with a stillbirth and 1499 women with a live birth were included in the analysis. Mean fructosamine levels were significantly higher in women with a stillbirth than in women with a live birth after adjustment (177 ± 3.05 versus 165 ± 2.89 μmol/L, P < 0.001). The difference in fructosamine levels between stillbirths and live births was greater among women with diabetes (194 ± 8.54 versus 162 ± 3.21 μmol/L), compared with women without diabetes (171 ± 2.50 versus 162 ± 2.56 μmol/L). The area under the curve (AUC) for fructosamine level and stillbirth was 0.634 (0.605-0.663) overall, 0.713 (0.624-0.802) with diabetes and 0.625 (0.595-0.656) with no diabetes.

CONCLUSIONS

Maternal fructosamine levels at the time of delivery were higher in women with stillbirth compared with women with live birth. Differences were substantial in women with diabetes, suggesting a potential benefit of glycaemic control in women with diabetes during pregnancy. The small differences noted in women without diabetes are not likely to justify routine screening in all cases of stillbirth.

TWEETABLE ABSTRACT

Maternal serum fructosamine levels are higher in women with stillbirth than in women with live birth, especially in women with diabetes.

Variation in self-identified most stressful life event by outcome of previous pregnancy in a population-based sample interviewed 6-36 months following delivery

The majority of health research uses a deductive approach to measure stressful life events, despite evidence that perception of what is stressful varies. The goal of this project was to 1) describe the distribution of self-identified most stressful life events in a cohort of women who experienced a perinatal loss (stillbirth or neonatal death) or live birth in the previous three years and 2) test how childhood adversity influences participant selection of their most stressful life event. We used data from 987 women (282 with stillbirth, 657 without loss, and 48 with a neonatal death in the first 28 days) in the Stillbirth Collaborative Research Network - OASIS (Outcomes after Study Index Stillbirth) follow-up study, a population-based sample set in five U.S. states in 2009. We applied an inductive coding process to open-ended responses to a question about the most stressful event or major crisis that participants had ever experienced, resulting in a set of 15 categories. We compare psychologic wellbeing across self-identified most stressful life event, accounting for sampling and loss-to-follow-up weights. Overall, stillbirth was most commonly identified as the most stressful event (18.3% [95% CI: 15.6, 21.5]), followed by loss by death of someone other than a child (17.25% [95% CI: 13.9, 20.3]). For participants who experienced a perinatal loss, we fit multivariable logistic regression models to quantify the association between report of childhood maltreatment and identifying the perinatal loss as the most stressful life event, calculating risk ratios (RRs). Reporting any moderate or severe childhood maltreatment was associated with 24% lower risk of identifying the perinatal loss as the most stressful life event (adjusted RR: 0.76 [95% CI: 0.58, 1.01]), after adjusting for race/ethnicity, age, and education. These results demonstrate the value of combining standardized measures with open-ended, inductive approaches to measuring stress in large, population-based studies.

Characteristics of Stillbirths Associated With Diabetes in a Diverse U.S. Cohort

OBJECTIVE

To characterize stillbirths associated with pregestational diabetes and gestational diabetes mellitus (GDM) in a large, prospective, U.S. case-control study.

METHODS

A secondary analysis of stillbirths among patients enrolled in a prospective; multisite; geographically, racially, and ethnically diverse case-control study in the United States was performed. Singleton gestations with complete information regarding diabetes status and with a complete postmortem evaluation were included. A standard evaluation protocol for stillbirth cases included postmortem evaluation, placental pathology, clinical testing as performed at the discretion of the health care professional, and a recommended panel of tests. A potential cause of death was assigned to stillbirth cases using a standardized classification tool. Demographic and delivery characteristics among women with pregestational diabetes and GDM were compared with characteristics of women with no diabetes in pairwise comparisons using χ or two-sample t tests as appropriate. Sensitivity analysis was performed excluding pregnancies with genetic conditions or major fetal malformations.

RESULTS

Of 455 stillbirth cases included in the primary analysis, women with stillbirth and diabetes were more likely to be older than 35 years and have a higher body mass index. They were also more likely to have a gestational hypertensive disorder than women without diabetes (28% vs 9.1%; P<.001). Women with pregestational diabetes had more large-for-gestational-age (LGA) neonates (26% vs 3.4%; P<.001). Stillbirths occurred more often at term in women with pregestational diabetes (36%) and those with GDM (52%). Maternal medical complications, including pregestational diabetes and others, were more often identified as a probable or possible cause of death among stillbirths with maternal diabetes (43% vs 4%, P<.001) as compared with stillbirths without diabetes.

CONCLUSION

Compared with stillbirths in women with no diabetes, stillbirths among women with pregestational diabetes and GDM occur later in pregnancy and are associated with hypertensive disorders of pregnancy, maternal medical complications, and LGA.

Stillbirth and fetal anomalies: secondary analysis of a case-control study

OBJECTIVE

Approximately 10% of stillbirths are attributed to fetal anomalies, but anomalies are also common in live births. We aimed to assess the relationship between anomalies, by system and stillbirth.

DESIGN

Secondary analysis of a prospective, case-control study.

SETTING

Multicentre, 59 hospitals in five regional catchment areas in the USA.

POPULATION OR SAMPLE

All stillbirths and representative live birth controls.

METHODS

Standardised postmortem examinations performed in stillbirths, medical record abstraction for stillbirths and live births.

MAIN OUTCOME MEASURES

Incidence of major anomalies, by type, compared between stillbirths and live births with univariable and multivariable analyses using weighted analysis to account for study design and differential consent.

RESULTS

Of 465 singleton stillbirths included, 23.4% had one or more major anomalies compared with 4.3% of 1871 live births. Having an anomaly increased the odds of stillbirth; an increasing number of anomalies was more highly associated with stillbirth. Regardless of organ system affected, the presence of an anomaly increased the odds of stillbirth. These relationships remained significant if stillbirths with known genetic abnormalities were excluded. After multivariable analyses, the adjusted odds ratio (aOR) of stillbirth for any anomaly was 4.33 (95% CI 2.80-6.70) and the systems most strongly associated with stillbirth were cystic hygroma (aOR 29.97, 95% CI 5.85-153.57), and thoracic (aOR16.18, 95% CI 4.30-60.94) and craniofacial (aOR 35.25, 95% CI 9.22-134.68) systems.

CONCLUSIONS

In pregnancies affected by anomalies, the odds of stillbirth are higher with increasing numbers of anomalies. Anomalies of nearly any organ system increased the odds of stillbirth even when adjusting for gestational age and maternal race.

TWEETABLE ABSTRACT

Stillbirth risk increases with anomalies of nearly any organ system and with number of anomalies seen.

Placental pathology and maternal factors associated with stillbirth: An institutional based case-control study in Northern Tanzania

OBJECTIVE

To determine the placental pathologies and maternal factors associated with stillbirth at Kilimanjaro Christian Medical Centre, a tertiary referral hospital in Northern Tanzania.

METHODS

A 1:2 unmatched case-control study was carried out among deliveries over an 8-month period. Stillbirths were a case group and live births were the control group. Respective placentas of the newborns from both groups were histopathologically analyzed. Maternal information was collected via chart review. Mean and standard deviation were used to summarize the numerical variables while frequency and percentage were used to summarize categorical variables. Crude and adjusted logistic regressions were done to test the association between each variable and the risk of stillbirth.

RESULTS

A total of 2305 women delivered during the study period. Their mean age was 30 ± 5.9 years. Of all deliveries, 2207 (95.8%) were live births while 98 (4.2%) were stillbirths. Of these, 96 stillbirths (cases) and 192 live births (controls) were enrolled. The average gestational age for the enrolled cases was 33.8 ±3.2 weeks while that of the controls was 36.3±3.6 weeks, (p-value 0.244). Of all stillbirths, nearly two thirds 61(63.5%) were males while the females were 35(36.5%). Of the stillbirth, 41were fresh stillbirths while 55 were macerated. The risk of stillbirth was significantly associated with lower maternal education [aOR (95% CI): 5.22(2.01-13.58)], history of stillbirth [aOR (95%CI): 3.17(1.20-8.36)], lower number of antenatal visits [aOR (95%CI): 6.68(2.71-16.48), pre/eclampsia [aOR (95%CI): 4.06(2.03-8.13)], and ante partum haemorrhage [OR (95%CI): 2.39(1.04-5.53)]. Placental pathology associated with stillbirth included utero-placental vascular pathology and acute chorioamnionitis.

CONCLUSIONS

Educating the mothers on the importance of regular antenatal clinic attendance, monitoring and managing maternal conditions during antenatal periods should be emphasized. Placentas from stillbirths should be histo-pathologically evaluated to better understand the possible aetiology of stillbirths.

The etiology of stillbirth over 30 years: A cross-sectional study in a tertiary referral unit

INTRODUCTION

Stillbirth remains an often unpredictable and devastating pregnancy outcome, and despite thorough investigation, the number of stillbirths attributable to unexplained causes remains high. Placental examination has become increasingly important where access to perinatal autopsy is limited. We aimed to examine the causes of stillbirth in normally formed infants over 30 years and whether a declining autopsy rate has affected our ability to determine a cause for stillbirths.

MATERIAL AND METHODS

All cases of normally formed singleton infants weighing ≥500 g that died prior to the onset of labor from 1989 to 2018 were examined. Trends for specific causes and uptake of perinatal autopsy were analyzed individually.

RESULTS

In all, 229 641 infants were delivered, with 840 stillbirths giving a rate of 3.66/1000. The rate of stillbirth declined from 4.84/1000 in 1989 to 2.51 in 2018 (P < .001). There was no difference in the rate of stillbirth between nulliparous and multiparous women (4.25 vs 3.66 per 1000, P = .026). Deaths from placental abruption fell (1.13/1000 in 1989 to 0 in 2018, P < .001) and the relative contribution of placental abruption to the incidence of stillbirth also fell, from 23.3% (7/30) in 1989 to 0.0% (0/19) in 2018 (P < .001). Stillbirth attributed to infection remained static (0.31/1000 in 1989 to 0.13 in 2018, P = .131), while a specific causal organism was found in 79.2% (42/53) of cases. Unexplained stillbirths decreased from 2.58/1000 (16/6200) in 1989 to 0.13 (1/7581) in 2018 (P < .001) despite a fall in the uptake of perinatal autopsy (96.7% [29/30] in 1989 to 36.8% (7/19) in 2018; P < .001). Placental disease emerged as a significant cause of stillbirth from 2004 onwards (89.5% [17/19] in 2018).

CONCLUSIONS

The present analysis is one of the largest single-center studies on stillbirth published to date. Stillbirth rates have fallen across the study period across parity. A decrease in deaths secondary to placental abruption contributed largely to this. Infection-related deaths are static; however, in one-fifth of cases a causative organism was not found. Despite a decreasing autopsy rate, the number of unexplained stillbirths continues to fall as the importance of placental pathology is increasingly recognized.

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.

Findings in Stillbirths Associated with Placental Disease

OBJECTIVE

Placental disease is a leading cause of stillbirth. Our purpose was to characterize stillbirths associated with placental disease.

STUDY DESIGN

The Stillbirth Collaborative Research Network conducted a prospective, case-control study of stillbirths and live births from 2006 to 2008. This analysis includes 512 stillbirths with cause of death assignment and a comparison group of live births. We compared exposures between women with stillbirth due to placental disease and those due to other causes as well as between women with term (≥ 37 weeks) stillbirth due to placental disease and term live births.

RESULTS

A total of 121 (23.6%) out of 512 stillbirths had a probable or possible cause of death due to placental disease by Initial Causes of Fetal Death. Characteristics were similar between stillbirths due to placental disease and other stillbirths. When comparing term live births to stillbirths due to placental disease, women with non-Hispanic black race, Hispanic ethnicity, lack of insurance, or who were born outside of the United States had higher odds of stillbirth due to placental disease. Nulliparity and antenatal bleeding also increased risk of stillbirth due to placental disease.

CONCLUSION

Multiple discrete exposures were associated with stillbirth caused by placental disease. The relationship between these factors and utility of surveillance warrants further study.

Stillbirth Associated With Infection in a Diverse U.S. Cohort

OBJECTIVE

To better characterize infection-related stillbirth in terms of pathogenesis and microbiology.

METHODS

We conducted a secondary analysis of 512 stillbirths in a prospective, multisite, geographically, racially and ethnically diverse, population-based study of stillbirth in the United States. Cases underwent evaluation that included maternal interview, chart abstraction, biospecimen collection, fetal autopsy, and placental pathology. Recommended evaluations included syphilis and parvovirus serology. Each case was assigned probable and possible causes of death using the INCODE Stillbirth Classification System. Cases where infection was assigned as a probable or possible cause of death were reviewed. For these cases, clinical scenario, autopsy, maternal serology, culture results, and placental pathology were evaluated.

RESULTS

For 66 (12.9%) cases of stillbirth, infection was identified as a probable or possible cause of death. Of these, 36% (95% CI 35-38%) were categorized as a probable and 64% (95% CI 62-65%) as a possible cause of death. Infection-related stillbirth occurred earlier than non-infection-related stillbirth (median gestational age 22 vs 28 weeks, P=.001). Fetal bacterial culture results were available in 47 cases (71%), of which 35 (53%) grew identifiable organisms. The predominant species were Escherichia coli (19, 29%), group B streptococcus (GBS) (8, 12%), and enterococcus species (8, 12%). Placental pathology revealed chorioamnionitis in 50 (76%), funisitis in 27 (41%), villitis in 11 (17%), deciduitis in 35 (53%), necrosis in 27 (41%), and viral staining in seven (11%) cases. Placental pathology found inflammation or evidence of infection in 65 (99%) cases and fetal autopsy in 26 (39%) cases. In infection-related stillbirth cases, the likely causative nonbacterial organisms identified were parvovirus in two (3%) cases, syphilis in one (2%) case, cytomegalovirus (CMV) in five (8%) cases, and herpes in one (2%) case.

CONCLUSION

Of infection-related stillbirth cases in a large U.S. cohort, E coli, GBS, and enterococcus species were the most common bacterial pathogens and CMV the most common viral pathogen.

The association between gestational weight gain z-score and stillbirth: a case-control study

BACKGROUND

There is limited information on potentially modifiable risk factors for stillbirth, such as gestational weight gain (GWG). Our purpose was to explore the association between GWG and stillbirth using the GWG z-score.

METHODS

We analyzed 479 stillbirths and 1601 live births from the Stillbirth Collaborative Research Network case-control study. Women with triplets or monochorionic twins were excluded from analysis. We evaluated the association between GWG z-score (modeled as a restricted cubic spline with knots at the 5th, 50th, and 95th percentiles) and stillbirth using multivariable logistic regression with generalized estimating equations, adjusting for pre - pregnancy body mass index (BMI) and other confounders. In addition, we conducted analyses stratified by pre - pregnancy BMI category (normal weight, overweight, obese).

RESULTS

Mean GWG was 18.95 (SD 17.6) lb. among mothers of stillbirths and 30.89 (SD 13.3) lb. among mothers of live births; mean GWG z-score was - 0.39 (SD 1.5) among mothers of cases and - 0.17 (SD 0.9) among control mothers. In adjusted analyses, the odds of stillbirth were elevated for women with very low GWG z-scores (e.g., adjusted odds ratio (aOR) and 95% Confidence Interval (CI) for z-score - 1.5 SD versus 0 SD: 1.52 (1.30, 1.78); aOR (95% CI) for z-score - 2.5 SD versus 0 SD: 2.36 (1.74, 3.20)). Results differed slightly by pre - pregnancy BMI. The odds of stillbirth were slightly elevated among women with overweight BMI and GWG z-scores ≥1 SD (e.g., aOR (95% CI) for z-score of 1.5 SD versus 0 SD: 1.84 (0.97, 3.50)).

CONCLUSIONS

GWG z-scores below - 1.5 SD are associated with increased odds of stillbirth.

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.

Interpregnancy interval and risk of stillbirth: a population-based case control study

PURPOSE

We examined the association between interpregnancy intervals (IPIs) and stillbirth (defined as fetal death ≥20 weeks), as both short and long IPIs have been associated with adverse perinatal outcomes. Prior pregnancy loss is also a known risk factor for stillbirth, and women who suffer a prior loss often have shorter IPIs. For these reasons, we also sought to quantify the proportion of the association between prior pregnancy loss and subsequent stillbirth risk that may be attributed to a short IPI.

METHODS

We used data from the Stillbirth Collaborative Research Network, a multisite case-control study conducted in 2006-2008, restricted to singleton pregnancies among multiparous or multigravid women (985 controls and 291 cases). We accounted for complex sample design and nonparticipation with weighted multivariable logistic regression.

RESULTS

In the adjusted models, IPIs <6 months, as compared with a reference of 18-23 months, were associated with increased odds of stillbirth (aOR 1.6, 95% CI: 0.8, 3.4). Long IPIs (60-100 months) were also associated with an increased odds of stillbirth (aOR 2.4, 95% CI: 1.2, 4.5). After control for covariates, about one-fifth (21.2%) of the association of prior pregnancy loss (stillbirth, ectopic pregnancy, molar pregnancy, or spontaneous abortion) and stillbirth may be attributable to a short IPI.

CONCLUSIONS

Our results suggest that women who experience a prior pregnancy loss may benefit from additional counseling on adequate birth spacing to reduce subsequent stillbirth risk.

Associations Between the Features of Gross Placental Morphology and Birthweight

The placenta plays a critical role in regulating fetal growth. Recent studies suggest that there may be sex-specific differences in placental development. The purpose of our study was to evaluate the associations between birthweight and placental morphology in models adjusted for covariates and to assess sex-specific differences in these associations. We analyzed data from the Stillbirth Collaborative Research Network's population-based case-control study conducted between 2006 and 2008, which recruited cases of stillbirth and population-based controls in 5 states. Our analysis was restricted to singleton live births with a placental examination (n = 1229). Characteristics of placental morphology evaluated include thickness, surface area, difference in diameters, shape, and umbilical cord insertion site. We used linear regression to model birthweight as a function of placental morphology and covariates. Surface area had the greatest association with birthweight; a reduction in surface area of 83 cm2, which reflects the interquartile range, is associated with a 260.2-g reduction in birthweight (95% confidence interval, -299.9 to -220.6), after adjustment for other features of placental morphology and covariates. Reduced placental thickness was also associated with lower birthweight. These associations did not differ between males and females. Our results suggest that reduced placental thickness and surface area are independently associated with lower birthweight and that these relationships are not related to sex.

Associations Between Features of Placental Morphology and Birth Weight in Dichorionic Twins

Low birth weight is associated with perinatal and long-term morbidity and mortality, and may be a result of abnormal placental development and function. In studies of singletons, associations have been reported between features of placental morphology and birth weight. Evaluating similar associations within twin pairs offers a unique opportunity to control for key confounders shared within a twin pair, including gestational age, parental characteristics, and intrauterine environment. Data from 3 studies in the United States that were completed from 2012 to 2013, 2006 to 2008, and 1959 to 1966 were used in our analysis of 208 sets of dichorionic twins with unfused placentas. We used linear regression to model difference in birth weight within a twin pair as a function of differences in placental characteristics (i.e., thickness, 2-dimensional surface area, intraplacental difference in diameter). After controlling for sex discordance, a 75.3- cm2 difference in placental surface area, which reflects the interquartile range, was associated with a difference in birth weight of 142.1 g (95% confidence interval (CI): 62.9, 221.3). The magnitude of the association also may be larger for same-sex male pairs than same-sex female pairs (males: 265.8 g, 95% CI: 60.8, 470.8; females: 133.0 g, 95% CI: 15.7, 250.3). Strong associations between surface area and birth weight are consistent with reported results for singleton pregnancies.

Complement Activation During Early Pregnancy and Clinical Predictors of Preterm Birth in African American Women

Complement activation is essential for select physiologic processes during pregnancy; however, excess activation has been associated with an increased risk for preterm birth (PTB). African American (AA) women experience disproportionately higher rates of inflammation-associated PTB than other groups of women; thus, the purpose of this study was to explore the relationship between complement activation and perinatal outcomes among AA women. A plasma sample was collected between 8 and 14 weeks' gestation from a cohort of healthy AA women (N = 144) enrolled in a larger PTB cohort study. Medical record review was conducted to collect information on clinical factors (cervical length, health behaviors, gestational age at delivery). Multiple regression analysis was used to explore the relationships between complement marker (C3a/Bb) concentrations and the outcomes of interest after adjusting for baseline characteristics. C3a/Bb concentrations were not significant predictors of the gestational age at delivery, cervical length, or behavioral risk factors for PTB in this sample. Complement markers may not influence pregnancy outcomes among AA women in the same way as in predominantly white populations; however, more studies are needed to define complement dysregulation and the relationship with outcomes among AA women.

Stillbirth, Inflammatory Markers, and Obesity: Results from the Stillbirth Collaborative Research Network

BACKGROUND

Obesity is associated with increased risk of stillbirth, although the mechanisms are unknown. Obesity is also associated with inflammation. Serum ferritin, C-reactive protein, white blood cell count, and histologic chorioamnionitis are all markers of inflammation.

OBJECTIVE

This article determines if inflammatory markers are associated with stillbirth and body mass index (BMI). Additionally, we determined whether inflammatory markers help to explain the known relationship between obesity and stillbirth.

STUDY DESIGN

White blood cell count was assessed at admission to labor and delivery, maternal serum for assessment of various biomarkers was collected after study enrollment, and histologic chorioamnionitis was based on placental histology. These markers were compared for stillbirths and live births overall and within categories of BMI using analysis of variance on logarithmic-transformed markers and logistic regression for dichotomous variables. The impact of inflammatory markers on the association of BMI categories with stillbirth status was assessed using crude and adjusted odds ratios (COR and AOR, respectively) from logistic regression models. The interaction of inflammatory markers and BMI categories on stillbirth status was also assessed through logistic regression. Additional logistic regression models were used to determine if the association of maternal serum ferritin with stillbirth is different for preterm versus term births. Analyses were weighted for the overall population from which this sample was derived.

RESULTS

A total of 497 women with singleton stillbirths and 1,414 women with live births were studied with prepregnancy BMI (kg/m²) categorized as normal (18.5-24.9), overweight (25.0-29.9), or obese (30.0 + ). Overweight (COR, 1.48; 95% confidence interval [CI]: 1.14-1.94) and obese women (COR, 1.60; 95% CI: 1.23-2.08) were more likely than normal weight women to experience stillbirth. Serum ferritin levels were higher (geometric mean: 37.4 ng/mL vs. 23.3, p < 0.0001) and C-reactive protein levels lower (geometric mean: 2.9 mg/dL vs. 3.3, p = 0.0279), among women with stillbirth compared with live birth. Elevated white blood cell count (15.0 uL × 10³ or greater) was associated with stillbirth (21.2% SB vs. 10.0% live birth, p < 0.0001). Histologic chorioamnionitis was more common (33.2% vs. 15.7%, p < 0.0001) among women with stillbirth compared with those with live birth. Serum ferritin, C-reactive protein, and chorioamnionitis had little impact on the ORs associating stillbirth with overweight or obesity. Adjustment for elevated white blood cell count did not meaningfully change the OR for stillbirth in overweight versus normal weight women. However, the stillbirth OR for obese versus normal BMI changed by more than 10% when adjusting for histologic chorioamnionitis (AOR, 1.38; 95% CI: 1.02-1.88), indicating confounding. BMI by inflammatory marker interaction terms were not significant. The association of serum ferritin levels with stillbirth was stronger among preterm births (p = 0.0066).

CONCLUSION

Maternal serum ferritin levels, elevated white blood cell count, and histologic chorioamnionitis were positively and C-reactive protein levels negatively associated with stillbirth. Elevated BMIs, both overweight and obese, were associated with stillbirth when compared with women with normal BMI. None of the inflammatory markers fully accounted for the relationship between obesity and stillbirth. The association of maternal serum ferritin with stillbirth was stronger in preterm than term stillbirths.

Comparison of diameter-based and image-based measures of surface area from gross placental pathology for use in epidemiologic studies

Placental surface area is often estimated using diameter measurements. However, as many placentas are not elliptical, we were interested in the validity of these estimates. We compared placental surface area from images for 491 singletons from the Stillbirth Collaborative Research Network (SCRN) Study (416 live births, 75 stillbirths) to estimates obtained using diameter measurements. Placental images and diameters were obtained from pathologic assessments conducted for the SCRN Study and images were analyzed using ImageJ software. On average, diameter-based measures underestimated surface area by -5.58% (95% confidence interval: -30.23, 19.07); results were consistent for normal and abnormal shapes. The association between surface area and birthweight was similar for both measures. Thus, diameter-based surface area can be used to estimate placental surface area.

Smith-Lemli-Opitz Mutations in Unexplained Stillbirths

OBJECTIVE

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive syndrome caused by a defect in cholesterol biosynthesis with mutations in 7-dehydrocholesterol reductase (DHCR7). A total of 3% of Caucasians carry DHCR7 mutations, theoretically resulting in a homozygote frequency of 1/4000. However, SLOS occurs in only 1/20,000 to 60,000 live births. Our objective was to assess DHCR7 mutations in unexplained stillbirths.

STUDY DESIGN

Prospective, multicenter, population-based case-control study of all stillbirths and a representative sample of live births enrolled in five geographic areas. Cases with stillbirth due to obstetric complications, infection, or aneuploidy, and those with poor quality deoxyribonucleic acid (DNA) were excluded. DNA was extracted from placental tissue stored at -80°C, and exons 3 to 9 of the DCHR7 gene were amplified, purified, and subjected to bidirectional sequencing to identify mutations.

RESULTS

One-hundred forty four stillbirths were unexplained and had adequate DNA for analysis. Nine stillbirths of 139 (6.5%) had a single mutation in one allele in coding exons 3 to 9 of DHCR7 (Table 1). One case (0.7%) was a compound heterozygote for mutations in exons 3 to 9 of DHCR7; this fetus had no clinical or histologic features of SLOS.

CONCLUSION

We detected SLOS mutations in only 0.7% of stillbirths. This does not support a strong association between unrecognized DHCR7 mutations and stillbirth.

Association of participation in a supplemental nutrition program with stillbirth by race, ethnicity, and maternal characteristics

BACKGROUND

Participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) has been associated with lower risk of stillbirth. We hypothesized that such an association would differ by race/ethnicity because of factors associated with WIC participation that confound the association.

METHODS

We conducted a secondary analysis of the Stillbirth Collaborative Research Network's population-based case-control study of stillbirths and live-born controls, enrolled at delivery between March 2006 and September 2008. Weighting accounted for study design and differential consent. Five nested models using multivariable logistic regression examined whether the WIC participation/stillbirth associations were attenuated after sequential adjustment for sociodemographic, health, healthcare, socioeconomic, and behavioral factors. Models also included an interaction term for race/ethnicity x WIC.

RESULTS

In the final model, WIC participation was associated with lower adjusted odds (aOR) of stillbirth among non-Hispanic Black women (aOR: 0.34; 95% CI 0.16, 0.72) but not among non-Hispanic White (aOR: 1.69; 95% CI: 0.89, 3.20) or Hispanic women (aOR: 0.91; 95% CI 0.52, 1.52).

CONCLUSIONS

Contrary to our hypotheses, control for potential confounding factors did not explain disparate findings by race/ethnicity. Rather, WIC may be most beneficial to women with the greatest risk factors for stillbirth. WIC-eligible, higher-risk women who do not participate may be missing the potential health associated benefits afforded by WIC.

Examining the link between placental pathology, growth restriction, and stillbirth

Stillbirth, often defined as death of a fetus ≥20 weeks of gestation, is emotionally devastating for families and caregivers. It is often associated with fetal growth restriction (FGR). Indeed, FGR or small-for-gestational age fetus (SGA) is a major risk factor for stillbirth. In rare cases, this is due to genetic abnormalities or infections. However, in most cases, it is linked to placental insufficiency. This may be due to abnormal placental development or placental damage, thereby resulting in decreased blood flow, oxygen, and nutrients to the fetus. Several placental histological abnormalities are associated with stillbirth, FGR, or both. Most involve vascular abnormalities but some are inflammatory lesions. This paper reviews evidence regarding the relationships between placental function and pathology, FGR, and stillbirth. Issues with clinical relevance, knowledge gaps, and areas for further research are highlighted.

Potentially Preventable Stillbirth in a Diverse U.S. Cohort

OBJECTIVE

To estimate the proportion of potentially preventable stillbirths in the United States.

METHODS

We conducted a secondary analysis of 512 stillbirths with complete evaluation enrolled in the Stillbirth Collaborative Research Network from 2006 to 2008. The Stillbirth Collaborative Research Network was a multisite, geographically, racially, and ethnically diverse, population-based case-control study of stillbirth in the United States. Cases of stillbirth underwent standard evaluation that included maternal interview, medical record abstraction, biospecimen collection, postmortem examination, placental pathology, and clinically recommended evaluation. Each stillbirth was assigned probable and possible causes of death using the Initial Causes of Fetal Death algorithm system. For this analysis, we defined potentially preventable stillbirths as those occurring in nonanomalous fetuses, 24 weeks of gestation or greater, and weighing 500 g or greater that were 1) intrapartum, 2) the result of medical complications, 3) the result of placental insufficiency, 4) multiple gestation (excluding twin-twin transfusion), 5) the result of spontaneous preterm birth, or 6) the result of hypertensive disorders of pregnancy.

RESULTS

Of the 512 stillbirths included in our cohort, causes of potentially preventable stillbirth included placental insufficiency (65 [12.7%]), medical complications of pregnancy (31 [6.1%]), hypertensive disorders of pregnancy (20 [3.9%]), preterm labor (16 [3.1%]), intrapartum (nine [1.8%]), and multiple gestations (four [0.8%]). Twenty-seven stillbirths fit two or more categories, leaving 114 (22.3%) potentially preventable stillbirths.

CONCLUSION

Based on our definition, almost one fourth of stillbirths are potentially preventable. Given the predominance of placental insufficiency among stillbirths, identification and management of placental insufficiency may have the most immediate effect on stillbirth reduction.

Maternal marijuana use, adverse pregnancy outcomes, and neonatal morbidity

BACKGROUND

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Stillbirth Collaborative Research Network previously demonstrated an association between stillbirth and maternal marijuana use as defined by the presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in the umbilical cord homogenate. However, the relationship between marijuana use and perinatal complications in live births is uncertain.

OBJECTIVE

Our aim was to examine if maternal marijuana use is associated with increased odds of adverse pregnancy outcomes and neonatal morbidity among live-born controls in the Stillbirth Collaborative Research Network cohort.

STUDY DESIGN

We conducted a secondary analysis of singleton, live-born controls in the Stillbirth Collaborative Research Network data set. Marijuana use was measured by self-report and/or the presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in umbilical cord homogenate. Tobacco use was measured by self-report and/or presence of any cotinine in maternal serum. Adverse pregnancy outcome was a composite of small for gestational age, spontaneous preterm birth resulting from preterm labor with or without intact membranes, and hypertensive disorders of pregnancy. Neonatal morbidity included neonatal intensive care unit admission and composite neonatal morbidity (pulmonary morbidity, necrotizing enterocolitis, seizures, retinopathy of prematurity, infection morbidity, anemia requiring blood transfusion, neonatal surgery, hyperbilirubinemia, neurological morbidity, or death prior to hospital discharge). Effect of maternal marijuana use on the probability of an adverse outcome was estimated using weighted methodology to account for oversampling in the original study. 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid cord homogenate analysis was performed in the subset of women for whom biospecimens were available. Comparisons using logistic modeling, χ², and t tests were weighted to account for oversampling of preterm births and non-Hispanic blacks. Results are reported as weighted percent and unweighted frequencies.

RESULTS

Maternal marijuana use was identified in 2.7% (unweighted frequency 48/1610) of live births. Use was self-reported by 1.6% (34/1610) and detected by 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in cord homogenate for 1.9% (17/897), n = 3 overlapping. Rate of tobacco use was 12.9% (217/1610), with 10.7% (167/1607) by self-report and 9.5% (141/1313) by serum cotinine. The composite adverse pregnancy outcome was not significantly increased in women with marijuana use compared to nonusers (31.2% vs 21.2%; P = .14). After adjustment for tobacco, clinical, and socioeconomic factors, marijuana use was not associated with the composite adverse pregnancy outcome (adjusted odds ratio, 1.29; 95% confidence interval, 0.56-2.96). Similarly, among women with umbilical cord homogenate and serum cotinine data (n = 765), marijuana use was not associated with adverse pregnancy outcomes (adjusted odds ratio, 1.02; 95% confidence interval, 0.18-5.66). Neonatal intensive care unit admission rates were not statistically different between groups (16.9% users vs 9.5% nonusers, P = .12). Composite neonatal morbidity or death was more frequent among neonates of mothers with marijuana use compared to nonusers (14.1% vs 4.5%; P = .002). In univariate comparisons, the components of the composite outcome that were more frequent in neonates of marijuana users were infection morbidity (9.8% vs 2.4%; P < .001) and neurologic morbidity (1.4% vs 0.3%; P = .002). After adjustment for tobacco, race, and other illicit drug use, marijuana use was still associated with composite neonatal morbidity or death (adjusted odds ratio, 3.11; 95% confidence interval, 1.40-6.91).

CONCLUSION

Maternal marijuana use was not associated with a composite of small for gestational age, spontaneous preterm birth, or hypertensive disorders of pregnancy. However, it was associated with an increased risk of neonatal morbidity.

Altered fetal growth, placental abnormalities, and stillbirth

Background

Worldwide, stillbirth is one of the leading causes of death. Altered fetal growth and placental abnormalities are the strongest and most prevalent known risk factors for stillbirth. The aim of this study was to identify patterns of association between placental abnormalities, fetal growth, and stillbirth.

Methods and findings

Population-based case-control study of all stillbirths and a representative sample of live births in 59 hospitals in 5 geographic areas in the U.S. Fetal growth abnormalities were categorized as small (<10th percentile) and large (>90th percentile) for gestational age at death (stillbirth) or delivery (live birth) using a published algorithm. Placental examination by perinatal pathologists was performed using a standardized protocol. Data were weighted to account for the sampling design. Among 319 singleton stillbirths and 1119 singleton live births at ≥24 weeks at death or delivery respectively, 25 placental findings were investigated. Fifteen findings were significantly associated with stillbirth. Ten of the 15 were also associated with fetal growth abnormalities (single umbilical artery; velamentous insertion; terminal villous immaturity; retroplacental hematoma; parenchymal infarction; intraparenchymal thrombus; avascular villi; placental edema; placental weight; ratio birth weight/placental weight) while 5 of the 15 associated with stillbirth were not associated with fetal growth abnormalities (acute chorioamnionitis of placental membranes; acute chorioamionitis of chorionic plate; chorionic plate vascular degenerative changes; perivillous, intervillous fibrin, fibrinoid deposition; fetal vascular thrombi in the chorionic plate). Five patterns were observed: placental findings associated with (1) stillbirth but not fetal growth abnormalities; (2) fetal growth abnormalities in stillbirths only; (3) fetal growth abnormalities in live births only; (4) fetal growth abnormalities in stillbirths and live births in a similar manner; (5) a different pattern of fetal growth abnormalities in stillbirths and live births.

Conclusions

The patterns of association between placental abnormalities, fetal growth, and stillbirth provide insights into the mechanism of impaired placental function and stillbirth. They also suggest implications for clinical care, especially for placental findings amenable to prenatal diagnosis using ultrasound that may be associated with term stillbirths.

Fetal death certificate data quality: a tale of two U.S. counties

PURPOSE

Describe the relative frequency and joint effect of missing and misreported fetal death certificate (FDC) data and identify variations by key characteristics.

METHODS

Stillbirths were prospectively identified during 2006-2008 for a multisite population-based case-control study. For this study, eligible mothers of stillbirths were not incarcerated residents of DeKalb County, Georgia, or Salt Lake County, Utah, aged ≥13 years, with an identifiable FDC. We identified the frequency of missing and misreported (any departure from the study value) FDC data by county, race/ethnicity, gestational age, and whether the stillbirth was antepartum or intrapartum.

RESULTS

Data quality varied by item and was highest in Salt Lake County. Reporting was generally not associated with maternal or delivery characteristics. Reasons for poor data quality varied by item in DeKalb County: some items were frequently missing and misreported; however, others were of poor quality due to either missing or misreported data.

CONCLUSIONS

FDC data suffer from missing and inaccurate data, with variations by item and county. Salt Lake County data illustrate that high quality reporting is attainable. The overall quality of reporting must be improved to support consequential epidemiologic analyses for stillbirth, and improvement efforts should be tailored to the needs of each jurisdiction.

Maternal exposure to childhood maltreatment and risk of stillbirth

PURPOSE

To determine the association between maternal exposure to childhood maltreatment (CM) and risk of stillbirth (fetal death at or after 20 weeks' gestation).

METHODS

Population-based case-control study from the Stillbirth Collaborative Research Network (SCRN) conducted in 2006-2008, and the follow-up study, SCRN-Outcomes after Study Index Stillbirth (SCRN-OASIS), conducted in 2009 in the United States. Cases (n = 133) included women who experienced a stillbirth, excluding stillbirths attributed to genetic/structural or umbilical cord abnormalities and intrapartum stillbirths. Controls (n = 500) included women delivering a healthy term live birth (excluding births less than 37 weeks gestation, neonatal intensive care unit admission, or death). CM exposure was measured using the Childhood Trauma Questionnaire, administered during the SCRN-OASIS study. Dichotomized scores for five subscales of CM (physical abuse, physical neglect, emotional abuse, emotional neglect, and sexual abuse) and an overall measure of CM exposure were analyzed using logistic regression.

RESULTS

Generally, there was no association between CM and stillbirth, except for the emotional neglect subscale (OR: 1.93; 95% CI: 1.17, 3.19).

CONCLUSIONS

Childhood neglect is understudied in comparison to abuse and should be included in the future studies of associations between CM and pregnancy outcomes, including stillbirth.

Associations between Maternal and Fetal Inherited Thrombophilias, Placental Characteristics Associated with Vascular Malperfusion, and Fetal Growth

Pregnancy results in alterations in coagulation processes, which may increase the risk of thrombosis. Inherited thrombophilia mutations may further increase this risk, possibly through alterations in the placenta, which may result in pregnancy complications such as poor fetal growth. The purpose of our study is to evaluate the association of fetal growth, approximated by birth weight for gestational age percentile, with genetic markers of thrombophilia and placental characteristics related to vascular malperfusion. We analyzed data from the Stillbirth Collaborative Research Network's population-based case–control study conducted in 2006–2008. Study recruitment occurred in five states: Rhode Island and counties in Massachusetts, Georgia, Texas, and Utah. The analysis was restricted to singleton, nonanomalous live births ≤42 weeks' gestation with a complete placental examination and successful testing for ≥1 thrombophilia marker (858 mothers, 902 infants). Data were weighted to account for oversampling, differential consent, and availability of placental examination. We evaluated five thrombophilia markers: factor V Leiden, factor II prothrombin, methylenetetrahydrofolate reductase A1298C and C677T, and plasminogen activator inhibitor type 1 in both maternal blood and placenta/cord blood. We modeled maternal and fetal thrombophilia markers separately using linear regression. Maternal factor V Leiden mutation was associated with a 13.16-point decrease in adjusted birth weight percentile (95% confidence interval: −25.50, −0.82). Adjustment for placental abnormalities related to vascular malperfusion did not affect the observed association. No other maternal or fetal thrombophilia markers were significantly associated with birth weight percentile. Maternal factor V Leiden may be associated with fetal growth independent of placental characteristics.

Route of Delivery in Women With Stillbirth: Results From the Stillbirth Collaborative Research Network

OBJECTIVE

To describe delivery management of singleton stillbirths in a population-based, multicenter case series.

METHODS

We conducted a retrospective chart review of 611 women with singleton stillbirths at 20 weeks of gestation or greater from March 2006 to September 2008. Medical and delivery information was abstracted from medical records. Both antepartum and intrapartum stillbirths were included; these were analyzed both together and separately. The primary outcome was mode of delivery. Secondary outcomes included induction of labor and indications for cesarean delivery. Indications for cesarean delivery were classified as obstetric (abnormal fetal heart tracing before intrapartum demise, abruption, coagulopathy, uterine rupture, placenta previa, or labor dystocia) or nonobstetric (patient request, repeat cesarean delivery, or not documented).

RESULTS

Of the 611 total cases of stillbirth, 93 (15.2%) underwent cesarean delivery, including 43.0% (46/107) of women with prior cesarean delivery and 9.3% (47/504) of women without prior cesarean delivery. No documented obstetric indication was evident for 38.3% (18/47) of primary and 78.3% (36/46) of repeat cesarean deliveries. Labor induction resulted in vaginal delivery for 98.5% (321/326) of women without prior cesarean delivery and 91.1% (41/45) of women with a history of prior cesarean delivery, including two women who had uterine rupture. Among women with a history of prior cesarean delivery who had spontaneous labor, 74.1% (20/27) delivered vaginally, with no cases of uterine rupture.

CONCLUSION

Women with stillbirth usually delivered vaginally regardless of whether labor was spontaneous or induced or whether they had a prior cesarean delivery. However, 15% underwent cesarean delivery, often without a documented obstetric indication.

Factor V Leiden, prothrombin G20210A, and methylene tetrahydrofolate reductase mutations and stillbirth: the Stillbirth Collaborative Research Network

BACKGROUND

An evaluation for heritable thrombophilias is recommended in the evaluation of stillbirth. However, the association between thrombophilias and stillbirth remains uncertain.

OBJECTIVE

We sought to assess the association between maternal and fetal/placental heritable thrombophilias and stillbirth in a population-based, case-control study in a geographically, racially, and ethnically diverse population.

STUDY DESIGN

We conducted secondary analysis of data from the Stillbirth Collaborative Research Network, a population-based case-control study of stillbirth. Testing for factor V Leiden, prothrombin G20210A, methylene tetrahydrofolate reductase C677T and A1298C, and plasminogen activating inhibitor (PAI)-1 4G/5G mutations was done on maternal and fetal (or placental) DNA from singleton pregnancies. Data analyses were weighted for oversampling and other aspects of the design. Odds ratios (OR) were generated from univariate models regressing stillbirth/live birth status on each thrombophilia marker.

RESULTS

Results were available for ≥1 marker in 488 stillbirths and 1342 live birth mothers and 405 stillbirths and 990 live birth fetuses. There was an increased odds of stillbirth for maternal homozygous factor V Leiden mutation (2/488; 0.4% vs 1/1380; 0.0046%; OR, 87.44; 95% confidence interval, 7.88-970.92). However, there were no significant differences in the odds of stillbirth for any other maternal thrombophilia, even after stratified analyses. Fetal 4G/4G PAI-1 (OR, 0.63; 95% confidence interval, 0.43-0.91) was associated with decreased odds of stillbirth. Other fetal thrombophilias were similar among groups.

CONCLUSION

Most maternal and fetal thrombophilias were not associated with stillbirth. Maternal factor V Leiden was weakly associated with stillbirth, and the fetal PAI-1 4G/4G polymorphism was associated with live birth. Our data do not support routine testing for heritable thrombophilias as part of an evaluation for possible causes of stillbirth.

Stillbirth, hypertensive disorders of pregnancy, and placental pathology

INTRODUCTION

Stillbirth, preeclampsia, and gestational hypertension (PE/GH) have similar clinical risk factors and redundant placental pathology. We aim to discern if stillbirth with PE/GH has a particular phenotype by comparing stillbirths with and without PE/GH.

METHODS

Secondary analysis of the Stillbirth Collaborative Research Network, a population-based cohort study of all stillbirths and a sample of live births from 2006 to 2008 in five catchment areas. We compared placental pathology between stillbirths and with and without PE/GH, stratified by term or preterm. We also compared placental pathology between stillbirths and live births with PE/GH.

RESULTS

79/518 stillbirths and 140/1200 live births had PE/GH. Amongst preterm stillbirths, there was higher feto-placental ratio in PE/GH pregnancies (OR 1.24 [1.11, 1.37] per unit increase), and there were more parenchymal infarctions (OR 5.77 [3.18, 10.47]). Among PE/GH pregnancies, stillbirths had increased maternal and fetal vascular lesions, including retroplacental hematoma, parenchymal infarction, fibrin deposition, fetal vascular thrombi, and avascular villi.

DISCUSSION

Stillbirth pregnancies are overwhelmingly associated with placental lesions. Parenchymal infarctions are more common in PE/GH preterm stillbirths, but there is significant overlap in lesions found in stillbirths and PE/GH.