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

Intrauterine Fetal Death in Term Pregnancy-A Single Tertiary Clinic Study

INTRODUCTION

Intrauterine fetal death (IUFD) is defined as death of the fetus after the 20th week of gestation. Despite regular monitoring the incidence of IUFD remains high. This study aims to assess the incidence and maternal conditions associated with IUFD over term pregnancies in a twelve-year period.

MATERIALS AND METHODS

A retrospective descriptive study was conducted on a population of women in whom IUFD was diagnosed in a term pregnancy during the period from January 2010 to December 2022. The study was at the Clinic for Obstetrics and Gynecology, University Clinic Centre of Serbia. The analyses included the number of deliveries, live births, and stillbirths, as well as maternal, fetal, and placental conditions associated with the risk of IUDF. The statistical analysis involved descriptive statistical methods and one sample proportion.

RESULTS

The average age of the patients was 30 years. Most patients had secondary and higher education, and 70% of patients had regular pregnancy monitoring; 53.33% were primiparous and pregnancies occurred spontaneously. IUFD mainly occurred in the 39th week of gestation. In total, 38.3% had one to two associated diseases, 5% more than three, and 58.33% were healthy. Recurrence of IUFD was reported by 10% of patients, while 8.33% had a history of spontaneous abortion. Over 80% of placental histopathological findings indicated some pathology (e.g., infarction, infections, placental abruption).

CONCLUSIONS

The most significant risk factors for IUFD in term pregnancies in our population during the study period were hypertensive syndrome in pregnancy, obesity and gestational diabetes. Pathological findings on the placenta were more common in our study group than is usually reported with infractions of placental tissue being the most common, even in healthy women.

Proteomic profile of extracellular vesicles in maternal plasma of women with fetal death

OBJECTIVES

Fetal death is a complication of pregnancy caused by multiple etiologies rather than being the end-result of a single disease process. Many soluble analytes in the maternal circulation, such as hormones and cytokines, have been implicated in its pathophysiology. However, changes in the protein content of extracellular vesicles (EVs), which could provide additional insight into the disease pathways of this obstetrical syndrome, have not been examined. This study aimed to characterize the proteomic profile of EVs in the plasma of pregnant women who experienced fetal death and to evaluate whether such a profile reflected the pathophysiological mechanisms of this obstetrical complication. Moreover, the proteomic results were compared to and integrated with those obtained from the soluble fraction of maternal plasma.

METHODS

This retrospective case-control study included 47 women who experienced fetal death and 94 matched, healthy, pregnant controls. Proteomic analysis of 82 proteins in the EVs and the soluble fractions of maternal plasma samples was conducted by using a bead-based, multiplexed immunoassay platform. Quantile regression analysis and random forest models were implemented to assess differences in the concentration of proteins in the EV and soluble fractions and to evaluate their combined discriminatory power between clinical groups. Hierarchical cluster analysis was applied to identify subgroups of fetal death cases with similar proteomic profiles. A p-value of <.05 was used to infer significance, unless multiple testing was involved, with the false discovery rate controlled at the 10% level (q < 0.1). All statistical analyses were performed by using the R statistical language and environment-and specialized packages.

RESULTS

Nineteen proteins (placental growth factor, macrophage migration inhibitory factor, endoglin, regulated upon activation normal T cell expressed and presumably secreted (RANTES), interleukin (IL)-6, macrophage inflammatory protein 1-alpha, urokinase plasminogen activator surface receptor, tissue factor pathway inhibitor, IL-8, E-Selectin, vascular endothelial growth factor receptor 2, pentraxin 3, IL-16, galectin-1, monocyte chemotactic protein 1, disintegrin and metalloproteinase domain-containing protein 12, insulin-like growth factor-binding protein 1, matrix metalloproteinase-1(MMP1), and CD163) were found to have different plasma concentrations (of an EV or a soluble fraction) in women with fetal death compared to controls. There was a similar pattern of change for the dysregulated proteins in the EV and soluble fractions and a positive correlation between the log₂-fold changes of proteins significant in either the EV or the soluble fraction (ρ = 0.89, p < .001). The combination of EV and soluble fraction proteins resulted in a good discriminatory model (area under the ROC curve, 82%; sensitivity, 57.5% at a 10% false-positive rate). Unsupervised clustering based on the proteins differentially expressed in either the EV or the soluble fraction of patients with fetal death relative to controls revealed three major clusters of patients.

CONCLUSION

Pregnant women with fetal death have different concentrations of 19 proteins in the EV and soluble fractions compared to controls, and the direction of changes in concentration was similar between fractions. The combination of EV and soluble protein concentrations revealed three different clusters of fetal death cases with distinct clinical and placental histopathological characteristics.

Stillbirths: Contribution of preterm birth and size-for-gestational age for 125.4 million total births from nationwide records in 13 countries, 2000-2020

OBJECTIVE

To examine the contribution of preterm birth and size-for-gestational age in stillbirths using six 'newborn types'.

DESIGN

Population-based multi-country analyses.

SETTING

Births collected through routine data systems in 13 countries.

SAMPLE

125 419 255 total births from 22+0 to 44+6 weeks' gestation identified from 2000 to 2020.

METHODS

We included 635 107 stillbirths from 22+0  weeks' gestation from 13 countries. We classified all births, including stillbirths, into six 'newborn types' based on gestational age information (preterm, PT, <37+0  weeks versus term, T, ≥37+0  weeks) and size-for-gestational age defined as small (SGA, <10th centile), appropriate (AGA, 10th-90th centiles) or large (LGA, >90th centile) for gestational age, according to the international newborn size for gestational age and sex INTERGROWTH-21st standards.

MAIN OUTCOME MEASURES

Distribution of stillbirths, stillbirth rates and rate ratios according to six newborn types.

RESULTS

635 107 (0.5%) of the 125 419 255 total births resulted in stillbirth after 22+0  weeks. Most stillbirths (74.3%) were preterm. Around 21.2% were SGA types (PT + SGA [16.2%], PT + AGA [48.3%], T + SGA [5.0%]) and 14.1% were LGA types (PT + LGA [9.9%], T + LGA [4.2%]). The median rate ratio (RR) for stillbirth was highest in PT + SGA babies (RR 81.1, interquartile range [IQR], 68.8-118.8) followed by PT + AGA (RR 25.0, IQR, 20.0-34.3), PT + LGA (RR 25.9, IQR, 13.8-28.7) and T + SGA (RR 5.6, IQR, 5.1-6.0) compared with T + AGA. Stillbirth rate ratios were similar for T + LGA versus T + AGA (RR 0.7, IQR, 0.7-1.1). At the population level, 25% of stillbirths were attributable to small-for-gestational-age.

CONCLUSIONS

In these high-quality data from high/middle income countries, almost three-quarters of stillbirths were born preterm and a fifth small-for-gestational age, with the highest stillbirth rates associated with the coexistence of preterm and SGA. Further analyses are needed to better understand patterns of gestation-specific risk in these populations, as well as patterns in lower-income contexts, especially those with higher rates of intrapartum stillbirth and SGA.

COVID-19 Vaccine Hesitancy among English-Speaking Pregnant Women Living in Rural Western United States

This mixed-method study investigated vaccine hesitancy among pregnant women living in rural western United States and their response to social media ads promoting COVID-19 vaccine uptake. Thirty pregnant or recently pregnant participants who live in rural zip codes in Washington, Oregon, California, and Idaho were interviewed between November 2022 and March 2023. Interviews were transcribed and coded, while the ad ratings were analyzed using linear mixed models. The study identified five main themes related to vaccine uptake, including perceived risk of COVID, sources of health information, vaccine hesitancy, and relationships with care providers. Participants rated ads most highly that used peer-based messengers and negative outcome-based content. Ads with faith-based and elder messengers were rated significantly lower than peer messengers (p = 0.04 and 0.001, respectively). An activation message was also rated significantly less favorably than negative outcome-based content (p = 0.001). Participants preferred evidence-based information and the ability to conduct their own research on vaccine safety and efficacy rather than being told to get vaccinated. Primary concerns of vaccine-hesitant respondents included the short amount of time the vaccine had been available and perceived lack of research on its safety during pregnancy. Our findings suggests that tailored messaging using peer-based messengers and negative outcome-based content can positively impact vaccine uptake among pregnant women living in rural areas of the Western United States.

Risk factors of stillbirths in four district hospitals on Pemba Island, Tanzania: a prospective cohort study

BACKGROUND

More than 2 million third-trimester stillbirths occur yearly, most of them in low- and middle-income countries. Data on stillbirths in these countries are rarely collected systematically. This study investigated the stillbirth rate and risk factors associated with stillbirth in four district hospitals in Pemba Island, Tanzania.

METHODS

A prospective cohort study was completed between the 13th of September and the 29th of November 2019. All singleton births were eligible for inclusion. Events and history during pregnancy and indicators for adherence to guidelines were analysed in a logistic regression model that identified odds ratios [OR] with a 95% confidence interval [95% CI].

RESULTS

A stillbirth rate of 22 per 1000 total births in the cohort was identified; 35.5% were intrapartum stillbirths (total number of stillbirths in the cohort, n = 31). Risk factors for stillbirth were breech or cephalic malpresentation (OR 17.67, CI 7.5-41.64), decreased or no foetal movements (OR 2.6, CI 1.13-5.98), caesarean section [CS] (OR 5.19, CI 2.32-11.62), previous CS (OR 2.63, CI 1.05-6.59), preeclampsia (OR 21.54, CI 5.28-87.8), premature rupture of membranes or rupture of membranes 18 h before birth (OR 2.5, CI 1.06-5.94) and meconium stained amniotic fluid (OR 12.03, CI 5.23-27.67). Blood pressure was not routinely measured, and 25% of women with stillbirths with no registered foetal heart rate [FHR] at admission underwent CS.

CONCLUSIONS

The stillbirth rate in this cohort was 22 per 1000 total births and did not fulfil the Every Newborn Action Plan's goal of 12 stillbirths per 1000 total births in 2030. Awareness of risk factors associated with stillbirth, preventive interventions and improved adherence to clinical guidelines during labour, and hence improved quality of care, are needed to decrease the stillbirth rate in resource-limited settings.

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.

Fetal sepsis: a cause of stillbirth

Infection is considered a leading cause of fetal death, responsible for approximately 20% of cases. Such estimates are derived from the frequency of acute histological chorioamnionitis and funisitis in cases of fetal death rather than direct detection of microorganisms in the fetal compartment. We report a case of clinically unexplained fetal death at 38 weeks of gestation in an uncomplicated pregnancy resulting in delivery of an appropriate-for-gestational-age fetus. The mother did not have any clinical signs of infection. Overwhelming bacterial invasion in multiple fetal organs, including the heart, liver, spleen, and kidneys, was observed despite the lack of evidence of maternal clinical infection. The bacteria were visualized by using standard histologic techniques (e.g. H&E/ tissue Gram stain) highlighting the value of autopsy in determining the cause of death.

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

The Global Network Maternal Newborn Health Registry: a multi-country, community-based registry of pregnancy outcomes

BACKGROUND

The Global Network for Women's and Children's Health Research (Global Network) conducts clinical trials in resource-limited countries through partnerships among U.S. investigators, international investigators based in in low and middle-income countries (LMICs) and a central data coordinating center. The Global Network's objectives include evaluating low-cost, sustainable interventions to improve women's and children's health in LMICs. Accurate reporting of births, stillbirths, neonatal deaths, maternal mortality, and measures of obstetric and neonatal care is critical to determine strategies for improving pregnancy outcomes. In response to this need, the Global Network developed the Maternal Newborn Health Registry (MNHR), a prospective, population-based registry of pregnant women, fetuses and neonates receiving care in defined catchment areas at the Global Network sites. This publication describes the MNHR, including participating sites, data management and quality and changes over time.

METHODS

Pregnant women who reside in or receive healthcare in select communities are enrolled in the MNHR of the Global Network. For each woman and her offspring, sociodemographic, health care, and the major outcomes through 42-days post-delivery are recorded. Study visits occur at enrollment during pregnancy, at delivery and at 42 days postpartum.

RESULTS

From 2010 through 2018, the Global Network MNHR sites were located in Guatemala, Belagavi and Nagpur, India, Pakistan, Democratic Republic of Congo, Kenya, and Zambia. During this period at these sites, 579,140 pregnant women were consented and enrolled in the MNHR, nearly 99% of all eligible women. Delivery data were collected for 99% of enrolled women and 42-day follow-up data for 99% of those delivered. In this supplement, the trends over time and assessment of differences across geographic regions are analyzed in a series of 18 manuscripts utilizing the MNHR data.

CONCLUSIONS

Improving maternal, fetal and newborn health in countries with poor outcomes requires an understanding of the characteristics of the population, quality of health care and outcomes. Because the worst pregnancy outcomes typically occur in countries with limited health registration systems and vital records, alternative registration systems may prove to be highly valuable in providing data. The MNHR, an international, multicenter, population-based registry, assesses pregnancy outcomes over time in support of efforts to develop improved perinatal healthcare in resource-limited areas. Trial Registration The Maternal Newborn Health Registry is registered at Clinicaltrials.gov (ID# NCT01073475). Registered February 23, 2019. https://clinicaltrials.gov/ct2/show/NCT01073475.