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

The utility of complete blood parameter indices to predict stillbirths

OBJECTIVE

In this study, we aimed to investigate the relationship between unexplained stillbirth (SB) cases and the complete blood parameter indices and we compared them with uncomplicated healthy cases.

METHODS

Patients diagnosed with unexplained SB cases in a tertiary center between 2019-2022 were included in this retrospective case-control study. The gestational age threshold for SBs was accepted as births after the 20th week of pregnancy. Consecutive patients with no adverse obstetric outcomes were accepted as the control group. Patients' complete blood parameter results at the time of the first admission to the hospital until 14 weeks were labeled as "1'' and at the time of delivery were labeled as "2'' and recorded. As inflammatory parameters, neutrophile-lymphocyte ratio, derivated neutrophile-lymphocyte ratio, platelet-lymphocyte ratio, lymphocyte-monocyte ratio (LMR), and hemoglobin-lymphocyte ratio (HLR) were calculated from complete blood results and recorded.

RESULTS

There were statistically significant differences between the groups' LMR1 (p = .040). Additionally, whereas HLR1 of the study group was 0.693 (0.38-2.72), it was 0.645 (0.15-1.82) in the control group (p = .026). However, the HLR2 of the study group was significantly lower than the control group (p = .021).

CONCLUSION

Necessary precautions such as fetal biophysical profile examination can be taken more frequently in the antenatal follow-up in patients considered to be at high risk of SB by using HLR. It is a novel marker that can be easily accessible and calculated from the complete blood parameters.

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.

Association of white blood cell count after operative vaginal delivery with maternal adverse outcome: A retrospective cohort study

BACKGROUND

The white blood cell count is often used to assess the maternal condition after an operative vaginal delivery. However, it remains unknown whether the maternal white blood cell count on the day after delivery is associated with sequential maternal adverse outcomes, especially infectious complications. The aim of this study was to investigate the association between maternal white blood cell count on the day after operative vaginal delivery and sequential maternal adverse events.

METHODS

The study was a retrospective cohort study using the Medical Data Vision claims database containing administrative claims data, discharge abstracts, and laboratory values in Japan. We identified all patients who underwent operative vaginal delivery with data on maternal white blood cell count from December 2011 to November 2020. The main composite outcome was maternal adverse outcomes, comprising additional treatment for maternal injuries, postpartum intravenous antibiotic use, and intensive care unit use during hospitalization. We conducted a restricted cubic spline analysis to investigate the nonlinear association between white blood cell count and the primary outcome.

RESULTS

There were 485 eligible patients including 73 patients with occurrence of the primary outcome. The median (interquartile range) white blood cell count on the day after delivery in all eligible women was 15,170 (12,610-18,300)/mL. In the restricted cubic spline analysis, there was no significant association of white blood cell count with the primary outcome.

CONCLUSION

White blood cell count on the day after operative vaginal delivery was not significantly associated with maternal adverse outcomes during hospitalization.

Clinical analysis of diabetes in pregnancy with stillbirth

We analyzed the clinical characteristics of patients with diabetes in pregnancy (DIP) associated with stillbirth and explored strategies to reduce its incidence. We retrospectively analyzed 71 stillbirths associated with DIP (group A) and 150 normal pregnancies (group B) during 2009 to 2018. The incidence of the following was higher in group A (P < .05): hypertensive disorders (38.03% vs 6.00%), placenta previa (14.08% vs 2.67%), placental abruption (5.63% vs 0.67%), fetal malformation (8.45% vs 0.67%), fasting plasma glucose (FPG) ≥ 7.0 mmol/L (46.48% vs 0.67%), 2-h postprandial plasma glucose ≥ 11.1 mmol/L (57.75% vs 6.00%), HbA1c ≥ 6.5% (63.38% vs 6.00%), and polyhydramnios (11.27% vs 4.67). The incidence of oligohydramnios (4.23% vs 6.67%) was lower in group A than in group B (P < .05). According to the gestational age at the time of stillbirth, Group-A cases were subgrouped into miscarriages (20-27+6 weeks), premature deliveries (28-36+6 weeks), and full-term deliveries (≥37 weeks). Age, parity, and DIP type did not differ among the subgroups (P > .05). Among patients with DIP, antenatal FPG, 2-h postprandial plasma glucose, and HbA1c were significantly associated with stillbirth (P < .05). Stillbirth was first detected at 22 weeks and typically occurred at 28-36+6 weeks. DIP was associated with a higher incidence of stillbirth, and FPG, 2-h postprandial plasma glucose, and HbA1c were potential indicators of stillbirth in DIP. Age (odds ratio [OR]: 2.21, 95% confidence interval [CI]: 1.67-2.74), gestational hypertension (OR: 3.44, 95% CI: 2.21-4.67), body mass index (OR: 2.86, 95% CI: 1.95-3.76), preeclampsia (OR: 2.29, 95% CI: 1.45-3.12), and diabetic ketoacidosis (OR: 3.99, 95% CI: 1.22-6.76) were positively correlated with the occurrence of stillbirth in DIP. Controlling perinatal plasma glucose, accurately detecting and managing comorbidities/complications, and timely termination of pregnancy can reduce the incidence of stillbirths associated with DIP.

Periconceptional biomarkers for maternal obesity: a systematic review

Periconceptional maternal obesity is linked to adverse maternal and neonatal outcomes. Identifying periconceptional biomarkers of pathways affected by maternal obesity can unravel pathophysiologic mechanisms and identify individuals at risk of adverse clinical outcomes. The literature was systematically reviewed to identify periconceptional biomarkers of the endocrine, inflammatory and one-carbon metabolic pathways influenced by maternal obesity. A search was conducted in Embase, Ovid Medline All, Web of Science Core Collection and Cochrane Central Register of Controlled Trials databases, complemented by manual search in PubMed until December 31^st, 2020. Eligible studies were those that measured biomarker(s) in relation to maternal obesity, overweight/obesity or body mass index (BMI) during the periconceptional period (14 weeks preconception until 14 weeks post conception). The ErasmusAGE score was used to assess the quality of included studies. Fifty-one articles were included that evaluated over 40 biomarkers. Endocrine biomarkers associated with maternal obesity included leptin, insulin, thyroid stimulating hormone, adiponectin, progesterone, free T4 and human chorionic gonadotropin. C-reactive protein was associated with obesity as part of the inflammatory pathway, while the associated one-carbon metabolism biomarkers were folate and vitamin B12. BMI was positively associated with leptin, C-reactive protein and insulin resistance, and negatively associated with Free T4, progesterone and human chorionic gonadotropin. Concerning the remaining studied biomarkers, strong conclusions could not be established due to limited or contradictory data. Future research should focus on determining the predictive value of the optimal set of biomarkers for their use in clinical settings. The most promising biomarkers include leptin, adiponectin, human chorionic gonadotropin, insulin, progesterone and CRP.

Etiology and evaluation of stillbirth in patients with obesity

OBJECTIVE

Maternal obesity is a risk factor for stillbirth, but whether or not the etiology of stillbirth differs in gravidas with and without obesity is unknown. We categorized stillbirths in a contemporary cohort to test the hypothesis that the etiology of stillbirth is different in gravidas with and without obesity.

METHODS

This retrospective cohort study included all gravidas with a stillbirth ≥20 weeks' gestation between 2010 and 2017 and a normal mid-trimester anatomic survey by ultrasound assessment at a large academic institution. Pregnancies were excluded if delivery data were unavailable, a multifetal gestation was present, or there was an antenatally diagnosed fetal structural or genetic anomaly. Our primary exposure was maternal obesity, defined as a body mass index (BMI) ≥ 30 kg/m² at the time of anatomic survey. Our primary outcome was stillbirth etiology, as classified by the initial causes of fetal death tool from the Stillbirth Collaborative Research Network and includes maternal, obstetric, hematologic, fetal, infectious, placental, other, or unexplained categories. Our secondary outcomes included the evaluation performed on each stillbirth, compliance with the recommended stillbirth evaluation by the American College of Obstetricians and Gynecologists (ACOG), and the percentage of abnormal results for each of the tests ordered for stillbirth evaluation.

RESULTS

Of 118 stillbirths meeting the inclusion criteria, 44 (37.3%) occurred in gravidas with obesity and 74 (62.7%) were in patients without obesity. An obstetric complication was the most commonly identified etiology for stillbirth, found in 40.9% of cases with obesity versus in 29.7% of cases without obesity (aOR 1.09, 95% CI 0.47-2.66). The likelihood of any specific etiology of stillbirth was not significantly different in gravidas of the two weight groups, after controlling for confounders. However, assignment to the unexplained stillbirth category was significantly less common in women with obesity, compared to those without obesity (aOR 0.18, 95% CI 0.05-0.67). There was no difference in testing performed on each stillbirth between the groups. Compliance with the ACOG-recommended diagnostic evaluation for stillbirth was similar in the two groups but was only performed in 10.2% of all cases of stillbirth. Placental pathology was the test most likely to yield an abnormal result in both groups, but the percentage of abnormal results for this and all other tests was the same in the presence and absence of obesity.

CONCLUSION

There is no specific etiology of stillbirth seen in gravidas with obesity, compared to those without obesity, after controlling for maternal confounders. We surmise that the evaluation recommended for stillbirth assessment in the general population is appropriate for stillbirth evaluation in gravidas with obesity. Testing pursued was similar between groups, but compliance with ACOG recommendations for testing after stillbirth was deficient in the cohort. Future work should aim to identify and address barriers to completing the recommended stillbirth evaluation.

Altered Offspring Immunity in Maternal Parasitic Infections

Maternal infection during pregnancy is known to alter the development and function of offspring's immune system, leading to inappropriate immune responses to common childhood infections and immunizations. Although this is an expanding field, maternal parasitic infections remain understudied. Millions of women of reproductive age are currently at risk for parasitic infection, whereas many pregnant, chronically infected women are excluded from mass drug administration due partially to a lack of resources, as well as fear of unknown adverse fetal developmental outcomes. In areas endemic for multiple parasitic infections, such as sub-Saharan Africa, there are increased rates of morbidity and mortality for various infections during early childhood in comparison with nonendemic areas. Despite evidence supporting similar immunomodulatory effects between various parasite species, there is no clear mechanistic understanding of how maternal infection reprograms offspring immunity. This brief review will compare the effects of selected maternal parasitic infections on offspring immunity.

Racial Disparities in Stillbirth Risk Factors among non-Hispanic Black Women and non-Hispanic White Women in the United States

INTRODUCTION

Historically, stillbirth risk factors are more prevalent among non-Hispanic Black women than non-Hispanic White women, including age < 20, lower formal educational attainment, prepregnancy obesity, smoking, hypertension, diabetes, short interpregnancy interval, small for gestational age newborn, late prenatal care, and previous cesarean birth. We examined whether these disparities have changed since 2011 and identified a group of risk factors that differed between Black women and White women when accounting for correlations among variables.

METHODS

In a random sample of 315 stillbirths from the National Center for Health Statistics' 2016 fetal death data, Black women and White women were compared for each risk factor using t-tests or chi-square tests. Variables with p ≤ .20 were analyzed using multivariate analysis of variance.

RESULTS

In this sample, Black women experiencing stillbirth were less likely to have a Bachelor's degree (12.94% vs. 28.49%, p = .04), and more likely to be obese (44.5% vs. 29.1%, p = .01) than White women. Multivariate analysis accounting for correlations among variables showed a group of risk factors that differed between Black women and White women: age < 20, lower education, prepregnancy obesity, hypertension (chronic and pregnancy-associated), nulliparity before stillbirth, and earlier gestation.

CLINICAL IMPLICATIONS

Less formal education, obesity, age <20, hypertension, chronic and pregnancy-associated, nulliparity, and earlier gestation are important to consider in multilevel stillbirth prevention interventions to decrease racial disparity in stillbirth. Respectfully listening to women and taking their concerns seriously is one way nurses and other health care providers can promote equity in health outcomes for childbearing women.

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

OBJECTIVE

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

DESIGN

Prospective observational study.

SETTING

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

POPULATION

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

TWEETABLE ABSTRACT

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

Maternal obesity and stillbirth at term; placental pathology-A case control study

OBJECTIVE

The aim was to explore the potential role of the placenta for the risk of stillbirth at term in pregnancies of obese women.

METHODS

This was a case-control study comparing placental findings from term stillbirths with placental findings from live born infants. Cases were singleton term stillbirths to normal weight or obese women, identified in the Stockholm stillbirth database, n = 264 and n = 87, respectively. Controls were term singletons born alive to normal weight or obese women, delivered between 2002-2005 and between 2018-2019. Placentas were compared between women with stillborn and live-born infants, using logistic regression analyses.

RESULTS

A long and hyper coiled cord, cord thrombosis and velamentous cord insertion were stronger risk factors for stillbirth in obese women compared to normal weight women. When these variables were adjusted for in the logistic regression analysis, also adjusted for potential confounders, the odds ratio for stillbirth in obese women decreased from 1.89 (CI 1.24-2.89) to 1.63 (CI 1.04-2.56).

CONCLUSION

Approximately one fourth of the effect of obesity on the risk of stillbirth in term pregnancies is explained by umbilical cord associated pathology.

The Influence of Obesity and Associated Fatty Acids on Placental Inflammation

PURPOSE

Maternal obesity, affecting nearly 1 in 4 pregnancies, is associated with increased circulating saturated fatty acids, such as palmitate. These fatty acids are implicated in placental inflammation, which may in turn exacerbate both maternal-fetal tolerance and responses to pathogens, such as group B Streptococcus. In this review, we address the question, "How do obesity and associated fatty acids influence placental inflammation?"

METHODS

In this narrative review, we searched PubMed and Google Scholar using combinations of the key words placental inflammation or pregnancy and lipids, fatty acids, obesity, palmitate, or other closely related search terms. We also used references found within these articles that may have been absent from our original search queries. We analyzed methods and key results of these articles to compare and contrast their findings, which were occasionally at odds with each other.

FINDINGS

Although obesity can be studied as a whole, complex phenomena with in vivo mouse models and human samples from patients with obesity, in vitro modeling often relies on the treatment of cells or tissues with ≥1 fatty acids and occasionally other compounds (eg, glucose and insulin). We found that palmitate, most commonly used in vitro to recreate hallmarks of obesity, induces apoptosis, oxidative stress, mitochondrial dysfunction, autophagy defects, and inflammasome activation in many placental cell types. We compare this to in vivo models of obesity wherever possible. We found that obesity as a whole may have more complex regulation of these phenomena (apoptosis, oxidative stress, mitochondrial dysfunction, autophagy defects, and inflammasome activation) compared with in vitro models of fatty acid treatment (primarily palmitate) because of the presence of unsaturated fatty acids (ie, oleate), which may have anti-inflammatory effects.

IMPLICATIONS

The interaction of unsaturated fatty acids with saturated fatty acids may ameliorate many inflammatory effects of saturated fatty acids alone, which complicates interpretation of in vitro studies that focus on a particular fatty acid in isolation. This complication may explain why certain studies of obesity in vivo have differing outcomes from studies of specific fatty acids in vitro.