The Burden of Placental Histopathology in Stillbirths Associated With Maternal Obesity

Placental lesions in stillbirth following the Amsterdam consensus: A systematic review and meta-analysis

Placental disorders remain one of the main causes of stillbirth. However, the lack of standardised nomenclature has significantly limited the clinical utility of placental histology. Following the Amsterdam consensus classification, which now allows proper comparisons of placenta histology across the world, we conducted the first systematic review and meta-analysis (Prospero CRD42023410469) to assess the commonest stillbirth-associated placental lesions worldwide. Eighteen studies with 3082 placentas were included. Maternal vascular malperfusion and fetal vascular malperfusion were the most prevalent placental lesions in stillbirth, and significantly more frequent in stillbirths than livebirths [OR 3.0 (95 % CI 2.0-4.5), p < 0.001 and OR 5.12 (95 % CI 3.09-8.47), p < 0.001, respectively]. However, when adjusting for gestational age, only maternal vascular malperfusion remained significant at term. Better understanding of the pathophysiology underlying placental lesions is needed to inform timely risk assessment and therapeutic interventions capable of reducing placental-related stillbirths.

Stillbirth and the placenta

Stillbirth affects a large proportion of pregnancies world-wide annually and continues to be a major public health concern. Several causes of stillbirth have been identified and include obstetrical complications, placental abnormalities, fetal malformations, infections, and medical complications in pregnancy. Placental abnormalities such as placental abruption, chorioangioma, vasa previa, and umbilical cord abnormalities have been identified as causes of death for a significant proportion of stillbirths. In the absence of placental abnormalities, the gross and histologic changes in the placenta in stillbirth are found when secondary to other etiologies. Here we describe both gross and histologic changes of the placenta that are associated with stillbirth.

Placental pathologic features in obesity

INTRODUCTION

Obesity in pregnancy is associated with adverse long-term consequences both in the mother and in offspring. Maternal obesity induces a metabolic-inflammatory state that could impact on placental function and could mediate the adverse outcomes. The purpose of this study was to compare the major placental histological characteristics of non-diabetic obese women to lean controls, focusing on uncomplicated pregnancies.

METHODS

Prospective case-control study comparing placental histopathological features between 122 non-diabetic obese women and 185 non-obese controls. The analysis was performed on overall subjects, then uncomplicated pregnancies from both groups were analyzed. Placenta pathologic findings were recorded according to standard classification.

RESULTS

Both in overall analysis and among the subset of subjects with an uncomplicated pregnancy, obese subjects had higher risks of maternal vascular malperfusion (MVM) (respectively OR=2.2, 95%CI =1.3-3.7 and OR=4.2, 95%CI=2.1-8.5), fetal vascular malperfusion (FVM) (respectively OR=6.3, 95%CI=3.1-12.5 and OR=7.2, 95%CI=3-17.2), maternal and fetal inflammatory response placental lesions and villitis (VUE) (respectively OR=2.5, 95%CI=1.1-5.6 and OR=10.8, 95%CI=3.3-35.3) compared to controls. Among uncomplicated pregnancies and after adjustment for confounders, first trimester BMI was significantly associated with overall MVM, overall FVM, maternal inflammatory, fetal inflammatory response and VUE.

DISCUSSION

Placentas from obese women showed a significantly higher risk of maternal and fetal vascular and inflammatory placental lesions, both in overall population and in the subgroup with uncomplicated pregnancies. The metabolic and inflammatory dysfunctions typical of obesity could have an impact on placental development and function, which could be a mediator of the detrimental effects of obesity on pregnancy outcome and on future health of the offspring.

Women's perception of fetal movements and perinatal outcomes: results of a prospective cohort study

BACKGROUND

Active fetal movements (AFMs) are a sign of the well-being of the baby during pregnancy and suggests the integrity of the cardiovascular, musculoskeletal, and nervous systems of the fetus. The abnormal perception of AFMs is associated with an increased risk of adverse perinatal outcomes such as stillbirth (SB) and brain damage. Several definitions of " decreased fetal movements" have been proposed, but none of them has been universally accepted. The aim of the study is to investigate the perinatal outcomes in relation to AFMs frequency and perception in term pregnancy with an ad hoc questionnaire administered to the women before delivery.

STUDY DESIGN

This was a prospective case-control study on pregnant women at term referring to the Obstetric Unit of the University Hospital of Modena, Italy, between January 2020 and March 2020. A validated questionnaire was administered to women who agreed to participate in the study. Therefore, women were subdivided into the case and control groups: cases included women who experienced adverse perinatal outcomes (APO) such as perinatal mortality (SB and early neonatal mortality), operative delivery (cesarean section or vacuum) due to fetal distress, Apgar 5' < 7, neonatal resuscitation at birth and NICU Admission, while controls were women who experienced delivery and birth without APO in the same period.

RESULTS

Seventy-seven cases and 178 controls that compiled the questionnaire were included in the analysis. Characteristics significantly associated with APO were low education (OR 1.57, CI 95% 1.11-2.22), nulliparity (OR 1.76, CI 95% 1.20-2.58), obesity (OR 1.55, CI 95% 1.10-2.17), neonatal male gender (OR 1.92 CI95% 1.33-2.78) and centile at birth (< 10° and >90°) (OR 2.77, 95%CI 2.17, 3.55). There was no association between any answer about strengths, frequency and vigor of perceived fetal movements and APO. Even any maternal perception of fetal hiccups or uterine contractions wasn't associated with APO. On the other hand, women who referred to frequent change positions during sleep (OR 1.55 CI95% 1.05-2.30) and women who snore (OR 1.43 CI95% 1.01-2.05) showed a statistically significant increase of APO.

CONCLUSIONS

Our data confirm the significant association between modifiable risk factors (such as obesity and low education) and APO. Thus, healthcare providers should be aware of the importance of intervention in reducing obesity, therefore snoring and related sleep apnea syndrome. Finally, changing position during sleep while not the perception of modified/reduced fetal movements significantly could induce the worst obstetric outcomes.

Association of maternal Body Mass Index and parity on induced labor stages

BACKGROUND

Obesity is a widespread pandemic and obstetric care must adapt to meet the needs of obese pregnant women. Little is known about the impact of Body Mass Index (BMI) on the induction of labor (IOL). Therefore, our objective was to evaluate if the duration of the first and second stages of IOL is affected by maternal BMI in nulliparous and multiparous women.

METHODS

We included singleton pregnancies at term with cephalic presentation whose labor was induced from June 2018 to December 2019. Women were divided into two groups according to pre-pregnancy BMI in normal weight and obese women.

RESULTS

A total of 668 women with IOL were included in the study, among them, 349 had a normal weight and 321 were obese. The first stage of labor was longer in obese multiparous than normal-weight women (normal weight 81.98±71.7 vs. obese 134.3±158.1 min, P=0.000), while the second stage resulted significantly shorter (normal weight 22.2±27.8 vs. obese 14.3±14.2 min, P=0.000). The total time elapsed from IOL beginning and delivery was significantly higher in obese nulliparous (normal weight 10.4±19.7 vs. obese 22.0±26.2 h, P=0.000). Operative vaginal deliveries, emergency cesarean section, and failed IOL resulted to be similar between the groups.

CONCLUSIONS

Obese multiparous women have longer first stages of labor while shorter second stages. The total time for induced obese nulliparous to reach delivery is higher than the normal weight. It might be reasonable to reconsider the partographs according to maternal BMI in case of induced labor for future obstetric practice.

Risk factors for stillbirth at term: an Italian area-based, prospective cohort study

BACKGROUND

Stillbirth at term has great emotional impact on both parents and professionals. In developed countries, efforts to identify risk factors are mandatory to plan area-specific prevention strategies.

OBJECTIVE

The aim of the study was to identify independent risk factors that contribute to stillbirth at 37 weeks' gestation or later.

STUDY DESIGN

This was an area-based, prospective cohort study on pregnancy at term with enrolled from 2014 to 2021 in Emilia-Romagna, a north Italian region. Data were retrieved from both birth certificates and the Stillbirth Surveillance system database. To identify independent risk factors, a multivariate analysis using logistic regression was performed. A descriptive analysis of the causes of stillbirth is also reported.

RESULTS

In the observation period, 246,437 babies born at term (including 260 stillbirths, giving a rate of 1.06/1000) were considered. The risk factors independently associated with stillbirth were small for gestational age babies (odds ratio, 2.58; 95% confidence interval, 1.88-3.53), pregnancy achieved though fertility treatments (odds ratio, 2.01; 95% confidence interval, 1.15-3.51), and delayed access to pregnancy services (odds ratio, 1.56; 95% confidence interval, 1.10-2.22). In multipara, the presence of a previous stillbirth (odds ratio, 3.91; 95% confidence interval, 1.98-7.72) was also associated with an increased risk for recurrence. Early- rather than late-term was an additional risk factor. The most frequent causes of death were placental and cord disorders (61/260 and 56/260, respectively). However, 28.1% of cases remain unexplained.

CONCLUSION

The risks for stillbirth at term are known early in pregnancy or could be identified through tailored antenatal management, allowing effective preventive strategies to reduce preventable cases.

Stillbirth occurrence during COVID-19 pandemic: a population-based prospective study

OBJECTIVES

Data collected worldwide on stillbirth (SB) rates during the Covid-19 pandemic are contradictory. Variations may be due to methodological differences or population characteristics. The aim of the study is to assess the changes in SB rate, risk factors, causes of death and quality of antenatal care during the pandemic compared to the control periods.

METHODS

This prospective study is based on the information collected by the Emilia-Romagna Surveillance system database. We conducted a descriptive analysis of SB rate, risk factors, causes of death and quality of cares, comparing data of the pandemic (March 2020-June 2021) with the 16 months before.

RESULTS

During the pandemic, the SB rate was 3.45/1,000 births, a value in line with the rates of previous control periods. Neonatal weight >90th centile was the only risk factor for SB that significantly changed during the pandemic (2.2% vs. 8.0%; p-value: 0.024). No significant differences were found in the distribution of the causes of death groups. Concerning quality of antenatal cares, cases evaluated with suboptimal care (5.2%) did not change significantly compared to the control period (12.0%), as well as the cases with less than recommended obstetric (12.6% vs. 14%) and ultrasound evaluations (0% vs. 2.7%).

CONCLUSIONS

During the COVID-19 pandemic, no significant differences in SB rates were found in an area that maintained an adequate level of antenatal care. Thus, eventual associations between SB rate and the COVID-19 infection are explained by an indirect impact of the virus, rather than its direct effect.

Perinatal outcomes in twin late preterm pregnancies: results from an Italian area-based, prospective cohort study

BACKGROUND

Multiple gestations represent a considerable proportion of pregnancies delivering in the late preterm (LP) period. Only 30% of LP twins are due to spontaneous preterm labor and 70% are medically indicated; among this literature described that 16-50% of indicated LP twin deliveries are non-evidence based. As non-evidence-based delivery indications account for iatrogenic morbidity that could be prevented, the objective of our observational study is to investigate first neonatal outcomes of LP twin pregnancies according to gestational age at delivery, chorionicity and delivery indication, then non evidence-based delivery indications.

METHODS

Prospective cohort study among twins infants born between 34 + 0 and 36 + 6 weeks, in Emilia Romagna, Italy, during 2013-2015. The primary outcome was a composite of adverse perinatal outcomes.

RESULTS

Among 346 LP twins, 84 (23.4%) were monochorionic and 262 (75.7%) were dichorionic; spontaneous preterm labor accounted for 85 (24.6%) deliveries, preterm prelabor rupture of membranes for 66 (19.1%), evidence based indicated deliveries were 117 (33.8%), while non-evidence-based indications were 78 (22.5%). When compared to spontaneous preterm labor or preterm prelabor rupture of membranes, pregnancies delivered due to maternal and/or fetal indications were associated with higher maternal age (p <  0.01), higher gestational age at delivery (p <  0.01), Caucasian race (p 0.04), ART use (p <  0.01), gestational diabetes (p <  0.01), vaginal bleeding (p <  0.01), antenatal corticosteroids (p <  0.01), diagnosis of fetal growth restriction (FGR) (p <  0.01), and monochorionic (p <  0.01). Two hundred twenty-six pregnancies (65.3%) had at least one fetus experiencing one composite of adverse perinatal outcome. Multivariate analysis confirmed that delivery indication did not affect the composite of adverse perinatal outcomes; the only characteristic that affect the outcome after controlling for confounding was gestational age at delivery (p <  0.01). Moreover, there was at least one adverse neonatal outcome for 94% of babies born at 34 weeks, for 73% of those born at 35 weeks and for 46% of those born at 36 weeks (p <  0.01).

CONCLUSION

Our study suggests that the decision to deliver or not twins in LP period should consider gestational age at delivery as the main determinant infants' prognosis. Delivery indications should be accurately considered, to avoid iatrogenic early birth responsible of preventable complications.

Impact of endocrine disorders on stillbirth: a prospective cohort study

OBJECTIVE

Among risk factors for SB, maternal endocrine diseases (ED), such as thyroids dysfunction and gestational diabetes mellitus (GDM), are the most frequent. This study aimed to investigate the rate of ED in a population of SB cases collected prospectively, and the relationship between these and causes of death.

METHODS

This is an area-based, prospective cohort study conducted in Emilia-Romagna, Italy between January 2014 and December 2020. Data included all cases of SB (>22 weeks).

RESULTS

From 2014 to 2020, 766 SB occurred out of a total of 232.506 births (SB rate:0.3/1000). The ED were present in 197/766 cases of SB (25.7%), respectively, 104 thyroid disease (52.8%), 74 GDM (37.5%), and 19 cases of concomitant GDM and thyroid disease (9.6%). Women who had SB associated with ED presented significantly higher mean maternal age (p < 0.001), BMI (p < 0.001), obesity (p < 0.001) and lower smoking habit (p = 0.02) respect with control group. Neonatal and placental weight of stillborn women with ED was significantly higher (p < 0.001) in respect to stillborn of the control group. Women with ED as associated condition (ReCODE classification), present significantly higher cases of SB caused by placenta pathologies (p = 0.009) namely abruptio placentae (p = 0.001) respect than control group.

CONCLUSIONS

ED was more frequent in older and obese women experiencing SB. The main cause of death was abruptio placentae. This information can be helpful when counseling mothers with ED and planning antenatal management to prevent SB.

Maternal Vascular Lesions in the Placenta Predict Vascular Impairments a Decade After Delivery

Women with adverse pregnancy outcomes later experience excess hypertension and cardiovascular disease, but how the events are linked is unknown. Examination of the placenta may provide clues to vascular impairments after delivery. Maternal vascular malperfusion lesions (MVMs) were abstracted from clinical reports, validated and characterized using clinical guidelines and severity score. A total of 492 women (170 with MVMs and 322 without MVMs) participated in a study visit 8 to 10 years after delivery to assess blood pressure, cardiometabolic factors, and sublingual microvascular features using sidestream dark field imaging. Covariates included age, race, adverse pregnancy outcomes (preeclampsia, small for gestational age, and preterm birth), and health behaviors. Women with versus without MVM had a distinct sublingual microvascular profile comprised of (1) lower microvascular density (-410 μm/mm², P=0.015), (2) higher red blood cell filling as a marker of perfusion (2%, P=0.004), and (3) smaller perfused boundary region (-0.07 µm, P=0.025) as a measure of glycocalyx integrity, adjusted for covariates including adverse pregnancy outcomes. Women with MVM also had higher adjusted diastolic blood pressure (+2.6 mm Hg, P=0.021), total and LDL (low-density lipoprotein)-cholesterol (+11.2 mg/dL, P=0.016; +8.7 mg/dL, P=0.031). MVM associations with subsequent cardiovascular measures did not vary by type of adverse pregnancy outcome, except among women with preterm births where blood pressure was higher only among those with MVM. Results were similar when evaluated as MVM severity. A decade after delivery, women with placental vascular lesions had an adverse cardiovascular profile comprised of microvascular rarefaction, higher blood pressure and more atherogenic lipids. Placental histopathology may reveal a woman's early trajectory toward subsequent vascular disease.

Cause-Specific Stillbirth and Neonatal Death According to Prepregnancy Obesity and Early Gestational Weight Gain: A Study in the Danish National Birth Cohort

Maternal obesity is associated with impaired fetal and neonatal survival, but underlying mechanisms are poorly understood. We examined how prepregnancy BMI and early gestational weight gain (GWG) were associated with cause-specific stillbirth and neonatal death. In 85,822 pregnancies in the Danish National Birth Cohort (1996–2002), we identified causes of death from medical records for 272 late stillbirths and 228 neonatal deaths. Prepregnancy BMI and early GWG derived from an early pregnancy interview and Cox regression were used to estimate associations with stillbirth or neonatal death as a combined outcome and nine specific cause-of-death categories. Compared to women with normal weight, risk of stillbirth or neonatal death was increased by 66% with overweight and 78% with obesity. Especially deaths due to placental dysfunction, umbilical cord complications, intrapartum events, and infections were increased in women with obesity. More stillbirths and neonatal deaths were observed in women with BMI < 25 and low GWG. Additionally, unexplained intrauterine death was increased with low GWG, while more early stillbirths were seen with both low and high GWG. In conclusion, causes of death that relate to vascular and metabolic disturbances were increased in women with obesity. Low early GWG in women of normal weight deserves more clinical attention.

Placental decidual arteriopathy and vascular endothelial growth factor A (VEGF-A) expression among women with and without HIV

BACKGROUND

Women with HIV (WHIV) are at higher risk of adverse birth outcomes. Proposed mechanisms for the increased risk include placental arteriopathy (vasculopathy) and maternal vascular malperfusion (MVM) due to antiretroviral therapy (ART) and medical comorbidities. However, these features and their underlying pathophysiologic mechanisms have not been well characterized in WHIV.

METHODS

We performed gross and histologic examination and immunohistochemistry staining for vascular endothelial growth factor A (VEGF-A), a key angiogenic factor, on placentas from women with one or more MVM risk factors including: weight <5 th percentile, histologic infarct or distal villous hypoplasia, nevirapine-based ART, hypertension, and pre-eclampsia/eclampsia during pregnancy. We compared pathologic characteristics by maternal HIV serostatus.

RESULTS

A total of 27/41 (66%) placentas assessed for VEGF-A were from WHIV. Mean maternal age was 27 years. Among WHIV, median CD4 T-cell count was 440 cells/mm 3 and HIV viral load was undetectable in 74%. Of VEGF-A stained placentas, both decidua and villous endothelium tissue layers were present in 36 (88%). VEGF-A was detected in 31/36 (86%) with decidua present, and 39/40 (98%) with villous endothelium present. There were no differences in VEGF-A presence in any tissue type by maternal HIV serostatus (P=0.28-1.0). MVM was more common in placentas selected for VEGF-A staining (51 versus 8%, P<0.001).

CONCLUSIONS

VEGF-A immunostaining was highly prevalent, and staining pattern did not differ by maternal HIV serostatus among those with MVM risk factors, indicating the role of VEGF-A in placental vasculopathy may not differ by maternal HIV serostatus.