Aspirin use during pregnancy and hypoxia-related placental pathology

In utero aspirin exposure and child neurocognitive development: A propensity score-matched analysis

OBJECTIVE

To evaluate the association between a short-period, high-dose in utero aspirin exposure and child neurocognitive development.

DESIGN

A propensity score-matched analysis of a multicentre prospective cohort study.

SETTING

The US Collaborative Perinatal Project (1959-1976).

POPULATION

A total of 50 565 singleton live births with maternal information.

METHODS

We performed a propensity score matching to balance maternal characteristics between women with and without aspirin exposure. Inverse probability-weighted marginal structural models were used to estimate associations between aspirin exposure and child neurocognitive assessments.

MAIN OUTCOME MEASURES

Child neurocognitive development was assessed using the Bayley Scales at 8 months, the Stanford Binet Intelligence Scale at 4 years, and the Wechsler Intelligence Scale and Wide-Range Achievement Test (WRAT) at 7 years.

RESULTS

Children exposed to aspirin in utero were associated with an 8%-16% reduced risk of having suspect/abnormal or below-average scores in most neurocognitive assessments. A trend of lower risks of having suspect/abnormal or below-average scores was further observed in children with in utero aspirin exposure for more than 7 days, particularly on Bayley Mental (relative risk [RR] 0.82, 95% CI 0.74-0.92), WRAT Reading (RR 0.88, 95% CI 0.78-0.98) and WRAT Arithmetic tests (RR 0.76, 95% CI 0.66-0.86). This association was mainly observed in the second trimester of pregnancy.

CONCLUSIONS

In utero aspirin exposure was associated with improved child neurocognitive development in a prospective cohort study. Further studies are warranted to evaluate the impact of long-period and low-dose in utero aspirin exposure on child short- and long-term neurodevelopment.

Maternal Vascular Malperfusion and Anatomic Cord Abnormalities Are Prevalent in Pregnancies With Fetal Congenital Heart Disease

OBJECTIVE

Impairments in the maternal-fetal environment are associated with adverse postnatal outcomes among infants with congenital heart disease. Therefore, we sought to investigate placental anomalies as they related to various forms of fetal congenital heart disease (FCHD).

METHODS

We reviewed the placental pathology in singleton pregnancies with and without FCHD. FCHD was divided into separate categories (transposition physiology, obstructive left, obstructive right, biventricular without obstruction, and others). Exclusion criteria included other prenatally known structural malformations and/or aneuploidy. The significance threshold was set at p < 0.05 or False Discovery rate q < 0.05 when multiple tests were performed.

RESULTS

The cohort included 215 FCHD and 122 non-FCHD placentas. FCHD placentas showed increased rates of maternal vascular malperfusion (24% vs. 5%, q < 0.001) and cord anomalies (27% vs. 1%, q < 0.001). Placentas with fetal TGA demonstrated a lower rate of hypoplasia when compared with other FCHD types (1/39 vs. 51/176, Fisher's exact p = 0.015).

CONCLUSION

Placental maternal vascular malperfusion is increased in FCHD. The prevalence of vascular malperfusion did not differ by FCHD type, indicating that CHD type does not predict the likelihood of placental vascular dysfunction. Further investigation of the placental-fetal heart axis in FCHD is warranted given the importance of placental health.

Pregnancy complications and placental histology following embryo transfer with a thinner endometrium

STUDY QUESTION

Are deliveries following IVF with a thinner endometrium associated with adverse perinatal outcomes and placental findings?

SUMMARY ANSWER

Live births following IVF with a thinner endometrium are associated with an increased rate of placental-mediated obstetric complications and lower birthweight, while the placentas are notable for gross anatomical and histological malperfusion lesions.

WHAT IS KNOWN ALREADY

Past studies have noted a higher rate of adverse outcomes on deliveries following IVF with a thinner endometrium, mainly placental-associated complications. However, no study to date has investigated placental histopathology in such cases.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study of 1057 deliveries following IVF, between 2009 and 2017. All placentas were sent to pathology irrelevant of pregnancy complication status, per protocol at our institution.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Live singleton births from a tertiary university hospital after IVF were compared between patients for whom embryo transfer was performed with an endometrium <9 mm (thinner endometrium group) and patients with an endometrium ≥9 mm (control group). Placental pathologic findings were categorized according to the Amsterdam Placental Workshop Group Consensus. Outcomes were placental findings, including anatomic, inflammatory, vascular malperfusion and villous maturation lesions, as well as obstetric and perinatal outcomes. Continuous and categorical variables were compared as appropriate, and multivariate regression and linear analyses were employed to control for confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

A total 292 cases in the thinner endometrium group, and 765 in the control group were compared. Maternal demographics were non-significant between the groups, except for main fertility indication was more commonly diminished reserve in patients with a thinner endometrium and less commonly male factor, P = 0.003. Higher rates of fresh transfers were noted in the control group, while the thinner endometrium group was notable for higher rates of blastocyte transfers. After adjustment for confounders, deliveries in the thinner endometrium group were associated with an overall higher rate of main placental-mediated complications, 22.9% versus 15.2%, P = 0.003, and significantly lower birthweight, β -100.76 g (-184.4-(-17.0)). Placentas in the thinner endometrium group were notable for reduced thickness and a higher rate of bilobated placentas. Placental histology in the thinner endometrium group demonstrated a higher rate of maternal malperfusion lesions.

LIMITATIONS, REASONS FOR CAUTION

The study was limited by its retrospective design and lack of data regarding prior uterine surgery. In addition, sample size was limited for detection of differences in outcomes of rarer occurrence and for analysis as per a stricter definition of thin endometrium.

WIDER IMPLICATIONS OF THE FINDINGS

Excess obstetric risks should be taken into consideration while planning an embryo transfer with a thinner endometrium. Further studies are needed to assess the yield of cycle cancellation and the effect of potential preventive measures such as Micropirin treatment.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was used and the authors report no conflicting interests.

TRIAL REGISTRATION NUMBER

N/A.

Placental characteristics and risks of maternal mortality 50 years after delivery

INTRODUCTION

Adverse pregnancy outcomes such as preterm delivery and preeclampsia are associated with a higher maternal risk for subsequent cardiovascular disease (CVD) and all-cause mortality. While such pregnancy conditions are related to abnormal placentation, little research has investigated whether pathologic placental measures could serve as a risk factor for future CVD mortality in mothers.

METHODS

Longitudinal study of 33,336 women from the Collaborative Perinatal Project (CPP; 1959-1966) linked to mortality information through December 2016. Pathologists took extensive morphological and histopathological measures. Apart from assessing associations with morphological features, we derived an overall composite score and specific inflammation-related, hemorrhage-related, and hypoxia-related pathologic placenta index scores. Cox regression estimated hazard ratios (HR) and 95% confidence intervals (CI) for mortality adjusting for covariates.

RESULTS

Thirty-nine percent of women died with mean (standard deviation, SD) time to death of 39 (12) years. Mean (SD) placental weight and birthweight were 436 g (98) and 3156 g (566), respectively. Placenta-to-birthweight ratio was associated with all-cause mortality (adjusted HR 1.03: 1.01, 1.05 per SD in ratio). In cause-specific analyses, it was significantly associated with respiratory (HR 1.06), dementia (HR: 1.10) and liver (HR 1.04) related deaths. CVD, cancer, diabetes and kidney related deaths also tended to increase, whereas infection related deaths did not (HR 0.94; 0.83, 1.06). Placental measures of thickness, diameters, and histopathological measures grouped by inflammatory, hemorrhagic, or hypoxic etiology were not associated with mortality.

DISCUSSION

Placental weight in relation to birthweight was associated with long-term maternal mortality but other histopathologic or morphologic features were not.

Choosing placental hypoxic-ischemic measures that have clinical implications in child development and diseases

PURPOSE

Placental hypoxic-ischemic pathology is one of the common causes for adverse outcomes. But there is no commonly accepted evaluation system on specific morphological and histopathological measures of the placenta.

OBJECTIVE

This study aims to systematically select several core placental hypoxic-ischemic measures that have a high prognostic relevance to child health.

METHODS

We used data from the Collaborative Perinatal Project, a multicenter prospective cohort study that recruited over 55,000 pregnant women and followed their offspring to 7 years old. Women who had information on placental pathology and child outcomes were included. 57 placental measures considered to be relevant to hypoxia-ischemia were selected. Apgar score, intelligence quotient, preeclampsia, birth weight and subclinical neurology injuries were chosen as outcomes. The least absolute shrinkage and selection operator (LASSO) procedure as well as training and testing methods were used to select a more efficient and simpler placental hypoxic-ischemic measures that may have clinical implications.

RESULTS

Of the 57 measures, 7 were selected as candidates by LASSO. Based on the training and testing methods, we retained placental measures with a higher odds ratio of child morbidity. We further narrowed down to four measures that had the highest prognostic relevance. They were: short cord length (ΣOR = 8.51), calcification of cut surface (ΣOR = 8.31), opaque membranes (ΣOR = 5.26), Hofbauer cells in terminal villi (ΣOR = 4.69).

CONCLUSIONS

Our four-measure system is relatively simple and closely related to the child health. It may be used as a novel placental hypoxic-ischemic evaluation criterion, and function as the first line tool for future research.

Histologic Chorioamnionitis in Pregnancies Complicated by Preeclampsia and the Effect on Neonatal Outcomes

Histological chorioamnionitis (HC) is a common placental finding that represents acute/chronic inflammation and can affect neonatal outcomes. We aimed to examine the effect of HC on neonatal outcomes in pregnancies complicated by preeclampsia. All pregnancies with the diagnosis of preeclampsia at 24-42 weeks between 2008 and 2019 were reviewed. Placental lesions were classified according to the "Amsterdam" criteria. Composite adverse neonatal outcome included ≥1 early complication. Maternal and neonatal outcomes were compared between cases with and without HC. Multivariable regression analysis was performed to identify independent associations with adverse neonatal outcome. Compared to preeclampsia without HC (n=517), preeclampsia with HC (n=55) was characterized by a more advanced gestational age (p<0.001) and a higher rate of nulliparity (p=0.02). Diabetes was more prevalent in preeclampsia without HC (p=0.039) as was a history of previous preeclampsia (p=0.048). Neonates in the preeclampsia with HC group had higher rates of adverse neonatal outcome (p<0.001) and Apgar scores <7 at 5 min (p=0.034) despite a higher birthweight (p=0.005). Preeclampsia without HC was associated with smaller placentas and a higher rate of placental maternal vascular malperfusion lesions (p=0.014 and p<0.001 respectively). By multivariate analysis, gestational age and HC were independently associated with adverse neonatal outcome (aOR 0.88 95% CI 0.76-0.96, and aOR 1.33, 95% CI 1.11-3.09, respectively). In preeclampsia, concomitant HC was associated with adverse neonatal outcome despite a more advanced gestational age and higher neonatal birthweight. This inflammatory mechanism probably plays a role in a more severe subgroup of preeclampsia cases, causing an additional risk for the developing fetus.

Association between Placental Inflammatory Pathology and Offspring Neurodevelopment at 8 Months and 4 and 7 Years of Age

OBJECTIVE

To examine whether placental inflammatory pathology is associated with subsequent child neurodevelopment.

STUDY DESIGN

We used the data of US Collaborative Perinatal Project cohort study. Placentas were examined by pathologists and child neurodevelopment was evaluated at 8 months and 4 and 7 years of age. Multivariable logistic regression modelling was used to assess the association. A mediation analysis was used to evaluate whether the association was mediated through shorter gestational age.

RESULTS

Multivariable analysis after adjusting for confounders showed that placental inflammatory pathology was significantly associated with low Bayley motor (adjusted OR (aOR), 2.15; 95% CI, 1.50-3.06) and mental scales (aOR, 1.51; 95% CI, 1.05-2.17) at 8 months and an IQ of 70-84 (aOR, 1.13; 95% CI, 1.01-1.26) at 4 years of age. The association diminished at 7 years of age (IQ of <70, aOR 1.20 [95% CI, 0.97-1.48]; IQ of 70-79, aOR 1.03 [95% CI, 0.89-1.18]). The mediation analysis demonstrated that associations between placental inflammatory pathology and development were primarily due to direct effects of placental inflammatory pathology rather than indirect effects of shorter gestational age.

CONCLUSIONS

Placental inflammation was associated with adverse offspring neurodevelopment up to 4 years of age.

Pathophysiological implications of hypoxia in human diseases

Oxygen is essentially required by most eukaryotic organisms as a scavenger to remove harmful electron and hydrogen ions or as a critical substrate to ensure the proper execution of enzymatic reactions. All nucleated cells can sense oxygen concentration and respond to reduced oxygen availability (hypoxia). When oxygen delivery is disrupted or reduced, the organisms will develop numerous adaptive mechanisms to facilitate cells survived in the hypoxic condition. Normally, such hypoxic response will cease when oxygen level is restored. However, the situation becomes complicated if hypoxic stress persists (chronic hypoxia) or cyclic normoxia-hypoxia phenomenon occurs (intermittent hypoxia). A series of chain reaction-like gene expression cascade, termed hypoxia-mediated gene regulatory network, will be initiated under such prolonged or intermittent hypoxic conditions and subsequently leads to alteration of cellular function and/or behaviors. As a result, irreversible processes occur that may cause physiological disorder or even pathological consequences. A growing body of evidence implicates that hypoxia plays critical roles in the pathogenesis of major causes of mortality including cancer, myocardial ischemia, metabolic diseases, and chronic heart and kidney diseases, and in reproductive diseases such as preeclampsia and endometriosis. This review article will summarize current understandings regarding the molecular mechanism of hypoxia in these common and important diseases.

Pregnancy outcomes in correlation with placental histopathology in subsequent pregnancies complicated by fetal growth restriction

OBJECTIVE

In attempt to shed new light on the etiopathogenesis of fetal growth restriction (FGR) we aimed to compare pregnancy outcomes and placental histopathology in cases of first vs. subsequent FGR occurrence.

STUDY DESIGN

Pregnancy and placental reports of FGR pregnancies (defined by birth weight <10th percentile), born between 2008 and 2018 were reviewed. Included only cases with recurrent FGR, in two consecutive pregnancies, thus each subject served as her own control in two FGRs consecutive pregnancies. Neonatal outcome and placental histopathology were compared between the first FGR delivery (first FGR group) and the subsequent FGR delivery (subsequent FGR group). Composite adverse neonatal outcome was defined as one or more early neonatal complications.

RESULTS

Included in the study a total of 96 cases with recurrence of FGR pregnancies. Placentas from the first FGR group were characterized by higher rate of maternal vascular malperfusion (MVM) lesions as compared with the subsequent FGR group (71.8% versus 55.2%, respectively, p = 0 .02). Adverse neonatal outcome was more prevalent in the first FGR group as compared to the recurrent FGR group (41.6% versus 25%, respectively, p = 0.02). After controlling for confounders, using multivariate regression analysis, placental MVM lesions (aOR = 1.36, 95% CI = 1.12-1.45) and composite adverse neonatal outcome (aOR = 1.18 95% CI = 1.09-1.55) were found to be independently associated with the first FGR group.

CONCLUSION

First event of FGR is associated with a higher rate of placental MVM lesions and adverse neonatal outcome as compared to FGR in subsequent pregnancies.