Mild to Moderate, but Not Minimal or Severe, Acute Histologic Chorioamnionitis or Intra-Amniotic Inflammation Is Associated with a Decrease in Respiratory Distress Syndrome of Preterm Newborns without Fetal Growth Restriction

Association of BNT162b2 SARS-CoV-2 vaccination during pregnancy with postnatal outcomes in premature infants

AIM

The effect of COVID-19 vaccine given during pregnancy on premature infants is unknown. This study aims to determine the association between maternal COVID-19 vaccine with postnatal outcome in premature infants.

METHODS

This is a single-centre retrospective case-control study of infants born before 35 weeks gestation to mothers who received SARS-CoV-2 vaccine during pregnancy compared with infant born to non-vaccinated mothers.

RESULTS

A total of 78 infants in each group were included. Infants in the vaccinated group had less respiratory distress syndrome (RDS) (p = 0.02) and less need for respiratory support (p = 0.002), and maternal vaccine had a protective effect on RDS [adjustable OR 0.38 (0.17-0.85)]. Vaccination during the first compared to the second trimester was associated with earlier gestational age (32.3 ± 2.1 vs. 33.3 ± 1.1 weeks, p = 0.03).

CONCLUSION

We demonstrated that maternal SARS-CoV-2 vaccine is not associated with postnatal adverse effect in premature infants and potentially has a protective effect on RDS. Earlier gestational age among the infants born to mothers who received COVID-19 vaccine during the first trimester did not translate to higher rate of postnatal complications. These findings might suggest that COVID-19 vaccine is safe in high-risk pregnancies, but timing of administration should be considered. Further studies are needed to confirm our findings and the biological mechanism.

The histologic fetal inflammatory response and neonatal outcomes: systematic review and meta-analysis

OBJECTIVE

This study aimed to investigate the prognostic role of concomitant histological fetal inflammatory response with chorioamnionitis on neonatal outcomes through a systematic review and meta-analysis of existing literature.

DATA SOURCES

The primary search was conducted on October 17, 2021, and it was updated on May 26, 2023, across 4 separate databases (MEDLINE, the Cochrane Central Register of Controlled Trials, Embase, and Scopus) without using any filters.

STUDY ELIGIBILITY CRITERIA

Observational studies reporting obstetrical and neonatal outcomes of infant-mother dyads with histological chorioamnionitis and histological fetal inflammatory response vs infant-mother dyads with histological chorioamnionitis alone were eligible. Studies that enrolled only preterm neonates, studies on neonates born before 37 weeks of gestation, or studies on neonates with very low birthweight (birthweight <1500 g) were included. The protocol was registered with the International Prospective Register of Systematic Reviews (registration number: CRD42021283448).

METHODS

The records were selected by title, abstract, and full text, and disagreements were resolved by consensus. Random-effect model-based pooled odds ratios with corresponding 95% confidence intervals were calculated for dichotomous outcomes.

RESULTS

Overall, 50 studies were identified. A quantitative analysis of 14 outcomes was performed. Subgroup analysis using the mean gestational age of the studies was performed, and a cutoff of 28 weeks of gestation was implemented. Among neonates with lower gestational ages, early-onset sepsis (pooled odds ratio, 2.23; 95% confidence interval, 1.76-2.84) and bronchopulmonary dysplasia (pooled odds ratio, 1.30; 95% confidence interval, 1.02-1.66) were associated with histological fetal inflammatory response. Our analysis showed that preterm neonates with a concomitant histological fetal inflammatory response are more likely to develop intraventricular hemorrhage (pooled odds ratio, 1.54; 95% confidence interval, 1.18-2.02) and retinopathy of prematurity (pooled odds ratio, 1.37; 95% confidence interval, 1.03-1.82). The odds of clinical chorioamnionitis were almost 3-fold higher among infant-mother dyads with histological fetal inflammatory response than among infant-mother dyads with histological chorioamnionitis alone (pooled odds ratio, 2.99; 95% confidence interval, 1.96-4.55).

CONCLUSION

This study investigated multiple neonatal outcomes and found association in the case of 4 major morbidities: early-onset sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, and retinopathy of prematurity.

Relationship between chorioamnionitis or funisitis and lung injury among preterm infants: meta-analysis involved 16 observational studies with 68,397 participants

BACKGROUND

Chorioamnionitis (CA) can cause multiple organ injuries in premature neonates, particularly to the lungs. Different opinions exist regarding the impact of intrauterine inflammation on neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD). We aim to systematically review the relationship between CA or Funisitis (FV) and lung injury among preterm infants.

METHODS

We electronically searched PubMed, EMbase, the Cochrane library, CNKI, and CMB for cohort studies from their inception to March 15, 2023. Two reviewers independently screened literature, gathered data, and did NOS scale of included studies. The meta-analysis was performed using RevMan 5.3.

RESULTS

Sixteen observational studies including 68,397 patients were collected. Meta-analysis showed CA or FV increased the lung injury risk (OR = 1.43, 95%CI: 1.06-1.92). Except for histological chorioamnionitis (HCA) (OR = 0.72, 95%CI: 0.57-0.90), neither clinical chorioamnionitis (CCA) (OR = 1.86, 95%CI: 0.93-3.72) nor FV (OR = 1.23, 95%CI: 0.48-3.15) nor HCA with FV (OR = 1.85, 95%CI: 0.15-22.63) had statistical significance in NRDS incidence. As a result of stratification by grade of HCA, HCA (II) has a significant association with decreased incidence of NRDS (OR = 0.48, 95%CI: 0.35-0.65). In terms of BPD, there is a positive correlation between BPD and CA/FV (CA: OR = 3.18, 95%CI: 1.68-6.03; FV: OR = 6.36, 95%CI: 2.45-16.52). Among CA, HCA was positively associated with BPD (OR = 2.70, 95%CI: 2.38-3.07), whereas CCA was not associated with BPD (OR = 2.77, 95%CI: 0.68-11.21). HCA and moderate to severe BPD (OR = 25.38, 95%CI: 7.13-90.32) showed a positive correlation, while mild BPD (OR = 2.29, 95%CI: 0.99-5.31) did not.

CONCLUSION

Currently, evidence suggests that CA or FV increases the lung injury incidence in premature infants. For different types of CA and FV, HCA can increase the incidence of BPD while decreasing the incidence of NRDS. And this "protective effect" only applies to infants under 32 weeks of age. Regarding lung injury severity, only moderate to severe cases of BPD were positively correlated with CA.

Prediction scores based on neonatal inflammatory markers for chorioamnionitis and funisitis in extremely low gestational age neonates

AIM

The aim of the study was to examine the predictive value of inflammatory markers for chorioamnionitis and funisitis in extremely low gestational age neonates.

METHODS

According to the Redline histopathological classification, extremely low gestational age neonates were classified into: (1) maternal inflammatory response ≤1 or ≥2, based on inflammatory findings of the placenta and (2) foetal inflammatory response ≤1 or ≥2, based on inflammatory findings of the umbilical cord. On admission and 12-36 h postnatally, procalcitonin and high-sensitivity C-reactive protein levels and white blood cell and neutrophil counts were compared. For both maternal and foetal inflammatory responses ≥2, the predictive value of each inflammatory marker was calculated.

RESULTS

On admission, procalcitonin had the best predictive value for maternal and foetal inflammatory response ≥2. The maternal inflammatory response ≥2 prediction score includes procalcitonin level on admission, high-sensitivity C-reactive protein level and white blood cell count at 12-36 h postnatally. Foetal inflammatory response ≥2 prediction score includes procalcitonin level and white blood cell count on admission and 12-36 h postnatally. The sensitivities were 96.4% and 96.3%, respectively.

CONCLUSION

Procalcitonin, high-sensitivity C-reactive protein levels and white blood cell count provide highly sensitive prediction scores for chorioamnionitis and funisitis in extremely low gestational age neonates.

Insights into the Black Box of Intra-Amniotic Infection and Its Impact on the Premature Lung: From Clinical and Preclinical Perspectives

Intra-amniotic infection (IAI) is one major driver for preterm birth and has been demonstrated by clinical studies to exert both beneficial and injurious effects on the premature lung, possibly due to heterogeneity in the microbial type, timing, and severity of IAI. Due to the inaccessibility of the intra-amniotic cavity during pregnancies, preclinical animal models investigating pulmonary consequences of IAI are indispensable to elucidate the pathogenesis of bronchopulmonary dysplasia (BPD). It is postulated that on one hand imbalanced inflammation, orchestrated by lung immune cells such as macrophages, may impact on airway epithelium, vascular endothelium, and interstitial mesenchyme, resulting in abnormal lung development. On the other hand, excessive suppression of inflammation may as well cause pulmonary injury and a certain degree of inflammation is beneficial. So far, effective strategies to prevent and treat BPD are scarce. Therapeutic options targeting single mediators in signaling cascades and mesenchymal stromal cells (MSCs)-based therapies with global regulatory capacities have demonstrated efficacy in preclinical animal models and warrant further validation in patient populations. Ante-, peri- and postnatal exposome analysis and therapeutic investigations using multiple omics will fundamentally dissect the black box of IAI and its effect on the premature lung, contributing to precisely tailored and individualized therapies.

[Association of different stages of histological chorioamnionitis with respiratory distress syndrome in preterm infants with a gestational age of < 32 weeks]

OBJECTIVE

To study the association of different stages of histological chorioamnionitis (HCA) with the incidence rate and severity of respiratory distress syndrome (RDS) in preterm infants.

METHODS

Related data were collected from the infants and their mothers who were treated in the Neonatal Intensive Care Unit of Qingdao Women and Children's Hospital, Qingdao University, from January 2018 to June 2020. According to the presence or absence of HCA and its stage, the infants were divided into four groups: control (n=109), early-stage HCA (n=126), middle-stage HCA (n=105), and late-stage HCA (n=36). The four groups were compared in terms of gestational age, birth weight, sex, maternal age, placental abruption, prenatal use of antibiotics, and incidence rate of RDS. The correlation between HCA stage and RDS severity was analyzed.

RESULTS

Compared with the control and late-stage HCA groups, the early-stage HCA group had a significantly lower incidence rate of placental abruption and a significantly higher rate of prenatal use of antibiotics (P < 0.05), and the early-stage HCA group had a significantly lower incidence rate of RDS than the control group (P < 0.05). The multivariate logistic regression analysis showed that early-, middle-, and late-stage HCA were protective factors against RDS (P < 0.05). The Spearman test showed that the severity of RDS in preterm infants was not correlated with the HCA stage (P > 0.05).

CONCLUSIONS

Early-, middle-, and late-stage HCA can reduce the incidence rate of RDS in preterm infants. HCA stage may not be correlated with RDS severity in preterm infants, which needs to be verified by further research.

The effect of concomitant histologic chorioamnionitis in pregnancies complicated by fetal growth restriction

INTRODUCTION

We aimed to investigate the effect of placental histologic chorioamnionitis (HC) on neonatal outcomes in pregnancies complicated by fetal growth restriction (FGR).

METHODS

- The computerized medical files of all pregnancies diagnosed with FGR (birthweight <10th percentile) at 24-42 weeks of gestation between 2008 and 2019 were reviewed. Maternal and neonatal outcomes were compared between FGR with and without evidence of placental HC. Placental lesions were classified according to "Amsterdam" criteria. Composite adverse neonatal outcome-included any of the following complications: neurological morbidity, neonatal respiratory assistance, RDS, NEC, sepsis, blood transfusion, phototherapy, hypoglycemia, or neonatal death. Composite severe adverse neonatal outcome included any of the following complications - neurological morbidity, blood transfusion, NEC, sepsis, RDS, neonatal death.

RESULTS

- Compared to FGR without HC (n = 446), FGR with HC (n = 57) was characterized by more advanced gestational age at delivery 39.2 (38.3-39.9) vs. 38.2 (36.9-39.2), weeks respectively, p < 0.001), higher rate of nulliparity (73.7% vs. 45.1%, p < 0.001), less vascular lesions of MVM (1.8% vs.11.2%, p = 0.02), higher rate of Apgar scores at 5 min <7 (10.5% vs. 2%, p = 0.004), increased neonatal death (7.0% vs. 0.9%, p = 0.007), higher rates of both composite adverse neonatal outcome (31.1% vs. 17.3% p = 0.02), and composite severe adverse neonatal outcome (16.3% vs. 8.2% p = 0.04). By multivariate regression analysis HC was found to be independently associated with composite adverse neonatal outcome (aOR = 1.21, 95% CI 1.08-2.38) and with severe composite adverse neonatal outcome (aOR = 1.39, 95% CI 1.16-3.76).

CONCLUSIONS

Pregnancies complicated by FGR with concomitant HC were associated with higher rates of adverse neonatal outcomes.

FGR in the setting of preterm sterile intra-uterine milieu is associated with a decrease in RDS

OBJECTIVE

To determine if fetal growth restriction (FGR) in the setting of sterile intra-uterine milieu would be associated with a decrease in respiratory distress syndrome (RDS) of preterm-neonates.

METHODS

The relationship between FGR and neonatal RDS was examined in 92 singleton preterm-neonates (gestational age [GA]: 24.5-33.4 weeks) born to mothers with sterile intra-uterine milieu, which consisted of both sterile amniotic fluid (AF), and inflammation-free placenta. Sterile AF was defined in the absence of both infection and inflammation in AF. AF inflammation was defined in the presence of AF MMP-8 ≥23 ng/ml. FGR was defined in the presence of birth-weight (BW) below the 5th percentile for GA.

RESULTS

FGR was present in 32% and RDS was found in 46% of patients. RDS was less common (24% vs. 56%; P < 0.01) and umbilical arterial pH at birth ≤7.15 was more common (33% vs. 13%; P < 0.05) in preterm-neonates with FGR than in those without FGR. There is a stepwise increase in RDS with increasing BW (i.e., below the 5th percentile, the 5th ∼10th percentile, and above the 10th percentile for GA) (P < 0.01, linear by linear association). Logistic regression analysis demonstrated that FGR was a better independent predictor of a decrease in RDS (OR = 0.049, 95%CI 0.009-0.259, P < 0.0005) than advanced GA at delivery (OR = 0.584, 95%CI 0.423-0.806, P < 0.005) after adjusting for other confounding variables.

CONCLUSION

FGR in the setting of sterile intra-uterine milieu is associated with a decrease in RDS of preterm-neonates. This observation suggests that chronic intra-uterine hypoxic stress related to FGR may be beneficial to fetal lung maturation. Pediatr Pulmonol. 2016;51:812-819. © 2015 Wiley Periodicals, Inc.

Gastric fluid versus amniotic fluid analysis for the identification of intra-amniotic infection due to Ureaplasma species

OBJECTIVE

Early neonatal sepsis is often due to intra-amniotic infection. The stomach of the neonate contains fluid swallowed before and during delivery. The presence of bacteria as well as neutrophils detected by culture or Gram stain of the gastric fluid during the first day of life is suggestive of exposure to bacteria or inflammation. We undertook this study to determine the relationship between gastric fluid analysis and amniotic fluid obtained by transabdominal amniocentesis in the detection of Ureaplasma species, the most frequent microorganisms responsible for intra-amniotic infection.

MATERIALS AND METHODS

The study population consisted of 100 singleton pregnant women who delivered preterm neonates (<35 weeks) within 7 days of amniocentesis. Gastric fluid of newborns was obtained by nasogastric intubation on the day of birth. Amniotic fluid and gastric fluid were cultured for genital Mycoplasmas, and polymerase chain reaction (PCR) for Ureaplasma species was performed. Intra-amniotic inflammation was defined as an elevated amniotic fluid matrix metalloproteinase-8 concentration (>23 ng/mL).

RESULTS

(1) Ureaplasma species were detected by culture or PCR in 18% (18/100) of amniotic fluid samples and in 5% (5/100) of gastric fluid samples; (2) among the amniotic fluid cases positive for Ureaplasma species, these microorganisms were identified in 27.8% (5/18) of gastric fluid samples; (3) none of the cases negative for Ureaplasma species in the amniotic fluid were found to be positive for these microorganisms in the gastric fluid; (4) patients with amniotic fluid positive for Ureaplasma species but with gastric fluid negative for these microorganisms had a significantly higher rate of intra-amniotic inflammation, acute histologic chorioamnionitis, and neonatal death than those with both amniotic fluid and gastric fluid negative for Ureaplasma species; and (5) no significant differences were observed in the rate of intra-amniotic inflammation, acute histologic chorioamnionitis, and neonatal death between patients with amniotic fluid positive for Ureaplasma species but with gastric fluid negative for these microorganisms and those with both amniotic fluid and gastric fluid positive for Ureaplasma species.

CONCLUSIONS

Gastric fluid analysis has 100% specificity in the identification of intra-amniotic infection with Ureaplasma species. However, the detection of Ureaplasma species by culture or PCR in the gastric fluid of neonates at birth did not identify these microorganisms in two-thirds of cases with microbial invasion of the amniotic cavity. Thus, amniotic fluid analysis is superior to that of gastric fluid in the identification of intra-amniotic infection.

The inflammatory milieu of amniotic fluid in acute-chorioamnionitis decreases with increasing gestational age

INTRODUCTION

The inflammatory milieu decreases in the placenta and amniotic fluid (AF) with gestational age (GA). However, there is no information about whether the inflammatory milieu of AF in the setting of the same placental inflammatory condition decreases with GA. We hypothesized that the inflammatory milieu of AF in acute chorioamnionitis would decrease with increasing GA.

METHODS

The inflammatory milieu of AF was examined in 617 singleton preterm pregnancies (<36 weeks) delivered within 5 days of amniocentesis. Study population was divided into GA at delivery ≤30 weeks (n = 148), 30-34 weeks (n = 226), and 34-36 weeks (n = 226). Acute-chorioamnionitis was classified according to the severity (i.e., mild, total grade 1; moderate, total grade 2; and severe, total grade 3-6) or involved compartment (i.e., chorionic plate, amnion and chorio-decidua). The inflammatory milieu of AF was determined by matrix metalloproteinase-8 (MMP-8) concentration.

RESULTS

1) AF MMP-8 concentrations decreased in patients with acute-chorioamnionitis (P < 0.001), but not inflammation-free placenta, with increasing GA; 2) AF MMP-8 concentrations were less intense at higher GA in patients with moderate and severe (each-for P < 0.005), but not mild, acute-chorioamnionitis; 3) AF MMP-8 concentrations decreased in the context of the same involved compartment (i.e., chorionic plate inflammation, amnionitis, or chorio-deciduitis) of acute-chorioamnionitis (each-for P < 0.001) with increasing GA; 4) Moreover, there was a significant inverse relationship between GA and AF MMP-8 concentrations in patients with acute-chorioamnionitis (r = -0.453, P < 0.0000001), but not inflammation-free placenta (r = -0.071, P = 0.170).

DISCUSSION

AF MMP-8 concentrations in acute-chorioamnionitis distinctly decrease throughout preterm-gestation. This finding suggests that the inflammatory milieu of AF decrease in acute-chorioamnionitis with GA.