The role of the maternal and fetal inflammatory response in retinopathy of prematurity

PROBLEM

There is a paucity of research on the contribution of placental inflammation to severe retinopathy of prematurity (ROP).

METHOD OF STUDY

A retrospective cohort study (n = 1217) was conducted of infants screened for ROP (2006-2016). The outcomes of the study were severe ROP (type 1 or type 2 ROP) and low grade ROP. We categorized the placental pathology as the presence of (i) maternal plus fetal inflammatory response, (ii) maternal inflammatory response only, (iii) fetal inflammatory response only and, (iv) no evidence of a maternal or fetal inflammatory response. The data were analyzed using univariate and multivariate logistic regression analyses (P < .05).

RESULTS

In this cohort, the number of infants with the maternal plus fetal inflammatory response, the maternal inflammatory response only, the fetal inflammatory response only, and no maternal or fetal inflammatory response was 305 (25%), 82 (7%), 8 (1%), and 822 (67%), respectively. Adjusted for covariates, the maternal plus fetal inflammatory response was a significant risk factor for severe ROP (AOR = 2.6, 95% CI 1.1-5.9, P = .03). None of the categories of placental inflammation were significantly associated with low grade ROP.

CONCLUSION

Placental pathology distinguished by the maternal plus fetal inflammatory response was a significant risk factor for severe ROP. Our study supports a link between intrauterine inflammatory events and the subsequent development of severe ROP.

Placenta in intrauterine fetal demise (IUFD): a comprehensive study from a tertiary care hospital

Background: Intrauterine fetal demise (IUFD) is an unpredictable and challenging obstetric complication. Its etiology is multifactorial with more than 60% attributed to the placental cause. The present study was done with a primary objective of understanding the placental lesions underlying IUFD. Methods: In this retrospective observational study, IUFD cases (>22 weeks) between January 2012 and September 2015 were collected from pathology database. The clinical details with ultrasound findings were collected from mother's charts. The lesions were classified into (A) maternal vascular malperfusion (MVM) including retroplacental hematomas, (B) fetal vascular malperfusion (FVM), (C) inflammatory lesions, and (D) idiopathic. The contributor to fetal death was classified as direct, major, minor, unlikely, or unknown. Placental findings of fetal hypoxia were recorded. Results: The study included 100 cases of IUFD. The mean maternal age was 26 years (18-36 years). Primipara were 46. There were 65 early preterm (PT) (<34 weeks), 20 late PT (34 weeks to <37 weeks) and 15 term (>37 weeks) IUFD. The mean gestation age was 30 weeks. The ratio of male:female fetuses was 1:1.7. Relevant obstetric complications included preeclampsia (n = 39), intrauterine growth restriction (IUGR) (n = 7), pre-gestational diabetes (n = 7), bad obstetric history (n = 6), oligohydramnios (n = 5). The mean placental weight was 256 g. Maternal vascular malperfusion had the highest incidence (30%), followed by combined maternal and FVM (10%). Exclusive inflammatory lesions and FVM were seen in 12 and 6%, respectively. No cause was identified in 18%. Direct contributor to IUFD was identified in 51 cases and major, minor, unlikely contribution in 21, 11 and nine cases, respectively. In nine cases, it was unknown. Lesions indicating fetal hypoxia were noted in 35 cases. In both early and late PT, MVM featured more commonly (23 and 5%). In term placentas, the most common cause was idiopathic. Conclusions: Lesions of MVM were the most common cause of IUFD and served as a direct contributor to fetal demise.

Funisitis increases the risk of death or cerebral palsy in extremely preterm infants

BACKGROUND

The relationship between histological chorioamnionitis (inflammation of fetal membranes) and funisitis (inflammation of umbilical cord), both commonly associated with preterm birth, with subsequent development of cerebral palsy remains controversial.

OBJECTIVE

To determine if extremely preterm infants (<27 weeks) exposed to histological chorioamnionitis or funisitis are at a higher risk of death or cerebral palsy compared to those without these exposures.

STUDY DESIGN

Multicenter cohort study of prospectively collected data of preterm infants in the National Institute of Child Health and Development Neonatal Research Network. Infants born 2012 to 2019 who were 22 to 266/7 weeks of gestation, received active treatment, and had placental pathology available were included. Because preterm birth, as measured by gestational age, lies on the causal pathway for cerebral palsy, we used mediation analysis to evaluate whether the indirect mediated effect of gestational age on death or cerebral palsy contributed to the relationships of histological chorioamnionitis and funisitis with death or cerebral palsy.

MAIN OUTCOMES AND MEASURES

The primary outcome was the composite outcome of death or cerebral palsy defined by the Amiel-Tison standardized exam and Gross Motor Function Classification System ≥1 at 22 to 26 months corrected age.

RESULTS

A total of 6949 infants met the eligibility criteria. Of these, 3971 (57%) infants had histological chorioamnionitis, and 2978 (43%) did not have histological chorioamnionitis. About 90% (6248/6949) of infants had follow-up and complete cerebral palsy data. Similarly, 1057 (28%) infants had funisitis, and 2689 (72%) did not have funisitis. Of these, primary outcome data were available for 87% (3267/3746) infants. On multivariable analysis, histological chorioamnionitis was not associated with death or cerebral palsy (relative risk: 0.98 [95% confidence interval: 0.91, 1.05]). Exposure to funisitis was associated with a higher risk of death or cerebral palsy (relative risk: 1.09 [1.01, 1.21]) that was primarily mediated by preterm birth. There was a higher risk of cerebral palsy among surviving infants exposed to funisitis (relative risk: 1.23 [1.04, 1.51]) compared to those without funisitis. This association was partially (40%) mediated by preterm birth (relative risk: 1.08 [1.05, 1.12]), but the major effect (60%) appears to be a direct adverse effect of funisitis exposure on cerebral palsy development (relative risk: 1.13 [0.97, 1.40]).

CONCLUSION

Funisitis was associated with an increased risk of the combined outcome of death or cerebral palsy. In surviving infants, the direct adverse effects of funisitis appear to lead to cerebral palsy, independent of preterm birth.

The value of umbilical cord insertion site sampling in detecting maternal and/or fetal inflammatory response

The 2016 Amsterdam Placental Workshop Group Consensus Statement recommends sampling a block of the placenta close to the umbilical cord insertion site (UCIB) for histopathological evaluation. This piece of placenta at the umbilical cord insertion is presumed to give a better yield of inflammation (if present). We aimed to investigate the utility of the UCIB in the detection of maternal and/or fetal inflammatory responses (MIR and/or FIR), in comparison with the other sections of the placental parenchyma. This is a retrospective cross-sectional study including all placentas with histologic chorioamnionitis. The histopathological slides of placentas were reviewed as per Amsterdam consensus guidelines. Diagnostic performance of UCIB in identifying MIR and/or FIR, relative to the other placental sections, was assessed. UCIB revealed diagnostic sensitivity, specificity, and diagnostic accuracy of 79.2% (95% CI: 74.2-83.6%), 100.0% (95% CI: 95.6-100.0%), and 83.6% (95% CI: 79.5-87.2%), respectively, in the detection of FIR, while showing a low sensitivity of 52.6% (95% CI: 47.5-57.6%) in detecting MIR. In 59 (24.6%) cases, FIR was not seen in the corresponding placental parenchymal sections but was detected in the UCIBs. This study is the first study to confirm that a section from the UCIB is essential for the detection of FIR, which affirms the Amsterdam consensus sampling recommendations.

Quantitative Modeling to Characterize Maternal Inflammatory Response of Histologic Chorioamnionitis in Placental Membranes

PROBLEM

The placental membranes are a key barrier to fetal and uterine infection. Inflammation of the membranes, diagnosed as maternal inflammatory response (MIR) or alternatively as acute chorioamnionitis, is associated with adverse maternal-fetal outcomes. MIR is staged 1-3, with higher stages indicating more hazardous inflammation. However, the diagnosis relies upon subjective evaluation and has not been deeply characterized. The goal of this work is to develop a cell classifier for eight placental membrane cells and quantitatively characterize MIR1-2.

METHOD OF STUDY

Hematoxylin and eosin (H&E)-stained placental membrane slides were digitized. A convolutional neural network was trained on a dataset of hand-annotated and machine learning-identified cells. Overall cell class-level metrics were calculated. The model was applied to 20 control, 20 MIR1, and 23 MIR2 placental membrane cases. MIR cell composition and neutrophil distribution were assessed via density and Ripley's cross K-function. Clinical data were compared to neutrophil density and distribution.

RESULTS

The classification model achieved a test-set accuracy of 0.845, with high precision and recall for amniocytes, decidual cells, endothelial cells, and trophoblasts. Using this model to classify 53 073 cells from healthy and MIR1-2 placental membranes, we found that (1) MIR1-2 have higher neutrophil density and fewer decidual cells and trophoblasts, (2) Neutrophils colocalize heavily around decidual cells in healthy placental membranes and around trophoblasts in MIR1, (3) Neutrophil density impacts distribution in MIR, and (4) Neutrophil metrics correlate with features of clinical chorioamnionitis.

CONCLUSIONS

This paper introduces cell classification into the placental membranes and quantifies cell composition and neutrophil spatial distributions in MIR.