Preterm prelabour amniorrhexis: relation to histological chorioamnionitis

Inflammatory Signalling in Fetal Membranes: Increased Expression Levels of TLR 1 in the Presence of Preterm Histological Chorioamnionitis

Histological chorioamnionitis (HCA) is an established marker of ascending infection, a major cause of preterm birth. No studies have characterised the global change in expression of genes involved in the toll-like receptor (TLR) signalling pathways in the presence of HCA in the setting of preterm birth (pHCA). Fetal membranes were collected immediately after delivery and underwent histological staging for inflammation to derive 3 groups; term spontaneous labour without HCA (n = 9), preterm birth <34 weeks gestation without HCA (n = 8) and pHCA <34 weeks (n = 12). Profiling arrays ran in triplicate for each group were used to determine the expression of 84 genes associated with TLR signalling and screen for genes of interest (fold change >2; p<0.1). Expression of identified genes was validated individually for all samples, relative to GAPDH, using RT-PCR. Expression of TLR 1, TLR 2, lymphocyte antigen 96, interleukin 8 and Interleukin-1 receptor-associated kinase-like 2 was increased in pHCA (p<0.05). Degree of expression was positively associated with histological staging of both maternal and fetal inflammation (p<0.05). The inflammatory expression profile at the maternal/fetal interface associated with pHCA, a reflection of ascending infection, is extremely heterogeneous suggesting polymicrobial involvement with activation of a common pathway. Antagonism of TLR 1 and TLR 2 signalling in this setting warrants further assessment.

Frozen section of placental membranes and umbilical cord: an aid to early postpartum diagnosis of intra-amniotic infection

OBJECTIVES

We devised a rapid frozen section (FS) assessment technique of placental tissues and performed the first rigorous assessment of FS relative to conventional workup.

METHODS

We evaluated 49 placentas with clinical/gross suspicion of intra-amniotic infection by FS. Relative to formalin-fixed and paraffin-embedded tissues, we compared the grading, staging, and interobserver variability.

RESULTS

FS assessment demonstrated a sensitivity of 0.91 (95% CI, 0.77-0.97) and a specificity of 0.60 (95% CI, 0.36-0.80) for the presence of chorioamnionitis and a sensitivity of 0.89 (95% CI, 0.75-0.96) and a specificity of 0.69 (95% CI, 0.42-0.87) for the presence of funisitis. The χ2 goodness of fit for grade and stage in both placental membrane and umbilical cord sections was significant (P<.001). There was no significant difference in interobserver variability in comparison with permanent section results (P=0.06).

CONCLUSIONS

We conclude that FS is a reasonably sensitive screening technique, correlating well with conventional assessment, without significantly different interobserver variability.

Use of C-reactive protein as a predictor of chorioamnionitis in preterm prelabour rupture of membranes: a systematic review

BACKGROUND

Studies examining the use of C-reactive protein (CRP) as a predictor of chorioamnionitis in preterm prelabour rupture of membranes (PPROM) report highly conflicting results. Despite this, CRP is commonly used for the early diagnosis of chorioamnionitis.

OBJECTIVE

To determine the diagnostic accuracy of CRP in the detection of chorioamnionitis in women with PPROM.

DESIGN

Systematic review.

SEARCH STRATEGY

Studies were identified from MEDLINE (1966-2006), EMBASE (1974-2006), PubMed and the Cochrane Library (2005) and from reference lists from primary studies and reviews.

SELECTION CRITERIA

Only studies of good methodological quality that evaluated the diagnostic performance of CRP in chorioamnionitis in women with PPROM were selected.

DATA COLLECTION AND ANALYSIS

Positive and negative likelihood ratios (LR) and diagnostic odds ratios (DOR) were calculated. An attempt was made at pooling data for meta-analysis, but this was considered inappropriate due to the significant unexplained heterogeneity between studies.

MAIN RESULTS

There were eight primary studies comprising 610 cases which met the inclusion criteria. There was wide variation in the positive and negative LR and DOR between the studies, with significant lack of precision demonstrated by wide confidence intervals. Three of the studies concluded that CRP was a useful diagnostic tool for chorioamnionitis (DOR ranging from 4.2 to 191.6), although one of them suggested a higher CRP threshold. The other five studies concluded the opposite (DOR ranging from 1.4 to 17.7).

AUTHOR'S CONCLUSIONS

There is no clear evidence to support the use of CRP for the early diagnosis of chorioamnionitis. Further research is required to address the contradictory findings of diagnostic accuracy.

Chorioamnionitis risk and neonatal outcome in preterm premature rupture of membranes

OBJECTIVE

The objective of this study was to compare the neonatal outcome in patients with preterm premature rupture of membranes with and without clinical chorioamnionitis.

STUDY DESIGN

This is a retrospective study that included 254 pregnant women with preterm rupture of membranes. The study group was divided according to the presence or absence of clinical chorioamnionitis defined as the presence of two or more of the following criteria: maternal temperature >38 degrees C on two or more occasions > or =1 h apart, maternal tachycardia (> or =120 beats/min), uterine tenderness, foul smelling amniotic fluid, maternal leukocytosis > or =20,000 mm(-3) with bands and positive C reactive protein. Also the study population was divided according to the use of tocolysis. Exclusion criteria included multiple pregnancy, fetal congenital anomalies, diabetes mellitus and severe preeclampsia. Amniotic fluid was collected from the cervix or from the transabdominal amniocentesis. Antibiotics and tocolysis were used according to the hospital protocols. Parametric and nonparametric statistics were used for comparisons.

RESULTS

There were no significant differences in birth weight, Apgar scores at 1 and 5 min, rates of respiratory distress syndrome, intraventricular hemorrhage and necrotizing enterocolitis between patients with and without clinical chorioamnionitis or between women who received tocolysis and the ones that did not receive tocolysis. In cases of clinical chorioamnionitis and when tocolysis was used the neonates stayed longer in the neonatal intensive care unit (NICU).

CONCLUSION

Patients with preterm premature rupture of membranes and clinical chorioamnionitis have similar neonatal outcomes than the ones without clinical chorioamnionitis.

Role of amniocentesis for the diagnosis of subclinical intra-amniotic infection in preterm premature rupture of the membranes

The clinical role of amniocentesis in the management of pregnancies that are complicated by preterm premature rupture of the membranes remains unclear. The indiscriminant use of expectant management, corticosteroids, and empiric antibiotic therapy without knowledge of the presence or absence of intra-amniotic infection poses underappreciated risks to the fetus. This clinical opinion presents the argument that amniocentesis should be an integral part of the management of patients with preterm premature rupture of the membranes. The technical aspects of amniocentesis, the associations between subclinical infection and neonatal morbidity, and the limitations of current interventions are reviewed, and suggestions for future studies that are sorely needed are offered.