Assessment of fetal activity and amniotic fluid volume in the prediction of intrauterine infection in preterm prelabor amniorrhexis

[Current approach in preterm prelabor rupture of membranes: new definitions? Is CRP determination useful? Are alternatives in sight?]

Around 3% of all pregnancies are complicated by preterm prelabor rupture of membranes (PPROM) before 37 + 0 weeks of gestation. Since PPROM is likely to be associated with microbial invasion of the amniotic cavity (MIAC)-either before or secondary to PPROM-the risk of developing intraamniotic inflammation (IAI) is high. IAI is associated with short latency to delivery and with adverse short- and long-term outcomes for the newborn, especially in cases of fetal inflammatory response syndrome (FIRS). Prediction of IAI based on maternal parameters is difficult or impossible. The recently established definition of triple I ("infection, inflammation, or both") is based on the parameter "maternal body temperature". If this is increased to ≥ 38.0 °C and there is no other reason to explain maternal fever, the finding is suspicious for triple I if at least one other of the following parameters can be found: fetal tachycardia > 160 bpm for at least 10 min, maternal leukocytes > 15,000/µl without administration of corticosteroids, or purulent fluid from the cervical os. Pregnancies suspicious for triple I should be terminated. The confirmation of triple I is only possible by placental histology (histologically confirmed chorioamnionitis, HCA). Confirmation based on amniocentesis (positive Gram stain, low glucose concentration [<14 mg/dl], elevated white blood cell count [>30 cells/mm³], positive culture) takes too long and is unreliable. Serial determinations of C‑reactive protein also do not allow reliable diagnosis of IAI. Studies using interleukin 6 measurements from the posterior fornix and/or cervical os are promising methods, the validation of which is awaited.

The fetal inflammatory response syndrome: the origins of a concept, pathophysiology, diagnosis, and obstetrical implications

The fetus can deploy a local or systemic inflammatory response when exposed to microorganisms or, alternatively, to non-infection-related stimuli (e.g., danger signals or alarmins). The term "Fetal Inflammatory Response Syndrome" (FIRS) was coined to describe a condition characterized by evidence of a systemic inflammatory response, frequently a result of the activation of the innate limb of the immune response. FIRS can be diagnosed by an increased concentration of umbilical cord plasma or serum acute phase reactants such as C-reactive protein or cytokines (e.g., interleukin-6). Pathologic evidence of a systemic fetal inflammatory response indicates the presence of funisitis or chorionic vasculitis. FIRS was first described in patients at risk for intraamniotic infection who presented preterm labor with intact membranes or preterm prelabor rupture of the membranes. However, FIRS can also be observed in patients with sterile intra-amniotic inflammation, alloimmunization (e.g., Rh disease), and active autoimmune disorders. Neonates born with FIRS have a higher rate of complications, such as early-onset neonatal sepsis, intraventricular hemorrhage, periventricular leukomalacia, and death, than those born without FIRS. Survivors are at risk for long-term sequelae that may include bronchopulmonary dysplasia, neurodevelopmental disorders, such as cerebral palsy, retinopathy of prematurity, and sensorineuronal hearing loss. Experimental FIRS can be induced by intra-amniotic administration of bacteria, microbial products (such as endotoxin), or inflammatory cytokines (such as interleukin-1), and animal models have provided important insights about the mechanisms responsible for multiple organ involvement and dysfunction. A systemic fetal inflammatory response is thought to be adaptive, but, on occasion, may become dysregulated whereby a fetal cytokine storm ensues and can lead to multiple organ dysfunction and even fetal death if delivery does not occur ("rescued by birth"). Thus, the onset of preterm labor in this context can be considered to have survival value. The evidence so far suggests that FIRS may compound the effects of immaturity and neonatal inflammation, thus increasing the risk of neonatal complications and long-term morbidity. Modulation of a dysregulated fetal inflammatory response by the administration of antimicrobial agents, anti-inflammatory agents, or cell-based therapy holds promise to reduce infant morbidity and mortality.

Utility of ultrasound assessment in management of pregnancies with preterm prelabor rupture of membranes

OBJECTIVES

To evaluate the utility of ultrasound markers in the management of pregnancies complicated by preterm prelabor rupture of membranes (PPROM) between 23 + 0 and 33 + 6 weeks' gestation, and to assess the ability of ultrasound markers to predict adverse neonatal outcomes.

METHODS

This was a retrospective cohort study of all patients with PPROM between 23 + 0 and 33 + 6 weeks' gestation and latency period (PPROM to delivery) > 48 h, who delivered before 34 weeks' gestation at a tertiary referral center between 2005 and 2017. All patients underwent a non-stress test daily and an ultrasound scan twice a week for assessment of amniotic fluid volume, biophysical profile (BPP) and umbilical artery (UA) pulsatility index (PI). In patients with suspected fetal growth restriction, fetal middle cerebral artery (MCA)-PI was also assessed and the cerebroplacental ratio (CPR) calculated. The last ultrasound examination performed prior to delivery was analyzed. We compared the characteristics and outcomes between women who were delivered owing to clinical suspicion of chorioamnionitis and those who were not delivered for this indication. The primary objective was to evaluate the utility of ultrasound in the management of patients with PPROM. The secondary objective was to assess the diagnostic performance of ultrasound markers (BPP score < 6, oligohydramnios, UA-PI > 95^th percentile, MCA-PI < 5^th percentile, CPR < 5^th percentile) for the prediction of composite adverse neonatal outcome, which was defined as the presence of one or more of: perinatal death, respiratory distress syndrome, periventricular leukomalacia, intraventricular hemorrhage Grade 3 or 4, necrotizing enterocolitis, hypoxic ischemic encephalopathy, neonatal sepsis or neonatal seizures.

RESULTS

A total of 504 women were included in the study, comprising 120 with suspected chorioamnionitis and 384 without. Women with suspected chorioamnionitis, compared with those without, were less likely to be nulliparous (34.2% vs 45.3%; P = 0.03) and more likely to have fever (50.8% vs 2.6%; P < 0.001) and be delivered by Cesarean section (69.2% vs 42.4%; P < 0.001), mainly owing to a history of previous Cesarean section (18.3% vs 9.1%; P = 0.005) and to having non-reassuring fetal heart rate tracings (32.5% vs 14.6%; P < 0.001). No significant differences were found between the two groups with regard to the median amniotic fluid volume, overall BPP score, BPP score < 6, MCA-PI or CPR. Median UA-PI was slightly higher in the suspected-chorioamnionitis group, yet the incidence of UA-PI > 95^th percentile was similar between the two groups. There was a higher incidence of composite adverse neonatal outcome in the group with suspected chorioamnionitis than in the group without (78.3% vs 64.3%, respectively; P = 0.004). However, on logistic regression analysis, none of the ultrasound markers evaluated was found to be associated with chorioamnionitis or composite adverse neonatal outcome, and they all had a poor diagnostic performance for the prediction of chorioamnionitis and composite adverse neonatal outcome.

CONCLUSIONS

Commonly used ultrasound markers in pregnancies complicated by PPROM were similar between women delivered for suspected chorioamnionitis and those delivered for other indications, and performed poorly in predicting composite adverse neonatal outcome. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Amniotic fluid volume at presentation with early preterm prelabor rupture of membranes and association with severe neonatal respiratory morbidity

OBJECTIVE

Amniotic fluid volume (AFV) plays an important role in early fetal lung development, and oligohydramnios in early pregnancy is associated with pulmonary hypoplasia. The aim of this study was to evaluate the association between AFV at the time of presentation with early preterm prelabor rupture of membranes (PPROM) and severe neonatal respiratory morbidity and other adverse pregnancy outcomes.

METHODS

This was a retrospective study of all women with a singleton pregnancy, admitted to a single tertiary referral center between 2004 and 2014, for expectant management of PPROM at 20 + 0 to 28 + 6 weeks' gestation. The primary exposure was AFV at presentation, classified according to sonographic maximum vertical pocket (MVP) as: normal AFV (> 2 cm), oligohydramnios (≤ 2 cm and > 1 cm) or severe oligohydramnios (≤ 1 cm). The primary outcome was a composite variable of severe respiratory morbidity, defined as either of the following: (1) need for respiratory support in the form of mechanical ventilation using an endotracheal tube for ≥ 72 h and need for surfactant; or (2) bronchopulmonary dysplasia, defined as requirement for oxygen at postmenstrual age of 36 weeks or at the time of transfer to a Level-II facility. Adjusted odds ratios (aOR) and 95% CI for the primary and secondary outcomes were calculated for each AFV-at-presentation group (using normal AFV as the reference), adjusting for gestational age (GA) at PPROM, latency period, birth weight, mode of delivery and chorioamnionitis.

RESULTS

In total, 580 women were included, of whom 304 (52.4%) had normal AFV, 161 (27.8%) had oligohydramnios and 115 (19.8%) had severe oligohydramnios at presentation. The rates of severe respiratory morbidity were 16.1%, 26.7% and 45.2%, respectively. Compared with normal AFV at presentation, oligohydramnios (aOR, 3.27; 95% CI, 1.84-5.84) and severe oligohydramnios (aOR, 4.11; 95% CI, 2.26-7.56) at presentation were associated independently with severe respiratory morbidity. Other variables that were associated independently with the primary outcome were GA at PPROM (aOR, 0.54; 95% CI, 0.43-0.69), latency period (aOR, 0.94; 95% CI, 0.91-0.98) and Cesarean delivery (aOR, 2.01; 95% CI, 1.21-3.32).

CONCLUSIONS

In women with early PPROM, AFV at presentation, as assessed by the MVP on ultrasound examination, is associated independently with severe neonatal respiratory morbidity. This information may be taken into consideration when counseling women with early PPROM regarding neonatal outcome and management options. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Preterm Premature Rupture of Membranes: A Review of 3 National Guidelines

Importance

Preterm premature rupture of membranes (PPROM) is a major cause of perinatal mortality and morbidity.

Objective

The aim of this study was to compare recommendations from published national guidelines for pregnancies complicated with PPROM.

Evidence Acquisition

A descriptive review of 3 national guidelines on PPROM was performed: the Royal College of Obstetricians and Gynaecologists on "Preterm Prelabour Rupture of Membranes," the American College of Obstetricians and Gynecologists on "Premature Rupture of Membranes," and the Society of Obstetricians and Gynaecologists of Canada on "Antibiotic Therapy in Preterm Premature Rupture of the Membranes." Guidelines were compared in the diagnosis and management of PPROM. Recommendations and strength of evidence were reviewed based on each guideline's method of reporting. The references were compared with regard to their total number, total number of randomized controlled trials, Cochrane reviews, and systematic reviews/meta-analyses cited.

Results

The variations stated on the guidelines reflect the heterogeneity of the literature contributing to the guidelines and challenges of diagnosing and managing cases of PPROM.

Conclusions

An improved international guideline may improve safety and outcomes in pregnant women with PPROM.

[Diagnosis of rupture of fetal membranes: CNGOF Preterm Premature Rupture of Membranes Guidelines]

OBJECTIVE

To describe clinical and paraclinical tests diagnosing rupture of fetal membranes (ROM).

METHODS

Bibliographic search over the period 1980-2017 considering articles in French and English as well as guidelines from national obstetrical societies.

RESULTS

Typical amniotic fluid leakage occurs in ¾ of cases. In this situation, no additional test is required (Professional consensus). For ambiguous cases, a speculum examination can demonstrate pooling of amniotic fluid but suspicion can persist in 50% of cases (evidence level IV). In this context, we recommend to consider performing an IGFBP-1 or PAMG-1 test of vaginal fluid (evidence level III). Ability of these tests to reduce maternal or neonatal morbidity has never been demonstrated (Professional consensus). An isolated positive test should be considered cautiously as false positive does exist (Professional consensus).

CONCLUSION

Symptoms suggestive of ROM and speculum examination demonstrating pooling of amniotic fluid are sufficient to diagnose ROM. If pooling is not observed, we recommend to consider performing an IGFBP-1 or PAMG-1 test of vaginal fluid.

Fetal assessment methods for improving neonatal and maternal outcomes in preterm prelabour rupture of membranes

BACKGROUND

Fetal assessment following preterm prelabour rupture of membranes (PPROM) may result in earlier delivery due to earlier detection of fetal compromise. However, early delivery may not always be in the fetal or maternal interest, and the effectiveness of different fetal assessment methods in improving neonatal and maternal outcomes is uncertain.

OBJECTIVES

To study the effectiveness of fetal assessment methods for improving neonatal and maternal outcomes in PPROM. Examples of fetal assessment methods that would be eligible for inclusion in this review include fetal cardiotocography, fetal movement counting and Doppler ultrasound.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing any fetal assessment methods, or comparing one fetal assessment method to no assessment.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion into the review. The same two review authors independently assessed trial quality and independently extracted data. Data were checked for accuracy.

MAIN RESULTS

We included three studies involving 275 women (data reported for 271) with PPROM at up to 34 weeks' gestation. All three studies were conducted in the United States. Each study investigated different methods of fetal assessment. One study compared weekly endovaginal ultrasound scans with no assessment (n = 93), one compared amniocentesis with no assessment (n = 47), and one compared daily nonstress testing with daily modified biophysical profiling (n = 135). We were unable to perform a meta-analysis, but were able to report data from individual studies.There was no convincing evidence of increased risk of neonatal death in the group receiving endovaginal ultrasound scans compared with the group receiving no assessment (risk ratio (RR) 7.30, 95% confidence interval (CI) 0.39 to 137.54; one study, 92 women), or in the group receiving amniocentesis compared with the group receiving no amniocentesis (RR 1.00, 95% CI 0.07 to 15.00; one study, 44 women). For both these interventions, we inferred that there were no fetal deaths in the intervention or control groups. The study comparing daily nonstress testing with daily modified biophysical profiling did not report fetal or neonatal death. Primary outcomes of maternal death and serious maternal morbidity were not reported in any study. Overall, there were few statistically significant differences in outcomes between the comparisons.The overall quality of evidence is poor, because participant blinding was not possible for any study.

AUTHORS' CONCLUSIONS

There is insufficient evidence on the benefits and harms of fetal assessment methods for improving neonatal and maternal outcomes in women with PPROM to draw firm conclusions. The overall quality of evidence that does exist is poor.Further high-quality randomised controlled trials are required to guide clinical practice.

The uses and limitations of the fetal biophysical profile

In the second half of the twentieth century, true antepartum fetal assessment became possible, mainly due to the advent of real-time ultrasound. Initially, the most widely used form of antepartum fetal assessment was electronic fetal heart rate monitoring, through the nonstress test or the oxytocin-induced contraction stress test. It was soon realized, however, that these forms of monitoring had significant limitations. The biophysical profile allows a more thorough evaluation of fetal well-being and has the potential to significantly reduce the false-positive rate of the nonstress test/contraction stress test.

Influence of oligohydramnios on preterm premature rupture of the membranes at 30 to 36 weeks' gestation

OBJECTIVE

to evaluate the influence of initial oligohydramnios on the prognosis of women with preterm premature rupture of the membranes (PPROM) at 30 to 36 weeks' gestation.

METHODS

the Royal Alexandra Hospital ultrasound database was used to identify singleton pregnancies at 30 to 36 weeks' gestation with an ultrasound performed for confirmed PPROM from January 1992 to December 2006. Records were linked to the electronic provincial delivery record to perform a retrospective cohort study comparing the outcomes of pregnancies with an initial amniotic fluid index (AFI) < 5 cm with the outcomes of pregnancies with an AFI of 5 to 10 cm. Logistic and linear regression were used to analyze the association between binary outcome and explanatory variables.

RESULTS

the maternal and perinatal outcomes of 438 pregnancies were analyzed. Univariate analysis suggested statistically significant associations between initial oligohydramnios and decreased latency (P < 0.001), increased histologically proven chorioamnionitis (P = 0.01), neonatal length of stay in hospital (P = 0.002), and NICU (P = 0.003); however, after controlling for confounding variables (gestational age at delivery, parity, presentation, and antenatal antibiotic and corticosteroid administration), only latency remained significant (P = 0.004). No association was found between initial oligohydramnios and any other outcomes assessed, including mode of delivery, postpartum endometritis, maternal length of stay, non-reassuring fetal status, and neonatal morbidity and mortality.

CONCLUSION

initial oligohydramnios is associated with decreased latency in singleton pregnancies complicated by PPROM at 30 to 36 weeks' gestation; however, it does not appear to influence maternal or neonatal infectious morbidity, and it may not be useful to determine candidacy for expectant management or intentional delivery.

Preterm prelabour amniorrhexis

Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 60% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis and in a high proportion of such cases the underlying cause may be ascending infection from the lower genital tract. The causes of neonatal death in pregnancies with amniorrhexis are prematurity, pulmonary hypoplasia and sepsis. In the management of pregnancies with preterm prelabour amniorrhexis it is essential to distinguish between those with and without intrauterine infection. If there is no infection at presentation it is unlikely that this will develop and in such cases there is no benefit from hospitalisation, bed rest, prophylactic tocolytics or antibiotics. The group with evidence of intrauterine infection go into spontaneous labour within a few days of amniorrhexis; in this group the main determinant for the appropriate management is the gestation at amniorrhexis.

Fetal heart rate monitoring patterns in women with amniotic fluid proteomic profiles indicative of inflammation

We hypothesized that abnormal fetal heart rate monitoring patterns (FHR-MPs) occur more often in pregnancies complicated by intra-amniotic inflammation. Therefore, our objective was to examine the relationships among FHR-MP abnormalities, intra-amniotic inflammation and/or infection, acute histological chorioamnionitis, and early-onset neonatal sepsis (EONS) in pregnancies complicated by preterm birth. Additionally, the ability of various FHR-MPs to predict EONS was investigated. FHR-MPs from 87 singleton premature neonates delivered within 48 hours from amniocentesis (gestational age, mean +/- SD: 28.9 +/- 3.3 weeks) were analyzed blindly using strict National Institute of Child Health and Human Development criteria. Strips were evaluated at three time points: at admission, at amniocentesis, and prior to delivery. Intra-amniotic inflammation was established based on a previously validated proteomic fingerprint (mass-restricted score). Diagnoses of histological chorioamnionitis and EONS were based on well-recognized pathological, clinical, and laboratory criteria. We determined that fetuses of women with severe intra-amniotic inflammation had a higher FHR baseline throughout the entire monitoring period and an increased frequency of a nonreactive FHR-MP at admission. Of all FHR-MPs, a nonreassuring test at admission had 32% sensitivity, 95% specificity, 73% positive predictive value, 77% negative predictive value, and 76% accuracy in predicting EONS. Although a nonreassuring FHR-MP at admission was significantly associated with EONS after correcting for gestational age (odds ratio, 5.6; 95% confidence interval, 1.2 to 26.2; P = 0.030), the majority of the neonates that developed EONS had an overall reassuring FHR-MP. Nonreassuring FHR-MPs at either amniocentesis or delivery had no association with EONS. We conclude that in cases complicated by preterm birth, a nonreassuring FHR-MP at the initial evaluation is a specific but not a sensitive predictor of EONS. An abnormal FHR-MP can thus raise the level of awareness that a fetus with EONS may be born, but it is not a useful clinical indicator of the need for antibiotic treatment of the neonate.

The preterm parturition syndrome

The implicit paradigm that has governed the study and clinical management of preterm labour is that term and preterm parturition are the same processes, except for the gestational age at which they occur. Indeed, both share a common pathway composed of uterine contractility, cervical dilatation and activation of the membranes/decidua. This review explores the concept that while term labour results from physiological activation of the components of the common pathway, preterm labour arises from pathological signalling and activation of one or more components of the common pathway of parturition. The term "great obstetrical syndromes" has been coined to reframe the concept of obstetrical disease. Such syndromes are characterised by: (1) multiple aetiology; (2) long preclinical stage; (3) frequent fetal involvement; (4) clinical manifestations that are often adaptive in nature; and (5) gene-environment interactions that may predispose to the syndromes. This article reviews the evidence indicating that the pathological processes implicated in the preterm parturition syndrome include: (1) intrauterine infection/inflammation; (2) uterine ischaemia; (3) uterine overdistension; (4) abnormal allograft reaction; (5) allergy; (6) cervical insufficiency; and (7) hormonal disorders (progesterone related and corticotrophin-releasing factor related). The implications of this conceptual framework for the prevention, diagnosis, and treatment of preterm labour are discussed.

The NICHD-MFMU antibiotic treatment of preterm PROM study: impact of initial amniotic fluid volume on pregnancy outcome

OBJECTIVE

The purpose of this study was to evaluate the associations between measured amniotic fluid volume and outcome after preterm premature rupture of membranes (PROM).

STUDY DESIGN

This was a secondary analysis of 290 women, with singleton pregnancies, who participated in a trial of antibiotic therapy for preterm PROM at 24(0) to 32(0) weeks. Each underwent assessment of the 4 quadrant amniotic fluid index (AFI) and a maximum vertical fluid pocket (MVP) before randomization. The impact of low AFI (< 5.0 cm) and low MVP (< 2.0 cm) on latency, amnionitis, neonatal morbidity, and composite morbidity (any of death, RDS, early sepsis, stage 2-3 necrotizing enterocolitis, and/or grade 3-4 intraventricular hemorrhage) was assessed. Logistic regression controlled for confounding factors including gestational age at randomization, GBS carriage, and antibiotic study group.

RESULTS

Low AFI and low MVP were identified in 67.2% and 46.9% of women, respectively. Delivery occurred by 48 hours, 1 and 2 weeks in 32.4%, 63.5% and 81.7% of pregnancies, respectively. Both low AFI and low MVP were associated with shorter latency (P < .001), and with a higher rate of delivery at 48 hours, 1, and 2 weeks (P = .02 for each). However, neither test offered significant additional predictive value over the risk in the total population. Low AFI and low MVP were not associated with increased amnionitis. After controlling for other factors, both low MVP and low AFI were associated with shorter latency (P < or = .002), increased composite morbidity (P = .03), and increased RDS (P < or = .01), but not with increased neonatal sepsis (P = .85) or pneumonia (P = .53). Alternatively, after controlling for fluid volume, gestational age, and GBS carriage, the antibiotic study group had longer latency, and suffered less common primary outcomes and neonatal sepsis.

CONCLUSION

Oligohydramnios should not be a consideration in determining which women will be candidates for expectant management or antibiotic treatment when it is identified at initial assessment of preterm PROM remote from term.

An Evidence-Based Approach to the Evaluation and Treatment of Premature Rupture of Membranes: Part I

Preterm premature rupture of membranes (PPROM) occurs in 3% of pregnancies and is responsible for one third of all preterm births. PPROM will affect 120,000 women in the United States each year. It is associated with significant maternal, fetal, and neonatal morbidity and mortality resulting from infection, umbilical cord compression, abruptio placentae, and prematurity. The etiology is multifactorial, but the most significant risk factors are previous preterm birth and previous preterm premature rupture of membranes. Accurate diagnosis is extremely important to assure proper treatment. Evaluation is based on patient history and clinical examination. This review presents the available evidence and grades it according to the U.S. Preventative Task Force recommendations. In part I of this review, the definition, pathophysiology, and methods of PPROM diagnosis are presented. In part II, the management, treatment, neonatal outcome, and the maternal and fetal evaluation of women with PPROM in the presence of cerclage and medical complications is reviewed.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to define the term: preterm premature rupture of membranes, to list the factors associated with premature rupture of membranes, and to outline the tests available for the diagnosis of intra-amniotic infection.

Amniotic Fluid Tumor Necrosis Factor-Alpha Is a Marker for the Prediction of Early-Onset Neonatal Sepsis in Preterm Labor

BACKGROUND

Our purpose was to determine whether amniotic fluid concentrations of tumor necrosis factor-alpha are of value in the prediction of early-onset neonatal sepsis (proven or suspected) in patients with preterm labor and intact membranes.

METHODS

The relationship between amniotic fluid tumor necrosis factor-alpha concentrations and early-onset neonatal sepsis was examined in 59 consecutive patients with preterm labor and intact membranes who delivered preterm neonates within 72 h after transabdominal amniocentesis. Early-onset neonatal sepsis was defined either as the presence of a positive blood culture or as suspected sepsis within 72 h of delivery. Tumor necrosis factor-alpha was determined by enzyme-linked immunosorbent assays.

RESULTS

Patients delivering neonates with early-onset neonatal sepsis had significantly higher median amniotic fluid TNF-alpha concentrations than patients delivering neonates without early-onset neonatal sepsis (p < 0.0005). An amniotic fluid tumor necrosis factor-alpha concentration > or =41 pg/ml had a sensitivity of 82% (23/29) and specificity of 79% (38/48) in the prediction of early-onset neonatal sepsis. Multiple logistic regression indicated that elevated amniotic fluid tumor necrosis factor-alpha (> or =41 pg/ml) was the only independent predictor of early-onset neonatal sepsis (odds ratio 12.9, 95% confidence interval 1.3-125.3, p=0.01) after correction for known confounding variables.

CONCLUSIONS

(1) Amniotic fluid tumor necrosis factor-alpha is a marker for the prediction of early-onset neonatal sepsis in patients with preterm labor and intact membranes. (2) Amniotic fluid tumor necrosis factor-alpha is a better independent predictor of early-onset neonatal sepsis than placental histologic finding or amniotic fluid culture.

The relationship among inflammatory lesions of the umbilical cord (funisitis), umbilical cord plasma interleukin 6 concentration, amniotic fluid infection, and neonatal sepsis

OBJECTIVE

The purpose of this study was to determine whether funisitis (inflammation of the umbilical cord detected by histologic examination of the placenta) is associated with changes in the umbilical cord plasma concentration of interleukin 6, microbial invasion of the amniotic cavity, and neonatal sepsis.

STUDY DESIGN

The relationship among the presence of funisitis, interleukin 6 concentrations in umbilical cord plasma at birth, the results of amniotic fluid culture performed within 3 days of birth, and the occurrence of congenital neonatal sepsis was examined in 315 consecutive singleton preterm births (20-35 weeks' gestation). Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton jelly. The interleukin 6 concentration was measured with a specific immunoassay. Amniocentesis was performed in 106 patients within 3 days of birth. Amniotic fluid was cultured for aerobic and anaerobic bacteria and for mycoplasmas.

RESULTS

(1) Funisitis was present in 25% of patients (78/315). (2) Patients with funisitis had a significantly higher median cord plasma interleukin 6 and a lower gestational age at birth than did those without funisitis (cord interleukin 6: median, 52.4 pg/mL; range, 0.9-19,230 pg/mL; vs median, 4.6 pg/mL; range, 0-18,108 pg/mL; gestational age: median, 31.1 weeks' gestation; range, 21.0-35.0 weeks' gestation; vs median, 32.9 weeks' gestation; range, 21.4-35.0 weeks' gestation; P<.001 for each comparison). (3) A cord plasma interleukin 6 of > or =17.5 pg/mL had a sensitivity of 70% and a specificity of 78% in the identification of funisitis. (4) Microbial invasion of the amniotic cavity and clinical chorioamnionitis were more common among patients with funisitis than among those without funisitis (positive amniotic fluid culture: 53% [20/38]; vs. 12% [8/68]; clinical chorioamnionitis: 18% [14/78]; vs. 4% [9/237]; P<.001 for each comparison). (5) Neonates with funisitis had a significantly higher rate of congenital sepsis than did those without this lesion (12% [8/66] vs. 1% [3/216]; P<.001); this difference remained significant after adjustment for gestational age at birth (odds ratio, 7.2; 95% confidence interval, 1.8-29.0).

CONCLUSION

(1) Umbilical cord plasma interleukin 6 concentrations were higher in neonates born with funisitis than in those without this lesion. (2) Funisitis is associated with amniotic fluid infection, congenital neonatal sepsis, and the fetal inflammatory response syndrome.

A randomized clinical trial of daily nonstress testing versus biophysical profile in the management of preterm premature rupture of membranes

OBJECTIVE

Our purpose was to evaluate the ability of 2 different antepartum testing modalities to predict infectious morbidity in patients with preterm premature rupture of membranes.

STUDY DESIGN

During a 36-month period, patients with preterm premature rupture of membranes (at 23 to 34 weeks of gestation) were randomly assigned to either a daily nonstress test or a biophysical profile, after a 24-hour observational period. We used the original scoring system of Manning et al for the biophysical profile, with a score of </=6 considered abnormal. Nonstress test results were considered abnormal if the test was nonreactive or if the patient had late decelerations or significant variable decelerations; abnormal results led to further evaluation with a biophysical profile. Results of the last test before delivery were evaluated to determine whether infectious complications had been predicted.

RESULTS

One hundred thirty-five patients were enrolled in the study. Demographics, pregnancy characteristics, and neonatal outcomes were similar. Neither the daily nonstress test nor the daily biophysical profile had good sensitivity for predicting infectious complications (39.1% and 25.0%, respectively). However, both had good specificity (84.6% and 92.6%, respectively). Positive and negative predictive values were 52.9% and 75.9%, respectively, for the daily nonstress test and 66.7% and 68.4%, respectively, for the daily biophysical profile. Cost was significantly higher in the daily biophysical profile group. Nonstress testing of patients at <28 weeks' gestation generally required a backup biophysical profile.

CONCLUSION

Neither the daily nonstress test nor the daily biophysical profile had good sensitivity for predicting infectious complications after preterm premature rupture of membranes.

Association of oligohydramnios in women with preterm premature rupture of membranes with an inflammatory response in fetal, amniotic, and maternal compartments

OBJECTIVE

This study was undertaken to examine whether oligohydramnios in women with preterm premature rupture of membranes is associated with evidence of fetal, amniotic, and maternal inflammatory responses.

STUDY DESIGN

Amniotic fluid index was measured before the performance of amniocentesis in patients with preterm premature rupture of membranes. Fifty-nine patients who were delivered of preterm neonates (gestational age </=35 weeks) within 3 days of amniocentesis were included in this study. Amniotic fluid was cultured for aerobic and anaerobic bacteria and for genital mycoplasmas. The intensity of the inflammatory response was evaluated by the following: presence of clinical and histologic chorioamnionitis; amniotic fluid concentrations of interleukin 6, interleukin 1beta, and tumor necrosis factor alpha; amniotic fluid white blood cell count; and interleukin 6 concentrations in umbilical cord plasma at birth. Proinflammatory cytokines were measured with specific and sensitive immunoassays.

RESULTS

Thirty-two percent (19/59) of patients had an amniotic fluid index </=5 cm. Patients with an amniotic fluid index </=5 cm had significantly higher rates of positive amniotic fluid culture results and clinical and histologic chorioamnionitis; higher median amniotic fluid concentrations of interleukin 6, interleukin 1beta, and tumor necrosis factor alpha; and higher median cord plasma concentrations of interleukin 6 than did those with an amniotic fluid index >5 cm (positive amniotic fluid culture result, 79% [15/19] vs 30% [12/40]; clinical chorioamnionitis, 37% [7/19] vs 5% [2/40]; histologic chorioamnionitis, 100% [17/17] vs 69% [24/35]; median amniotic fluid interleukin 6 concentration, 13.5 ng/mL; range, 0.2-142.2 ng/mL vs 3.0 ng/mL and 0.001-115.2 ng/mL; median amniotic fluid interleukin 1beta concentration, 348.0 pg/mL; range, 0.7->80, 000 pg/mL vs 36.6 pg/mL and 0-2075 pg/mL; median amniotic fluid tumor necrosis factor alpha concentration, 132.0 pg/mL; range, 0-1600 pg/mL vs 11.2 pg/mL and 0-1305 pg/mL; median cord plasma interleukin 6 concentration, 49.7 pg/mL; range, 4.4-7400 pg/mL vs 9. 1 pg/mL and 0-5211 pg/mL; P <.05 for each). There was no significant difference between the 2 groups of patients in the mean umbilical artery pH at birth.

CONCLUSION

Oligohydramnios in women with preterm premature rupture of membranes is associated with an inflammatory response in the fetal, amniotic, and maternal compartments.

Ultrasound characteristics of in utero infection

In utero infection of the fetus has become recognized as an important cause of fetal and neonatal morbidity and mortality. Since both anatomic and functional abnormalities have been described in the fetus related to various infections, ultrasonography may be a valuable diagnostic tool in this regard. A complete review of the current literature was undertaken to report available information on this topic. Common pathogens or clinical conditions were selected. The identified data were confounded by the way in which each case originally presented for study. Although certain anomalies were frequently associated with individual organisms, their incidence could not be determined, nor were most specific to that infectious agent. Representative ultrasound images are presented for common and unusual cases.

Biophysical testing in premature rupture of the membranes

The management of pregnancies complicated by premature rupture of the membranes (PROM) should include some type of surveillance for the development of infectious complications. This is a necessity because neonatal sepsis is not heralded by maternal chorioamnionitis in the majority of cases. Fetal biophysical assessment holds promise as a method to assess fetal well-being and predict the development of infectious complications. The frequent use of fetal biophysical profiles in patients with PROM helps to distinguish healthy fetuses from those infected or at high risk of infection. This distinction enables the physician to intervene appropriately and in a timely manner. The recognition of the healthy fetus allows for safe prolongation of pregnancy. This article reviews the published experience using antepartum fetal biophysical monitoring in patients with PROM.