Maternal markers for detecting early-onset neonatal infection and chorioamnionitis in cases of premature rupture of membranes at or after 34 weeks of gestation: a two-center prospective study

BACKGROUND

Accurate prediction of infection, including maternal chorioamnionitis and early-onset neonatal infection, remains a critical challenge in cases of preterm rupture of membranes and may influence obstetrical management. The aim of our study was to investigate the predictive value for early-onset neonatal infection and maternal histological and clinical chorioamnionitis of maternal biological markers in routine use at or after 34 weeks of gestation in women with premature rupture of membranes.

METHODS

We conducted a two-center prospective study of all women admitted for premature rupture of membranes at or after 34 weeks of gestation. The association of C-reactive protein, white blood cell count, vaginal sample bacteriological results, and a prediction model at admission, for early-onset neonatal infection and maternal chorioamnionitis were analyzed by comparing areas under the receiver operating characteristic curves and specificity.

RESULTS

The study included 399 women. In all, 4.3% of the newborns had an early-onset neonatal infection and 5.3% of the women had clinical chorioamnionitis. Histological chorioamnionitis was detected on 10.8% of 297 placentas tested. White blood cell counts and C-reactive protein concentrations were significantly associated with early-onset neonatal infection and included in a prediction model. The area under the receiver operating characteristic curve of this model was 0.82 (95% CI [0.72, 0.92]) and of C-reactive protein, 0.80 (95% CI [0.68, 0.92]) (p = 1.0). Specificity was significantly higher for C-reactive protein than for the prediction model (48% and 43% respectively, p < 0.05). C-reactive protein was associated with clinical and histological chorioamnionitis, with areas under the receiver operating characteristic curve of 0.61 (95% CI [0.48, 0.74]) and 0.62 (95% CI [0.47, 0.74]), respectively.

CONCLUSIONS

The concentration of C-reactive protein at admission for premature rupture of membranes is the most accurate infectious marker for prediction of early-onset neonatal infection in routine use with a sensitivity > 90%. A useful next step would be a randomized prospective study of management strategy comparing CRP at admission with active management to assess whether this more individualized care is a safe alternative strategy in women with premature rupture of membranes at or after 34 weeks.

[Nifedipine or nicardipine in management of threatened preterm delivery: an observational population-based study]

OBJECTIVE

For the first line tocolysis, calcium channel blockers (CCB)--oral nifedipine (Adalate®) or intravenous nicardipine (Loxen®)--are frequently used in France. No study compared nifedipine and nicardipine in management of threatened preterm delivery. From data of a French observational study, we compared factors associated with the use of nifedipine and nicardipine. Efficacy and tolerance of the two treatments were also compared.

METHODS

It was a secondary analysis of EVAPRIMA study, a practice survey describing management of threatened preterm delivery in 107 French maternity units. Only women who received calcium channel blockers in their first line tocolytic therapy were included. We studied obstetrical factors associated with the choice of nifedipine or nicardipine. We also analyzed factors associated with a delivery within seven days following admission using univariate and multivariate analysis. Adverse secondary effects were compared between women who received nifedipine or nicardipine.

RESULTS

Three hundred and four women received calcium channel blockers for their first line tocolytic therapy, in 73 maternity units: 93 (30.6%) women received oral nifedipine and 211 (69.4%) intravenous nicardipine. The same CCB was always prescribed in 69 maternity units. Admission after in utero transfer was less frequent among women who received nifedipine (6.5% versus 17.1%, P=0.01). Premature rupture of the membranes was also less frequent among women who received nifedipine (4.3% versus 13.7%, P=0.02), in comparison with women who received nicardipine. Median duration between admission for threatened preterm labor and delivery was longer when nifedipine was used (44 days versus 36 days, P=0.04). After adjustment on obstetrical factors, the risk to have a delivery within 7 days following admission was not significantly different between nifedipine and nicardipine groups (adjusted OR=0.5 [0.2-1.2]). Among women who received nifedipine only two cases (2.1%) of adverse event were reported with only one case needing a switch of treatment. Thirteen (6.2%) cases of adverse event were reported among women who received nicardipine (P=0.16); in three cases it motivated a switch. However, due to bias and limits inherent in such studies, our results should be interpreted cautiously.

CONCLUSION

Nicardipine is the first choice for French obstetricians in management of severe threatened preterm delivery. However, intravenous nicardipine does not increase gestational duration in comparison with oral nifedipine.

Management of threatened preterm delivery in France: a national practice survey (the EVAPRIMA study)

OBJECTIVES

To describe the management of threatened preterm delivery (TPD) in France 3 years after publication of the French guidelines and to analyse the factors of variation of the practices observed.

DESIGN

Population-based study.

SETTING

Representative sample of French maternity units. The study included 107 hospitals, accounting for 20% of all French maternity units.

POPULATION

Women hospitalised for TPD during May 2005.

METHODS

Cross-sectional national practice survey.

RESULTS

Of the 734 admissions for TPD, 12.1% involved premature rupture of membranes and 12.9% were in utero transfers. Women admitted for TPD accounted for roughly 6% of all annual deliveries, regardless of the unit's level of care, and 42.4% of these women delivered preterm: none delivered before 32 weeks in level 1 maternity units, 11.6% in level 2 and 88.4% in level 3. Transvaginal cervical ultrasound was performed for 54.5% of the women with intact membranes. Tocolysis was administered in 87.1% of women with intact membranes, with 45.6% of such women receiving this intervention for longer than 48 hours. First-line tocolytics used were calcium channel blockers (53.7%), beta-agonists (34.7%) or atosiban (8.8%), but their distribution differed substantially according to level of care. Maintenance tocolysis was administered to 385 women (59.8%) with intact membranes. Of the women admitted before 34 weeks, 21.1% did not receive corticosteroids.

CONCLUSIONS

Practices for the management of TPD vary widely and appear to depend on the level of care. Some practices appear less than optimal, especially those related to duration of tocolysis, maintenance tocolysis, antenatal corticosteroid and use of cervical ultrasound.

Selective use of sonographic cervical length measurement for predicting imminent preterm delivery in women with preterm labor and intact membranes

OBJECTIVES

To determine, in a population of women with preterm labor and intact membranes, whether ultrasound cervical length measurement performed only in patients selected according to the Bishop score predicts imminent preterm delivery better than does systematic cervical length measurement in the entire population.

METHODS

The Bishop score and sonographic cervical length were recorded prospectively in women with preterm labor between 24 and 34 completed weeks' gestation. Outcome measures were preterm delivery within 48 h and within 7 days. Predictive values were calculated for each marker separately and then in combination.

RESULTS

Of the study population of 395 women, 17 (4.3%) and 32 (8.1%) delivered within 48 h and within 7 days, respectively, following inclusion. For delivery within 7 days, areas under the Bishop score (0.848) and sonographic cervical length (0.813) receiver-operating characteristics curves did not differ significantly. For the selective use of sonographic cervical length measurement in patients selected according to the Bishop score, the test was considered positive if the Bishop score was >or= 8, or 4-7 with cervical length <or= 30 mm. This test was as sensitive (94%) but more specific (60% vs. 42%, P < 0.001) for predicting preterm birth within 7 days than was sonographic cervical length with a 30-mm cut-off value in the entire population. Results were similar for delivery within 48 h.

CONCLUSION

For predicting imminent preterm delivery in women with preterm labor, measuring sonographic cervical length only in patients with a Bishop score between 4 and 7, compared with a strategy of systematic measurement in the entire population, reduces by 30% the number of false positives and might thus decrease unnecessary therapeutic intervention.

In situ synchrotron far-infrared spectromicroscopy of a copper electrode at grazing incidence angle

Synchrotron far-infrared spectroscopy in situ was successfully carried out on a copper microelectrode using a grazing-angle objective attached to a Bruker IRscope II microscope. The thin-layer spectroelectrochemical cell was constructed out of Teflon and fitted with a 20 microm-thick Mylar window; the copper electrode was 500 microm in diameter. Measurements were carried out in 0.1 M NaOH solution as a function of applied potential between -1.4 and 0 V versus a Hg/Hg2SO(4) reference electrode. Results demonstrate that with the present technique it is possible to obtain in situ spectra with excellent signal-to-noise ratio for surface oxide films formed electrochemically with less than 1 nL of active solution volume. The surface film on copper at 0 V consisted mainly of CuO with possibly some Cu(OH)2 also present. This interpretation is consistent with previous works and thermodynamic calculations.

Detection of interleukin 6 mRNA by RT-PCR in vaginal secretions: association with preterm delivery and neonatal infection in women with preterm labour and intact membranes

OBJECTIVE

To find a biological marker associated with preterm delivery or neonatal infection in pregnant women with preterm labour and intact membranes.

STUDY DESIGN

Cervical secretions were collected from 286 women hospitalized for preterm labour with intact membranes at 24-34 weeks' gestation. The outcomes studied were delivery before 33 and 35 weeks' gestation, chorioamnionitis, and neonatal infection, and their association with the presence of IL-6 mRNA in cervical secretions as detected by RT-PCR. The other infectious markers tested were: bacterial vaginosis and fetal fibronectin in cervical secretions; serum CRP and white blood cell count.

RESULTS

The vaginal secretions of 13 of 286 women (4.7%) contained IL-6 mRNA. The only other marker tested significantly associated with IL-6 mRNA+ was the presence of streptococcus in vaginal secretions (30.8% versus 9.4% in the IL-6+ and-groups, p = 0.03). Although the difference did not reach statistical significance (p<0.06 and 0.08, respectively), in women with IL-6 mRNA in cervical secretions we observed a tendency to give birth before 33 and 35 weeks more often than the population as a whole. This group was at higher risk of neonatal infection (38.5% versus 15.1%; p = 0.04). After adjustment for infectious risk factors, IL-6 remained significantly associated with neonatal infection (OR = 4.6, 95% CI [1.1-18.9]). The sensitivity of IL-6 mRNA for neonatal infection was 11.1%. The specificity was 96.7%.

CONCLUSION

The detection of IL-6 mRNA by RT-PCR in vaginal secretions allows identification of a small group of women at high risk of neonatal infection, independently of other markers of infection.

Selective use of fetal fibronectin detection after cervical length measurement to predict spontaneous preterm delivery in women with preterm labor

OBJECTIVE

The purpose of this study was to determine whether selective use of fetal fibronectin detection after ultrasound measurement of cervical length predicts preterm delivery in symptomatic patients better than either indicator alone.

STUDY DESIGN

This prospective blinded study performed both tests on 359 women hospitalized for preterm labor between 18 and 34 completed weeks' gestation. The primary outcome was preterm delivery before 35 weeks'gestation.

RESULTS

Among the 359 women included, 48 (13.4%) delivered before 35 weeks' gestation. The sensitivity, specificity, and positive and negative predictive values of cervical length < or = 25 mm were 75%, 63%, 24%, and 94%, respectively, and of fetal fibronectin > or = 50 ng/mL, 63%, 81%, 33%, and 93%. Fetal fibronectin detection was significantly (P < .001) more specific than cervical length measurement. For selective use of fetal fibronectin detection after cervical length measurement, the test was considered positive if cervical length was < or = 15 mm or if cervical length was between 16 and 30 mm with fetal fibronectin > or = 50 ng/mL. The predictive values of this test were not significantly different from those of fetal fibronectin detection (67%, 81%, 36%, and 94%). This strategy could have avoided 200 fibronectin tests.

CONCLUSION

Selective use of fetal fibronectin detection after cervical length measurement is more specific than cervical length and as effective as fetal fibronectin assays in the entire population of women in preterm labor for predicting preterm birth.

Cervical assessment at 22 and 27 weeks for the prediction of spontaneous birth before 34 weeks in twin pregnancies: is transvaginal sonography more accurate than digital examination?

OBJECTIVES

This study compared the accuracy of ultrasound cervical assessment (cervical length and cervical index) and digital examination (Bishop score and cervical score) in the prediction of spontaneous birth before 34 weeks in twin pregnancies.

METHODS

In a prospective multicenter study, digital examination and transvaginal sonography were performed consecutively in twin pregnancies attending for routine sonography at either 22 weeks (175 women) or 27 weeks (153 women). The digital examination took place first, and the Bishop score and cervical score (cervical length minus cervical dilatation) were calculated. Ultrasound measurements were then made of cervical length and funnel length to yield the cervical index (1 + funnel length/cervical length). The association between each variable and delivery before 34 weeks was tested by the Mann-Whitney U-test. The receiver-operating characteristics (ROC) curves of the ultrasound and digital indicators were determined for both gestational age periods, and the areas under the ROC curves compared. The best cut-off values for each indicator were used to determine predictive values for delivery before 34 weeks.

RESULTS

The median gestational age at delivery among the women included in the 22-week examination period was 36.0 (range, 21-40) weeks; 10.9% (19) gave birth spontaneously before 34 weeks. The median cervical length was 40 (range, 6-65) mm. All four parameters were predictors of delivery before 34 weeks. The areas under the ROC curves for cervical index, cervical length, Bishop score and cervical score did not differ significantly. The median gestational age at delivery among the women in the 27-week examination period was 36.0 (range, 27-40) weeks; 9.2% (14) gave birth spontaneously before 34 weeks. The median cervical length was 35 (range, 1-57) mm. All parameters except the Bishop score were predictors of delivery before 34 weeks. The likelihood ratio of the positive and negative tests for cervical length < or = 25 mm was 5.4 (range, 3.2-9.0) and 0.3 (range, 0.1-0.7), respectively, compared with 2.3 (range, 1.3-4.2) and 0.6 (range, 0.3-1.1), respectively, for cervical score < or = 1. The area under the curve for the cervical index was significantly larger than that for the Bishop score (P = 0.008) or cervical score (P = 0.02).

CONCLUSION

Transvaginal sonography predicted spontaneous delivery before 34 weeks better than digital examination at the 27-week but not the 22-week examination.

Ru-Decorated Pt Surfaces as Model Fuel Cell Electrocatalysts for CO Electrooxidation

This feature article concerns Pt surfaces modified (decorated) by ruthenium as model fuel cell electrocatalysts for electrooxidation processes. This work reveals the role of ruthenium promoters in enhancing electrocatalytic activity toward organic fuels for fuel cells, and it particularly concerns the methanol decomposition product, surface CO. A special focus is on surface mobility of the CO as it is catalytically oxidized to CO(2). Different methods used to prepare Ru-decorated Pt single crystal surfaces as well as Ru-decorated Pt nanoparticles are reviewed, and the methods of characterization and testing of their activity are discussed. The focus is on the origin of peak splitting involved in the voltammetric electrooxidation of CO on Ru-decorated Pt surfaces, and on the interpretative consequences of the splitting for single crystal and nanoparticle Pt/Ru bimetallic surfaces. Apparently, screening through the literature allows formulating several models of the CO stripping reaction, and the validity of these models is discussed. Major efforts are made in this article to compare the results reported by the Urbana-Champaign group and the Munich group, but also by other groups. As electrocatalysis is progressively more and more driven by theory, our review of the experimental findings may serve to summarize the state of the art and clarify the roads ahead. Future studies will deal with highly dispersed and reactive nanoscale surfaces and other more advanced catalytic materials for fuel cell catalysis and related energy applications. It is expected that the metal/metal and metal/substrate interactions will be increasingly investigated on atomic and electronic levels, with likewise increasing participation of theory, and the structure and reactivity of various monolayer catalytic systems involving more than two metals (that is ternary and quaternary systems) will be interrogated.

Previous induced abortions and the risk of very preterm delivery: results of the EPIPAGE study

OBJECTIVES

To evaluate the risk of very preterm birth (22-32 weeks of gestation) associated with previous induced abortion according to the complications leading to very preterm delivery in singletons.

DESIGN

Multicentre, case-control study (the French EPIPAGE study).

SETTING

Regionally defined population of births in France.

SAMPLE

The sample consisted of 1943 very preterm live-born singletons (< 33 weeks of gestation), 276 moderate preterm live-born singletons (33-34 weeks) and 618 unmatched full-term controls (39-40 weeks).

METHODS

Data from the EPIPAGE study were analysed using polytomous logistic regression models to control for social and demographic characteristics, lifestyle habits during pregnancy and obstetric history. The main mechanisms of preterm delivery were classified as gestational hypertension, antepartum haemorrhage, fetal growth restriction, premature rupture of membranes, idiopathic preterm labor and other causes.

MAIN OUTCOME MEASURES

Odds ratios for very preterm birth by gestational age and by pregnancy complications leading to preterm delivery associated with a history of induced abortion.

RESULTS

Women with a history of induced abortion were at higher risk of very preterm delivery than those with no such history (OR + 1.5, 95% CI 1.1-2.0); the risk was even higher for extremely preterm deliveries (< 28 weeks). The association between previous induced abortion and very preterm delivery varied according to the main complications leading to very preterm delivery. A history of induced abortion was associated with an increased risk of premature rupture of the membranes, antepartum haemorrhage (not in association with hypertension) and idiopathic spontaneous preterm labour that occur at very small gestational ages (< 28 weeks). Conversely, no association was found between induced abortion and very preterm delivery due to hypertension.

CONCLUSION

Previous induced abortion was associated with an increased risk of very preterm delivery. The strength of the association increased with decreasing gestational age.

Interleukin-8 mRNA in vaginal secretions: a prenatal marker of congenital infection in case of preterm labor with intact membranes

OBJECTIVE

To study whether interleukin-8 (IL-8) mRNA in vaginal secretions is associated with congenital infection and preterm delivery in the case of preterm labor with intact membranes.

METHODS

This prospective clinical study in a tertiary referral center included 280 patients who gave birth to 360 infants from 1997 through 1999. IL-8 mRNA in vaginal secretions was determined with reverse transcriptase polymerase chain reaction. Logistic regression was used to examine the association between vaginal IL-8 mRNA and congenital infection independently of the time of birth. Main outcome measures were congenital infection and delivery before 37 and 33 weeks' gestation.

RESULTS

A total of 100 women (100/280 (35.7%)) gave birth before 37 weeks. A total of 54 children (54/360 (15%)) had congenital infection. IL-8 mRNA in vaginal secretions was associated with delivery within 14 days of the sampling (24 (15.6%) vs. 7 (5.6%) p < 0.01), but not with delivery within 48 h, 7 days (p = 0.07) or before 37 or 33 weeks. There were more congenital infections in the group with detectable IL-8 mRNA (37 (19.3%) than in the negative group (17 (10.1%); p < 0.05). IL-8 mRNA was associated with congenital infection independently of the time of birth (OR: 2.6 (1.3-5.1)). This test had a sensitivity for predicting neonatal infection of 69%. Its specificity was 49%, its positive predictive value 19%, and its negative predictive value 90%.

CONCLUSION

IL-8 mRNA could be a prenatal noninvasive vaginal marker of congenital infection.

Survival of very preterm infants: Epipage, a population based cohort study

OBJECTIVE

To evaluate the outcome for all infants born before 33 weeks gestation until discharge from hospital.

DESIGN

A prospective observational population based study.

SETTING

Nine regions of France in 1997.

PATIENTS

All births or late terminations of pregnancy for fetal or maternal reasons between 22 and 32 weeks gestation.

MAIN OUTCOME MEASURE

Life status: stillbirth, live birth, death in delivery room, death in intensive care, decision to limit intensive care, survival to discharge.

RESULTS

A total of 722 late terminations, 772 stillbirths, and 2901 live births were recorded. The incidence of very preterm births was 1.3 per 100 live births and stillbirths. The survival rate for births between 22 and 32 weeks was 67% of all births (including stillbirths), 85% of live births, and 89% of infants admitted to neonatal intensive care units. Survival increased with gestational age: 31% of all infants born alive at 24 weeks survived to discharge, 78% at 28 weeks, and 97% at 32 weeks. Survival among live births was lower for small for gestational age infants, multiple births, and boys. Overall, 50% of deaths after birth followed decisions to withhold or withdraw intensive care: 66% of deaths in the delivery room, decreasing with increasing gestational age; 44% of deaths in the neonatal intensive care unit, with little variation with gestational age.

CONCLUSION

Among very preterm babies, chances of survival varies greatly according to the length of gestation. At all gestational ages, a large proportion of deaths are associated with a decision to limit intensive care.