Impact of amniotic fluid “sludge” on the risk of preterm delivery

Objective: To evaluate the impact of amniotic fluid “sludge” (AFS) on the risk of preterm delivery and to describe the effect of antibiotic treatment in that situation.

Methods: Case–control study including singleton pregnancies with or without AFS, between 15–32 weeks of gestation. Factors associated with preterm delivery before 32 weeks, 34 weeks and 37 weeks were evaluated with univariate and multivariate logistic regression. Since all women with AFS in this study were treated with antibiotics, a historical comparison was performed with similar patients with AFS found before 2007 and not treated with antibiotics.

Results: AFS was observed in 90/1220 patients (7.4%). AFS was associated with shorter cervical length, greater body mass index, cervical cerclage and preterm birth before 28 weeks. However, after adjustment, AFS did not remain associated with preterm delivery before 32 or 34 weeks. The historical comparison suggested that azithromycin could significantly reduce the risk of preterm delivery before 34 weeks (odds ratio: 0.2; 95% CI: 0.04–0.92).

Conclusions: AFS, treated with azithromycin, was associated with a higher risk of prematurity, but not independently after adjustment for cervical length and second trimester vaginal bleeding. Further studies need to evaluate the effect of antibiotics in pregnancies with AFS.     

Mineral Preservatives in the Wood of Stradivari and Guarneri

Following the futile efforts of generations to reach the high standard of excellence achieved by the luthiers in Cremona, Italy, by variations of design and plate tuning, current interest is being focused on differences in material properties. The long-standing question whether the wood of Stradivari and Guarneri were treated with wood preservative materials could be answered only by the examination of wood specimens from the precious antique instruments. In a recent communication (Nature, 2006), we reported about the degradation of the wood polymers in instruments of Stradivari and Guarneri, which could be explained only by chemical manipulations, possibly by preservatives. The aim of the current work was to identify the minerals from the small samples of the maple wood which were available to us from the antique instruments. The ashes of wood from one violin and one cello by Stradivari, two violins by Guarneri, one viola by H. Jay, one violin by Gand-Bernardel were analyzed and compared with a variety of commercial tone woods. The methods of analysis were the following: back-scattered electron imaging, X-ray fluorescence maps for individual elements, wave-length dispersive spectroscopy, energy dispersive X-ray spectroscopy and quantitative microprobe analysis. All four Cremonese instruments showed the unmistakable signs of chemical treatments in the form of chemicals which are not present in natural woods, such as BaSO₄, CaF₂, borate, and ZrSiO₄. In addition to these, there were also changes in the common wood minerals. Statistical evaluation of 12 minerals by discriminant analysis revealed: a. a difference among all four Cremona instruments, b. the difference of the Cremonese instruments from the French and English antiques, and c. only the Cremonese instruments differed from all commercial woods. These findings may provide the answer why all attempts to recreate the Stradivarius from natural wood have failed. There are many obvious implications with regard to how the green tone wood should be treated, which chould lead to changes in the practice of violin-making. This research should inspire others to analyze more antique violins for their chemical contents.     

First and Third Trimester Uterine Scar Thickness in Women With Previous Caesarean: A Prospective Comparative Study

Background

Lower uterine segment (LUS) thickness in the third trimester of gestation is associated with the risk of uterine scar defect at delivery. It was suggested that first trimester residual myometrial thickness (RMT) could also predict uterine scar defect at delivery.

Cesarean delivery after successful external cephalic version of breech presentation at term: a comparative study

OBJECTIVE: The purpose of this study was to evaluate the rate and indications of cesarean delivery after a successful external cephalic version. STUDY DESIGN: A case-control study was performed from patients who were delivered in a tertiary care center between 1987 and 2000. Each patient who underwent a successful external cephalic version (study group) was compared with the next woman with the same parity, who was delivered at term (control group). Nulliparous and multiparous women were analyzed separately. Chi-squared, Mann-Whitney, and Student t tests were used for statistical analysis. Multivariate logistic regression analysis was performed where appropriate. RESULTS: A total of 602 patients were included in this study. The rates of cesarean delivery in nulliparous women (29.8% vs 15.9%; P<.001) and in multiparous women (15.9% vs 4.7%; P<.001) were significantly higher when compared with the control group. Patients with successful external cephalic version were more likely to have a cesarean delivery for dystocia (nulliparous, 22.5% vs 11.9%; P=.01; multiparous, 10.9% vs 1.3%; P<.01). After an adjustment for confounding variables, a successful external cephalic version was associated with an increased rate of cesarean delivery at term (nulliparous: odds ratio, 2.04; 95% CI, 1.13-3.68; multiparous: odds ratio, 4.30; 95% CI, 1.76-10.54). CONCLUSION: The rate of cesarean delivery for dystocia is increased after a successful trial of external cephalic version in both nulliparous and multiparous women.     

Is abnormal labor associated with shoulder dystocia in nulliparous women?

OBJECTIVE: This study was undertaken to examine the relationship between labor abnormalities and shoulder dystocia in nulliparous women. STUDY DESIGN: Nulliparous women whose delivery was complicated by shoulder dystocia were studied and compared with a control group selected based on the best possible match for race, labor type (spontaneous or induced), and birth weight. The duration of first and second stage of labor, as well as the rates of labor progress, were calculated and compared between groups. RESULTS: During this 4-year study period, there were 8010 nulliparous singleton deliveries of which 65 (0.8%) were complicated by shoulder dystocia. Compared with controls, there was no difference in the rate of cervical dilation in the active phase of the first stage of labor. In the shoulder dystocia group, more patients had a second stage of labor greater than 2 hours (22% vs 3%; P <.05) and had operative vaginal deliveries (26% vs 1.5%; P <.001). In shoulder dystocia cases with birth weight greater than 4000 g, 33% had a second stage of labor greater than 2 hours. CONCLUSION: In our population, the combination of fetal macrosomia, second stage of labor longer than 2 hours and the use of operative vaginal delivery were associated with shoulder dystocia in nulliparous women.     

Trial of labor in patients with a previous cesarean section: does maternal age influence the outcome?

OBJECTIVE: This study was undertaken to evaluate the effect of maternal age on the rate of vaginal delivery and the rate of uterine rupture in patients undergoing a trial of labor (TOL) after a prior cesarean delivery. STUDY DESIGN: A cohort study of all women with a live singleton fetus undergoing a TOL after a previous low-transverse cesarean delivery was performed between 1988 and 2002 in a tertiary care center. Patients were divided into 3 groups according to maternal age: less than 30 years old, 30 to 34 years old, and 35 years or older. Women with no prior vaginal delivery and with at least 1 prior vaginal delivery were analyzed separately. The rate of vaginal delivery and the rate of symptomatic uterine rupture were calculated. Multivariate logistic regression analyses were performed to adjust for potential confounding variables. RESULTS: Of the 2493 patients who met the study criteria, there were 1750 women without a prior vaginal delivery (659, 721, and 370, respectively) and 743 women with a prior vaginal delivery (199, 327, and 217, respectively). The rate of uterine rupture was comparable between the groups (2.0%, 1.1%, 1.4%, P=.404 and 0%, 0.3%, 0.9%, P=.312). Successful vaginal delivery was inversely related to maternal age (71.9%, 70.7%, 65.1%, P=.063, and 91.5%, 91.1%, 82.9%, P=.005). After adjusting for confounding variables, maternal age equal to or greater than 35 years old was associated with a lower rate of successful vaginal delivery in patients without prior vaginal delivery (odds ratio [OR] 0.73, 95% CI: 0.56-0.94), and in patients with a prior vaginal delivery (OR: 0.47, 95% CI: 0.29-0.74). CONCLUSION: Patients who are 35 years or older are more prone to have a failed TOL after a prior cesarean delivery.     

Cervical ripening with transcervical foley catheter and the risk of uterine rupture

OBJECTIVE: To estimate whether the rate of uterine rupture in patients with a previous cesarean delivery is related to labor induction and/or cervical ripening using transcervical Foley catheter. METHODS: Charts of all patients who had a trial of labor after a previous cesarean delivery in our institution between 1988 and 2002 were reviewed. The rates of successful vaginal birth after cesarean delivery and uterine rupture in patients with spontaneous labor (control group) were compared with those of patients who underwent a labor induction by means of amniotomy with or without oxytocin and patients who underwent a labor induction/cervical ripening using a transcervical Foley catheter. Logistic regression analysis was performed to adjust for confounding variables. RESULTS: Of 2479 patients, 1807 had a spontaneous labor, 417 had labor induced by amniotomy with or without oxytocin, and 255 had labor induced by using transcervical Foley catheter. The rate of successful vaginal birth after cesarean delivery was significantly different among the groups (78.0% versus 77.9% versus 55.7%, P <.001), but not the rate of uterine rupture (1.1% versus 1.2% versus 1.6%, P =.81). After adjusting for confounding variables, the odds ratio (OR) for successful vaginal birth after cesarean delivery was 0.68 (95% confidence interval [CI] 0.41, 1.15), and the OR for uterine rupture was 0.47 (95% CI 0.06, 3.59) in patients who underwent an induction of labor using a transcervical Foley catheter when compared with patients with spontaneous labor. CONCLUSION: Labor induction using a transcervical Foley catheter was not associated with an increased risk of uterine rupture.     

Post-marketing surveillance of immediate allergic reactions: polygeline-based versus polygeline-free pediatric TBE vaccine

Scattered cases of immediate allergic reactions occurred in the nineties after widespread use of the original (polygeline-based) pediatric tick-borne encephalitis (TBE) vaccine and were reported to Pharmacovigilance, Chiron Vaccines. Although, still indicating a very rare frequency of about two cases per 100,000 doses sold, the benefit/risk assessment resulted in its withdrawal from the market in early 1998. An intensive evaluation revealed that polygeline used as a vaccine stabilizer was the most probable cause of the reported allergic reactions. Consequently, an improved pediatric TBE vaccine, free of polygeline and other protein-derived vaccine stabilizers, was developed. A post-marketing surveillance analysis covering the first two vaccination seasons after the introduction of this new pediatric TBE vaccine in early 2002 reveals a very low reporting rate of immediate allergic reactions post immunization (within the range as noted for other widely used vaccines for childhood immunization), i.e., 0.08-0.24 cases per 100,000 doses sold depending on case definition and medical assessment. In conclusion, this analysis provides post-marketing surveillance evidence that the change in the vaccine formulation, with regards to the potential risk of immediate allergic reactions, has led to an intended improvement in the vaccine's safety profile.     

The relationship between amniotic fluid index and successful external cephalic version: a 14-year experience

OBJECTIVE: This study was undertaken to assess the association between amniotic fluid index (AFI), success of external cephalic version (ECV), and obstetric outcome in patients undergoing ECV. STUDY DESIGN: A prospective observational study was performed that included all patients who had a trial of ECV from 1987 to 2000 in our center. Rates of success, fetal heart decelerations during trial at ECV, and cesarean deliveries were calculated. Groups were divided by an AFI performed immediately before ECV: AFI less than 10 cm, 10 to 15 cm, and more than 15 cm. RESULTS: In our group of 1361 patients undergoing ECV, the rate of success was related to the AFI in both parous women (49.1%, 63.5% and 72.1% [P<.001] for each AFI group, respectively) and nulliparous women (36.5%, 43.6%, and 57.3% [P<.001]). The rate of cesarean section delivery was related to AFI in nulliparous but not multiparous patients (P<.001). The rate of prolonged fetal heart rate decelerations was not significantly related to the AFI. CONCLUSION: The rate of successful ECV and cesarean section deliveries is related to the amniotic fluid volume. This information may be used to consent patient before a trial of ECV.