Jorge E. Tolosa

Prediction of preterm delivery with transvaginal ultrasonography of the cervix in patients with high-risk pregnancies: does cerclage prevent prematurity?

OBJECTIVESnWe sought to determine the predictive accuracy for preterm delivery of transvaginal ultrasonography of the cervix between 14 and 24 weeks gestation in high-risk patients and to determine whether cerclage prevents preterm delivery in patients with ultrasonographic cervical changes.nnnSTUDY DESIGNnPatients with asymptomatic singleton pregnancies at high risk for preterm delivery were followed prospectively from 14 weeks to 23 weeks 6 days gestation with transvaginal ultrasonography of the cervix. The subgroup of patients with either a cervical length of <25 mm or funneling of >25% or both was offered McDonald salvage cerclage, which was performed at the discretion of the patient and the obstetrician. The 2 groups (with and without cerclage) were compared for the primary outcome of preterm delivery at <35 weeks gestation.nnnRESULTSnOne hundred sixty-eight women were followed, including 97 (58%) with >/=1 prior 14- to 34-week preterm deliveries. Of 63 (37. 5%) patients identified as having cervical changes, 23 (37%) had preterm delivery; of 105 patients with no cervical changes, 8 (8%) had preterm delivery (relative risk, 4.8; 95% confidence interval, 2. 3-10.1). The sensitivity, specificity, and positive and negative predictive values of either a short cervix of <25 mm or funneling of >25% or both were 74%, 70%, 37%, and 92%, respectively. Of 63 pregnancies in which there were cervical changes, 39 underwent cerclage and 24 did not. These 2 groups were similar for demographic characteristics, risk factors, and transvaginal ultrasonographic cervical length and funneling but dissimilar for gestational age at identification of cervical changes (18.3 vs 21.2 weeks gestation in the groups with and without cerclage, respectively; P <.001). Multivariate logistic regression analysis after adjustment for gestational age at cervical changes showed no difference in the rate of preterm delivery between the groups with and without cerclage (odds ratio, 1.1; 95% confidence interval, 0.3-4.6). Stratified analysis of patients identified between 18 and 24 weeks revealed 22 pregnancies with cerclage and 22 pregnancies without cerclage, which was similar for all characteristics studied. The incidence of preterm delivery remained similar (27% vs 23%, respectively; P =.7), as did days from cervical changes to delivery (111 vs 96, respectively; P =.2).nnnCONCLUSIONSnTransvaginal ultrasonography of the cervix between 14 and 24 weeks gestation is a good predictor of preterm delivery in high-risk pregnancies. Cerclage may not prevent preterm delivery in patients identified to be at high risk for this outcome by transvaginal ultrasonography.

Ultrasound assessment of the cervix.

Ultrasound of the Cervix—Techniques Initial attempts at evaluating the cervix used transabdominal ultrasound (TAU). Unfortunately, this technique was found to be imperfect, because of (1) fetal parts obscuring the cervix, especially after 20 weeks, (2) the requirement of bladder filling, which can elongate the cervix and mask funneling, and (3) long distance from the probe to the cervix. Translabial (also known as transperineal) ultrasound, first used in France in the early 1980s, proved to be more useful. This technique involves having the patient lie on table with the hips and knees flexed, while a gloved transducer is positioned on the perineum in a sagittal orientation between the patient’s labia majora. Elevation of the patient’s hips with a cushion is sometimes used to improve visualization. Compared with TAU, this technique is not impaired by obstruction by fetal parts, and does not require bladder filling, achieving close to 100% visualization. Other advantages of this technique are that the transducer is closer to the cervix, but does not enter the vagina (so no pressure can be exerted on the cervix), it Correspondence: Vincenzo Berghella, MD, Division of Maternal–Fetal Medicine, Department of Obstetrics and Gynecology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania. E-mail:vincenzo.berghella@jefferson.edu CLINICAL OBSTETRICS AND GYNECOLOGY Volume 46, Number 4, 947–962

International survey on variations in practice of the management of the third stage of labour.

OBJECTIVEnTo determine the use of the active management of the third stage of labour in 15 university-based obstetric centres in ten developing and developed countries and to determine whether evidence-based practices were being used.nnnMETHODSnFrom March 1999 to December 1999, the Global Network for Perinatal and Reproductive Health (GNPRH) conducted an observational, cross-sectional survey to assess the use of the practice and its components. Prospective data on patient characteristics and the interventions used in the management of the third stage of labour were collected using standardized methods. Data on approximately 30 consecutive vaginal deliveries in each centre (452 in total) were included.nnnFINDINGSnSignificant intracountry and intercountry variation in the practice of the active management of the third stage of labour was found (111/452 deliveries used active management), which confirmed the existence of a large gap between knowledge and practice.nnnCONCLUSIONnAreas identified for improvement are the urgent implementation of the evidence-based clinical management practice defined as the active management of the third stage of labour; increased accessibility to systematic reviews in developing countries; and the conduction of clinical trials that assess the impact of this intervention in other settings.

Reproducibility of Fetal Lung Volume Measurements With 3-Dimensional Ultrasonography

Objective. To build a nomogram of normal fetal lung volumes and to assess the reproducibility of measurements using 3‐dimensional ultrasonography. Methods. Inclusion criteria were healthy women, singleton normal pregnancies, reliable dating, and 20 to 30 weeks gestation. Exclusion criteria were discordance between clinical and ultrasonographic dating, patients lost to follow‐up, and birth weight disorders. Patients were scanned at intervals longer than 2 weeks. Three volumes were acquired for each patient; only data from the volume with the best image quality was used for analysis. Volumes were rated and measured by the manual tracing method. We recorded whether the clavicle was visualized. Only good‐quality volumes were included in analysis. The best volume was chosen, and each lung was measured. Results. A total of 75 patients were studied over a 9‐month period, from which 182 volumes were analyzed. Of the 182 volumes, 15 (8.2%) were excluded for poor quality. The remaining 167 volumes were included in the final analysis. In 83 volumes (50%), the clavicle was not visualized. The best fit for total lung volume was a second‐degree polynomial regression curve. Lung volume was 10.28 mL at 20 weeks and 51.49 mL at 30 weeks. Assessment of agreement was studied by selection of 40 volumes. Intraobserver variability was 5.48 mL (10.6%) and 3.07 mL (5.96%). Interobserver variability was 7 mL. Conclusions. Our findings suggest that 3‐dimensional ultrasonographically derived measurements are reliable and reproducible up to 30 weeks if a standard measurement technique is used.

Subclinical myocardial injury in small-for-gestational-age neonates

Objective: Small-for-gestational-age (SGA) infants are at risk for premature death from cardiovascular disease (myocardial infarction and stroke), hypertension, and diabetes in adult life. Severe intrauterine growth restriction is often associated with subclinical cardiovascular abnormalities detectable during fetal echocardiography. The objective of this study was to determine whether SGA newborns have evidence of myocardial injury at birth. Study design: Cardiac troponin I, a specific marker of myocardial injury widely used for the diagnosis of myocardial infarction in adults, was determined in umbilical cord blood. Umbilical cord venous blood was obtained at the time of birth from 72 SGA newborns (birth weight below the 10th centile for gestational age) and 309 newborns whose birth weights were appropriate for gestational age (AGA). Cardiac troponin I was determined with a commercially available immunoassay (sensitivity 0.2 ng/ml) employed in clinical laboratories (Immulite 2000, Diagnostic Products Corp., Los Angeles, CA). Results: Cardiac troponin I was not detectable in any of the blood samples from AGA infants. In contrast, 4.2% (3/72) of SGA infants had detectable cardiac troponin I in umbilical cord blood (Fishers exact test, p = 0.007). Conclusion: A subgroup of SGA newborns undergoes myocardial injury before birth. This insult may predispose to the development of adult premature cardiovascular disease and death.

Random urinary protein-to-creatinine ratio for prediction of significant proteinuria in women with preeclampsia

OBJECTIVEnTo evaluate the accuracy of random urinary protein-to-creatinine ratio for prediction of significant proteinuria in women with suspected preeclampsia.nnnMETHODSnA prospective study was conducted in hospitalized pregnant women with a suspicion of preeclampsia. Random mid-stream urine specimens were obtained for protein-to-creatinine ratio determination, and then participants were instructed to collect 24-h urine samples for protein measurement. With the criterion of 24-h proteinuria of at least 300 mg as a significant proteinuria, the sensitivity and specificity of a random urinary protein-to-creatinine ratio of > or = 0.19 for prediction of significant proteinuria were analyzed and a receiver operating characteristic curve was constructed to determine the optimal cutoff value.nnnRESULTSnForty-two patients completed the study. Sixty-nine percent of the study population had significant proteinuria. A cutoff of 0.19 demonstrated a sensitivity of 100% and a specificity of 53.8%. A ratio below 0.22 could rule out a significant proteinuria. The optimal cutoff value is 0.25 which yielded sensitivity, specificity and accuracy of 96.6%, 92.3% and 95.2% respectively.nnnCONCLUSIONnIn hospitalized preeclamptic patients, the random urinary protein-to-creatinine ratio at a cutoff of > or = 0.25 revealed a highly accurate prediction of significant proteinuria and could be a more practical alternative for assessment of proteinuria.

An international survey of practice variation in the use of antibiotic prophylaxis in cesarean section.

Objective: To examine the use of antibiotic prophylaxis in cesarean section in different countries and in relation to a reference regimen. Method: Fifty consecutive cesarean sections performed in eight centers in five countries were surveyed. Data from each center were compared to a regimen recommended by the Cochrane Collaboration (one dose of ampicillin or cefazolin administered to all women shortly before the procedure or immediately after cord clamping) using logistic regression with adjustment for procedure type. Result: Prophylaxis was used widely, but only four centers administered prophylaxis to all women. Ampicillin and cefazolin were the principal antibiotics used, but broad‐spectrum agents and multidrug regimens were also used commonly. Only two centers reliably administered the antibiotic at the appropriate time. The majority of women received only one dose of antibiotic in only three centers. Conclusion: The use of antibiotic prophylaxis in cesarean section was variable and often at odds with published recommendations.

Non‐obstetric surgery during gestation: Risk factors for lower birthweight

Objective: To assess the risk for preterm birth and low birthweight for women undergoing non‐obstetric surgery during gestation.

The International Infections in Pregnancy Study: group B streptococcal colonization in pregnant women

Background: Heavy colonization with group B streptococcus (GBS) has been associated with increased risk of preterm birth and neonatal sepsis; the burden of neonatal GBS disease varies geographically. To determine whether variation in heavy colonization and GBS serotypes could contribute to geographic differences in disease burden, we assessed the prevalence of heavy colonization and the distribution of serotypes in asymptomatic pregnant women in multiple countries. Methods: Cervical, lower vaginal and urine samples were collected from women attending seven prenatal clinics in six countries. Light colonization was defined as GBS isolation from Lim broth only; heavy colonization was isolation from urine or sheep blood agar plates. Isolates were serotyped using capillary precipitation. Results: GBS was present in 11.3% of 1308 participants (range 7.1–21.7%); 5.0% were heavily colonized (0.4–18.8%) and 6.4% were lightly colonized (2.9–8.0%). Serotypes III and V were most common (both 17.2%). Serotypes VII and VIII were found in one study center. Conclusions: The prevalence of heavy colonization and GBS serotypes varied significantly among our study centers. Whether this variation could in part explain geographic differences in neonatal morbidity and mortality is a hypothesis that needs further study.

Elevated monocyte chemotactic protein-1 in amniotic fluid is a risk factor for pregnancy loss

Objective: Pregnancy loss after mid-trimester amniocentesis occurs in 0.5–1% of cases and is frequently attributed to the procedure. Accumulating evidence implicates a pre-existing, but clinically silent, intra-amniotic inflammation in the etiology of adverse pregnancy outcome after mid-trimester amniocentesis. Monocyte chemotactic protein-1 (MCP-1) is a potent chemokine produced by a wide variety of cells during the course of an inflammatory response. This study was designed to assess if the amniotic fluid concentration of this chemokine identifies patients at risk for spontaneous abortion and/or fetal death. Method: A retrospective case–control study of women who had a mid-trimester amniocentesis was designed. Cases (n = 10) consisted of patients who had a spontaneous pregnancy loss after the procedure, while the control group (n = 84) consisted of patients who had a normal pregnancy outcome after mid-trimester amniocentesis. MCP-1 was measured by a specific enzyme immunoassay (sensitivity, 18.3 pg/ml). The Kolmogorov–Smirnov test was utilized to assess normal distribution of the data. Logarithmic transformation was applied to achieve normality. Statistical analysis was performed using Students t test. A receiver operating characteristic (ROC) curve analysis was used to select a cut-off to dichotomize amniotic fluid concentrations of MCP-1. Results: MCP-1 was detectable in all amniotic fluid samples. Patients who had a mid-trimester amniocentesis and a subsequent pregnancy loss had a higher mean amniotic fluid log MCP-1 concentration than those with a normal pregnancy outcome (pregnancy loss, mean 2.95 ± 0.19 pg/ml vs. normal outcome, mean 2.78 ± 0.19 pg/ml; p = 0.01). A cut-off of > 765 pg/ml was selected by ROC curve analysis (area under the curve, 0.74; p = 0.01). An amniotic fluid concentration of MCP-1 above this level was strongly associated with pregnancy loss (odds ratio, 7.35; 95% confidence interval, 1.7–31.1), a sensitivity of 70%, and a specificity of 76%. Conclusion: A subset of women who had a pregnancy loss after a mid-trimester amniocentesis had higher concentrations of the chemokine MCP-1 than those who had a normal pregnancy outcome. Subclinical intra-amniotic inflammation is a risk factor for pregnancy loss after mid-trimester amniocentesis. This observation may have medicolegal and clinical implications. An elevated MCP-1 concentration in amniotic fluid of patients with a pregnancy loss after a mid-trimester amniocentesis indicates that a pathological condition was present at the time of the procedure.