Daniel W. Gauthier

Correlation of amniotic fluid glucose concentration and intraamniotic infection in patients with preterm labor or premature rupture of membranes

Amniotic fluid glucose concentration has previously been suggested as a rapid and sensitive test for diagnosing intraamniotic infection. In this study, 204 patients less than or equal to 34 weeks estimated gestational age with preterm labor or premature rupture of membranes underwent amniocentesis to detect subclinical intraamniotic infection. Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as for Mycoplasma species. Amniotic fluid glucose levels were significantly lower in patients with positive amniotic fluid cultures than in patients with negative cultures (median, 10 mg/dl; range, 1 to 62 mg/dl vs median, 31 mg/dl; range, 2 to 126 mg/dl, respectively; p less than 0.001). In terms of predicting amniotic fluid culture results, an amniotic fluid glucose concentration of less than or equal to 16 mg/dl had a sensitivity of 79%, specificity of 94%, positive predictive value of 87%, and negative predictive value of 90%. The determination of amniotic fluid glucose concentration is useful in detecting subclinical intraamniotic infection in patients less than or equal to 34 weeks estimated gestational age with preterm labor or premature rupture of membranes.

Intrapartum fetal subcutaneous tissue/femur length ratio: An ultrasonographic clue to fetal macrosomia

OBJECTIVE Our purpose was to compare the accuracy of ultrasonographic intrapartum measurement of fetal abdominal circumference, estimated fetal weight, and fetal subcutaneous tissue/femur length ratio in predicting large-for-gestational-age fetuses. STUDY DESIGN A cross-sectional analysis of 173 normal patients delivered of normal, appropriate-for-gestational-age infants (group 1) was performed to determine the normal changes of standard fetal biometric parameters and subcutaneous tissue throughout pregnancy. Measurements of fetal subcutaneous tissue were made at the level of the femoral diaphysis. A second group of 101 well-dated patients had these measurements obtained within 24 hours of delivery (group 2). Large for gestational age was defined as a birth weight > 90th percentile for gestational age. The sensitivity and specificity for prediction of large for gestational age of an intrapartum measurement of an abdominal circumference > 90th percentile, estimated fetal weight > 90th percentile, and fetal subcutaneous tissue/femur length ratio > 2 deviations of the mean was calculated. RESULTS In group 1 the mean gestational age was 31.4 +/- 5.4 weeks (range 17 to 41 weeks). The femur length, abdominal circumference, and fetal subcutaneous tissue correlated well with gestational age (p < 0.0001). The fetal subcutaneous tissue/femur length ratio was stable throughout pregnancy, with a mean of 0.05 +/- 0.014 (range 0.02 to 0.09, R2 0.09). In group 2 mean gestational age was 38 +/- 2.5 weeks (range 30 to 42 weeks). Mean birth weight was 3280 +/- 740 gm (range 1513 to 4801 gm). Nineteen (19%) fetuses were large for gestational age. Significant differences were found between the appropriate- and large-for-gestational-age fetuses for birth weight, abdominal circumference, estimated fetal weight, and fetal subcutaneous tissue/femur length ratio (p < 0.0001). The sensitivity and specificity of the fetal abdominal circumference, estimated fetal weight, and fetal subcutaneous tissue/femur length ratio were 44% and 98%, 68% and 85%, and 82% and 96%, respectively. CONCLUSION The fetal subcutaneous tissue/femur length ratio is a gestational age-independent parameter that has a greater sensitivity than the fetal abdominal circumference or estimated fetal weight formula for the intrapartum identification of large-for-gestational-age fetuses.

Vasa previa: Prenatal diagnosis with transvaginal color Doppler flow imaging

Vasa previa carries a significant risk for fetal exsanguination and death at the time of membrane rupture. The diagnosis is rarely made before the onset of vaginal bleeding. We report the prenatal diagnosis of vasa previa with transvaginal color Doppler flow imaging in an asymptomatic patient with a succenturiate placenta.

Expectant management of premature rupture of membranes with amniotic fluid cultures positive for Ureaplasma urealyticum alone

OBJECTIVE Our purpose was to determine maternal and neonatal outcome in patients with premature rupture of membranes and amniotic fluid cultures positive for Ureaplasma urealyticum alone. STUDY DESIGN Amniocentesis was performed on 225 patients with premature rupture of membranes at < or = 34 completed weeks of gestation. Amniotic fluid was cultured for aerobic and anaerobic bacteria, Mycoplasma hominis, and Ureaplasma urealyticum. Patients with cultures positive for Ureaplasma urealyticum alone were managed expectantly, including erythromycin and daily biophysical profile examinations. RESULTS Thirty-three patients (15%) had amniotic fluid cultures positive for Ureaplasma urealyticum alone, and clinical chorioamnionitis developed in three of these patients. There were no suspected or documented cases of neonatal sepsis. The incidence of infectious morbidity in patients with amniotic fluid cultures positive for Ureaplasma urealyticum alone was not significantly different from that seen in patients with negative cultures. CONCLUSION An amniotic fluid culture positive for Ureaplasma urealyticum alone may not be an indication for a preterm delivery in patients with premature rupture of membranes.

Ultrasonographic detection of abnormal fetal growth with the gestational age-independent, transverse cerebellar diameter/abdominal circumference ratio

OBJECTIVES We prospectively evaluated the accuracy of a gestational age-independent method of detecting abnormal growth, the transverse cerebellar diameter/abdominal circumference ratio, and compared this with standard ultrasonographic methods of growth assessment. STUDY DESIGN We prospectively studied 825 low-risk obstetric patients and 250 patients having risk factors for fetal macrosomia (n = 92) or growth retardation (n = 158). Measured fetal parameters included the biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference, and femur length. The estimated fetal weight, head circumference/abdominal circumference, cerebellar diameter/abdominal circumference, and femur length/abdominal circumference ratios were calculated. Reference curves for these parameters were created from a cross-sectional analysis of the low-risk group. Univariate analysis was used to determine the sensitivity, specificity, predictive values, and odds ratios of each individual parameter in identifying a small- or large-for-gestational-age infant. A multivariate logistic regression model with a variable selection procedure was then used to determine whether significance remained when we controlled for other parameters. RESULTS Within the low-risk group, the transverse cerebellar/abdominal circumference ratio was gestational age independent between 14 and 42 weeks with a mean of 13.68 +/- 0.96. A value exceeding 2 SD of the mean was significantly associated with birth or a small-for-gestational-age infant, being abnormal in 98% and 71% of asymmetrically and symmetrically growth-retarded infants, respectively. Significance was maintained in the multivariate regression model. The ratio was not helpful in detecting the large-for-gestational-age infant. CONCLUSION The fetal transverse cerebellar diameter/abdominal circumference ratio is an accurate, gestational age-independent method of identifying the small-for-gestational-age but not the large-for-gestational-age infant.

Detection of group B streptococcus: Comparison of an optical immunoassay with direct plating and broth-enhanced culture methods

The aim of this study was to compare the diagnostic accuracy of an optical immunoassay (STREP B OIA, Biostar) to direct plating and broth-enhanced culture for the detection of group B streptococcus (GBS) colonization of the lower genital tract in pregnant women. GBS cultures from the lower genital tract were obtained in a prospective fashion using a dual swab transport system from patients with risk factors for perinatal GBS infection. One swab was used to inoculate a trypticase soy agar plate with 5% sheep blood (TSA) and then placed in Lim broth. The other swab was used to perform the Strep B OIA. Growth of GBS by either direct plating or broth-enhanced culture was used as the gold standard for determining GBS colonization. Of the 524 women in the study, 90 women had positive cultures (either TSA or Lim broth). The sensitivity, specificity, positive predictive value, and negative predictive value of the Strep B OIA were 47% (42/90), 96% (416/434), 70% (42/60), 90% (416/464). The sensitivity, specificity, positive predictive value, and negative predictive value of the TSA were 61% (55/90), 100% (434/434), 100% (55/55), 93% (434/469). The sensitivity, specificity, positive predictive value, and negative predictive value of Lim broth were 97% (87/90), 100% (434/434), 100% (87/87), and 97% (434/437). The sensitivity of the Strep B OIA to detect light GBS colonization and heavy GBS colonization, as determined by the TSA, was 53% (19/36) and 90% (17/19), respectively. The Strep B OIA and direct agar plate culture appear to be of limited clinical value due to their poor sensitivities. This study also demonstrates the need to use a selective medium such as Lim broth when assessing for GBS colonization of the lower genital tract.

Acute myocardial infarction associated with prostaglandin

Prostaglandin E2 is rarely associated with serious maternal side effects when used for second-trimester pregnancy termination. Acute myocardial infarction complicating therapeutic pregnancy termination with prostaglandin E2 in a patient with chronic glomerulosclerosis and severe hypertension is reported.

Use of recombinant human erythropoietin (EPO-alfa) in a mother alloimmunized to the Jsb antigen

Erythropoietin (EPO) is a glycoprotein hormone and the principal regulator of erythropoiesis in the fetus, newborn, and adult. EPO-alfa is erythropoietin manufactured by recombinant human DNA technology (rhEPO). After counseling, a pregnant woman with anti-Js(b) in her serum was started on rhEPO (600 U/Kg, biweekly) to prevent anemia secondary to serial donations of her blood for fetal transfusions. After a total of 25 rhEPO infusions and autologous donation of 8 units of whole blood, maternal hemoglobin prior to the elective cesarean section at 37 weeks was 11.3 gm/dL. Serum EPO concentration was determined in paired maternal and fetal blood samples, before ultrasound guided intravascular transfusions, in this alloimmunized Js(b)-negative and another Rh(D) alloimmunized pregnancy to determine possible correlations between maternal and fetal serum EPO. rhEPO prevented anemia in a patient who donated 8 units of blood from 18-37 weeks of pregnancy without inducing adverse biological effects such as hypertension or thrombotic complications in the placenta. Data presented in this study suggest that EPO does not cross the human placenta.

Leukocyte Esterase Activity as a Predictor of Amniotic Fluid Cultures in Preterm Labor

Leukocyte esterase activity has been utilized as a rapid screen for urinary tract infection. The purpose of this study was to evaluate leukocyte esterase activity as a rapid predictor of amniotic fluid culture results in patients with preterm labor. Amniocentesis was performed on 121 patients ≤34 weeks estimated gestation age with preterm labor and no clinical evidence of infection. Gram stain as well as aerobic, anaerobic, and Mycoplasma cultures were performed on the amniotic fluid. Leukocyte esterase activity was determined immediately following amniocentesis with the use of a commercially available test strip. Amniotic fluid cultures were positive in 19 subjects (16%). Leukocyte esterase was significantly more sensitive than Gram stain in detecting positive amniotic fluid culture results (79% vs. 42%, respectively; P < 0.02). Tocolysis was either unsuccessful or discontinued due to a positive Gram stain significantly more often when leukocyte esterase activity was present. Leukocyte esterase activity ...

In Vitro Study of Amniotic Fluid Gram Stain: Effect of Centrifugation

Objective: Gram stain of amniotic fluid (AF) is used to detect intraamniotic infection. The purpose of this study was to determine if centrifugation improved the ability of AF Gram stain to detect bacteria. Methods: AF obtained by amniocentesis from patients with preterm labor (PTL) or preterm premature rupture of membranes (PPROM) was pooled. Individual AF samples as well as the pooled sample had a negative Gram stain for microorganisms or white blood cells (WBCs) and negative cultures. With pure bacterial cultures, a suspension equivalent to a 0.5 McFarland turbidity standard was prepared and then serially diluted in the AF to either 106, 105, 104, or 103 colony forming units (cfu)/ml. Each sample was divided into 2 equal portions, with 1 undergoing centrifugation. The Gram stains were interpreted by technologists in the clinical microbiology laboratory in a blinded fashion. Fishers exact test was used to compare the bacterial detection rate in centrifuged vs. uncentrifuged AF samples at each concentration. Results: Centrifugation of AF significantly improved the ability of the Gram stain to detect bacteria at bacterial concentrations ≤104 cfu/ml (P < 0.01). At concentrations ≥105 cfu/ml, centrifugation did not improve the ability of the Gram stain to dtect bacteria. Conclusions: At low bacterial concentrations, centrifugation of AF increases the bacterial detection rate of AF Gram stain.