Ultrasonographic fetal cardiac measurement in isoimmunized pregnancies.

OBJECTIVE: To investigate the predictive value of the ultrasonographically measured fetal biventricular outer dimension (BVOD) in diastole in detecting neonatal anemia in pregnancies complicated by isoimmunization. STUDY DESIGN: The records of all patients evaluated for isoimmunization in pregnancy from January 1992 to December 1994 were reviewed retrospectively. The fetal BVOD had been measured with real-time-directed M-mode fetal echocardiography. The BVOD measurement was plotted on a nomogram (with reference to biparietal diameter) and a percentile value determined graphically from the nomogram. Neonatal outcome was obtained prospectively and by chart review. RESULTS: Sixty-three singleton fetuses from the study period who met entry criteria were identified. Anti-D sensitization represented 66% of cases of isoimmunization. Twenty (32%) fetuses required subsequent neonatal transfusion, and 43 (68%) did not. Seventeen fetuses (27%) had BVOD measurements greater than the 95th percentile, and 10 (59%) required subsequent transfusion. Infants in this group also had significantly lower hematocrits at birth (37.7 +/- 13.0% vs. 46.6 +/- 9.0%) and prolonged neonatal intensive care unit stay (10.7 +/- 10.0 vs. 4.7 +/- 3.6 days), respectively, when compared to patients with a BVOD measurement less than the 95th percentile. A BVOD 95th percentile threshold had a sensitivity, specificity and positive predictive value of 50%, 84% and 59%, respectively, in predicting the need for neonatal transfusion. CONCLUSION: In patients with isoimmunization, a BVOD measurement in the 95th percentile or greater was associated with a relatively high likelihood of neonatal anemia and transfusion. Although the measurement is not sufficiently sensitive to be used as a single parameter in predicting neonatal compromise in these patients, it can be a useful, noninvasive adjunct to the management of isoimmunized pregnancies.

Clinical significance of prenatal ultrasonographic intestinal dilatation in fetuses with gastroschisis.

OBJECTIVE: Our purpose was to evaluate the clinical significance of intestinal dilatation detected by prenatal ultrasonographic examination in fetuses with gastroschisis. STUDY DESIGN: A retrospective chart review was performed of all patients cared for at Los Angeles County/University of Southern California Women's and Children's Hospital with the prenatal diagnosis of gastroschisis over a 7-year period (1988 through 1995). Patients were divided into two groups on the basis of the presence or absence of ultrasonographically measured fetal bowel diameter of > or = 17 mm. Neonatal outcomes of the two groups were compared. RESULTS: Twenty-one patients met the entry criteria during the study period. Fetuses with maximal bowel diameter of > or = 17 mm did not have a longer time to full oral feeding, a longer initial hospital stay, or a greater need for bowel resection when compared with fetuses with a bowel diameter < 17 mm. Two newborns underwent bowel resection because of intestinal atresia. Prenatal ultrasonographic examination failed to show significant bowel dilatation in either infant. CONCLUSION: Our data suggest that prenatal evidence of intestinal dilatation in fetuses with gastroschisis does not predict immediate neonatal outcome. Thus this finding is not an appropriate indication for preterm delivery in the absence of other evidence of fetal compromise.

The nonreactive nonstress test: predictive value for neonatal anemia in the isoimmunized pregnancy.

OBJECTIVE: To assess the value of the fetal nonstress test (NST) in predicting neonatal transfusion in pregnancies complicated by red cell isoimmunization. METHODS: We retrospectively reviewed the records of all patients evaluated for isoimmunization in pregnancy for the period January 1992 to December 1994. In addition to prenatal care, serial ultrasonography, and invasive testing when indicated, patients had NSTs two times per week. Nonstress tests were interpreted as either reactive or nonreactive using standard criteria. Results of the last NST before delivery were analyzed. Neonatal outcome data were obtained prospectively and by chart review. RESULTS: Sixty patients with isoimmunization were identified during the study period. Fifty-one patients (85%) had reactive NSTs until delivery, and nine (15%) had nonreactive NSTs that prompted delivery. Twelve of 51 (23.5%) patients with reactive NSTs and seven of nine (77.8%) patients with nonreactive NSTs required neonatal transfusion (P = .003, odds ratio 11.4 [95% confidence interval (CI) 1.7-120.2]). The mean (standard error of the mean; range) hematocrit (%) at birth was 38.9 (3.0; 21.3-52.0) in patients with reactive NSTs and 28.3 (3.8; 14.5-45.0) in those with nonreactive NSTs (P < .05). A nonreactive NST had a 77.8% positive predictive value (95% CI 49.0-100) in identifying the need for neonatal transfusion. CONCLUSION: These findings indicate that a nonreactive NST is predictive of subsequent neonatal transfusion in patients with isoimmunization. The antepartum fetal NST is a useful adjunct in the management of isoimmunized pregnancies.

Chromosome analysis in spontaneous pregnancy loss: use of placental villus mesodermal core cell cultures.

Culture of placental villus mesodermal core cells, a method developed for chorionic villus sampling, was used for cytogenetic analysis in 168 spontaneous pregnancy losses. Successful karyotype results were obtained in 72% of cases and 87.5% of cases in which placental tissue was available. Culture of placental villus mesodermal core cells is useful in the evaluation of spontaneous pregnancy loss, particularly when tissues of direct fetal origin are unavailable or unsuitable for culture. Details of culture and specimen handling techniques are provided.

Fetal biometry as a screening tool for the detection of chromosomally abnormal pregnancies.

Recent studies suggest that fetal biometry may allow recognition of pregnancies at risk for Down syndrome. Second-trimester biparietal diameter (BPD)/femur length and observed-to-expected femur length ratios were examined in 48 chromosomally abnormal fetuses and compared with those of a control population composed of both low-risk patients (maternal age less than 35 years) and high-risk patients (maternal age 35 years or more). Biparietal diameter/femur length ratio correctly identified 18% of Down syndrome pregnancies with a positive predictive value of one in 169 and a false-positive rate of only 4%. When trisomies 21, 18, and 13 were considered collectively, a sensitivity of 29% and a predictive value of one in 78 were achieved, with no increase in the false-positive rate (4%). Observed-to-expected femur length ratio was less valuable in detecting chromosomally abnormal fetuses. These data suggest that the BPD/femur length ratio holds promise as a screening tool for the antenatal detection of fetal chromosomal abnormalities. Although encouraging, extrapolation of these results to other centers is not recommended without independent verification.

Cephalic index: a gestational age-dependent biometric parameter.

Cephalic index was proposed originally as a means of recognizing altered head shape and confirming the validity of biparietal diameter (BPD) measurements. Two previous studies found cephalic index to be gestational age-independent. We tested this relationship by regression analysis in 777 well-dated pregnancies, evenly distributed between 14-40 weeks' gestation. Significant variation in cephalic index was found with advancing gestational age, with the highest and lowest values observed at 14 and 28 weeks, respectively. Based upon application in a separate test population of 1361 normal fetuses, a threshold of +/- 1 SD maximized identification of misleading BPDs due to altered head shape.

Prenatal prediction of lethal pulmonary hypoplasia using ultrasonic fetal chest circumference.

Ultrasonic measurement of fetal chest circumference was tested as a predictor of pulmonary hypoplasia in a group of 26 fetuses at known risk. A 42% prevalence of autopsy-proved pulmonary hypoplasia was found in this population. Chest circumference measurements were plotted on published nomograms based upon head circumference, femur length, and gestational age. Longitudinal observations revealed a progressive lag in chest circumference growth among fetuses who proved to have pulmonary hypoplasia. The nomogram based on femur length provided sensitivity, specificity, and normal and abnormal predictive values of 80, 92, 92, and 89%, respectively. The results of this investigation suggest that fetal chest circumference measurement is a useful adjunct in establishing the diagnosis of lethal pulmonary hypoplasia.