Faculty Bibliography

OBJECTIVE:To compare the cost and benefits of prenatal diagnosis for Down syndrome using the British and American approaches. METHODS:This cost-benefit analysis was based on a decision-analytic approach. The British strategy included screening by a first-trimester ultrasound at 10-14 weeks for nuchal translucency thickness, and the American strategy included only second-trimester screening by using maternal age and maternal serum screening. The key probabilities of the decision-tree analysis and all cost estimates were based on American standards. The best scenario of the British strategy assumed ultrasound nuchal translucency thickness sensitivity (for detecting Down syndrome) of 80% and a false-positive rate of 5% and the worst scenario assumed a sensitivity of 50% and a false-positive rate of 10%. The results were expressed in annual costs based on approximately 4 million births per year in the United States. RESULTS:As compared with do-nothing, the American strategy was found to allow savings of approximately $96 million per year and the best scenario for the British strategy was savings of approximately $5 million per year. The financial costs of the British and American strategies would be comparable only if the first-trimester ultrasound had a sensitivity of 80% and a false-positive rate of 5% in detecting Down syndrome. CONCLUSION/CONCLUSIONS:The British strategy does not appear to be economically beneficial in the United States even under the most ideal scenarios of ultrasound accuracy.

Sonographic fetal foot length is highly predictive of gestational age. In order to assess the reliability of this parameter in predicting gestational age in cases of abnormal fetal growth, we examined fetal foot length in small- and large-for-gestational-age fetuses. A nomogram of foot length versus gestational age between 15 and 37 weeks was constructed using cross-sectional data obtained from 5372 singleton fetuses. Fetal foot lengths for small-for-gestational-age fetuses (estimated fetal weight below the 10th percentile) and large-for-gestational-age fetuses (above the >90th percentile) fetuses were plotted against the foot length nomogram in order to determine the number of small-for-gestational-age fetuses and large-for-gestational-age fetuses with foot lengths below the 10th and above the 90th percentiles, respectively. Of the 586 small-for-gestational-age fetuses, 355 (60.6%) had foot lengths below the 10th percentile on the nomogram. When foot lengths from large-for-gestational-age fetuses were plotted on the foot length nomogram, 29.4% (219 of 744) had measurements above the 90th percentile. Fetal foot length can be influenced by growth restriction as well as states of accelerated fetal growth. Our findings imply that there are limitations to the use of fetal foot length for gestational age assessment, particularly in fetuses with growth abnormalities

OBJECTIVE:The objective of this study was to perform a cost-benefit analysis of routine second-trimester screening ultrasonography in the United States as compared with performing ultrasonography only in the presence of indications. STUDY DESIGN/METHODS:It was assumed that 1 million pregnant women are available annually who otherwise would not have an indication for an ultrasonographic examination. Cost savings from early detection and therapeutic abortion were considered only for fetal conditions for which lifetime cost estimates are available, including spina bifida, major cardiac disease, cleft lip or palate, renal agenesis or dysgenesis, urinary obstruction, lower or upper limb reduction, omphalocele, gastroschisis, and diaphragmatic hernia. Two separate cost-benefit analyses were considered with the range of fetal anomaly detection rates before 24 weeks' gestation as reported by tertiary and non-tertiary centers in the Routine Antenatal Diagnostic Imaging with Ultrasound (RADIUS) trial. Potential cost savings from averting treatment for preterm labor and postdate gestations were also considered. RESULTS:The ratio of savings to cost was between 1.35 and 1.70 (savings of $1.35-$1.70 per $1 spent) if the ultrasonographic examinations were performed in tertiary care centers. The ratio of savings to cost was between 0.40 and 0.74 (loss of $0.26-$0.60 per $1 spent) if the examinations were performed in nontertiary centers. If the screening ultrasonography was performed in tertiary centers, the expected annual net benefits were estimated at $97 to 189 million. If ultrasonographic screening was performed in nontertiary centers, the expected annual net losses were estimated at $69 to 161 million. CONCLUSION/CONCLUSIONS:Routine second-trimester ultrasonographic screening appears to be associated with net benefits only if the ultrasonography is performed in tertiary care centers.

One of the most important advances in perinatal health care is the use of antepartum fetal testing. Antepartum fetal testing methods may include inexpensive tests such as fetal kick counts or tests that can be quite expensive such as non-stress tests, fetal biophysical profiles, and Doppler assessments as well as invasive tests such as amniocentesis or cordocentesis. Clinical experience, combined with recent literature, suggest that there is no ideal test for all high-risk fetuses and that some antepartum fetal tests may be more appropriate than others, depending on the underlying pathophysiology or the indication for testing. Because many different pathophysiological processes lead to fetal acidemia and in-utero death, indication-specific testing may be not only logical, but also cost-effective. In this article, specific guidelines of antepartum fetal testing are presented. These indication-specific guidelines are based on the underlying pathophysiological processes that place the fetus at risk and also on the need to use the fewest number of tests without compromising safety.

OBJECTIVE:To estimate the rate of histologic chorioamnionitis in the presence of diagnosed clinical chorioamnionitis and determine whether clinical markers of maternal and neonatal infection are associated with histologic chorioamnionitis. METHODS:We identified singleton pregnancies from 1996 in which discharge diagnoses included clinical chorioamnionitis and reviewed maternal and neonatal records for clinical evidence of chorioamnionitis and suspected or confirmed neonatal infections. Placentas were examined for acute histologic chorioamnionitis. RESULTS:One hundred thirty-nine pregnancies with the discharge diagnosis of maternal clinical chorioamnionitis were included. Eighty-six (61.9%) had the clinical diagnosis supported by histologic chorioamnionitis. Histologic chorioamnionitis was associated with an earlier gestational age at delivery (35.7+/-6.5 weeks versus 38.6+/-2.9 weeks, P = .002), lower epidural usage (72.1% versus 92.5%, P = .004), less internal monitoring (47.7% versus 75.5%, P = .001), and possible neonatal sepsis (60.5% versus 35.8%, P = .005). For 19 of 71 (26.8%) infants with possible neonatal sepsis, placentas did not show histologic chorioamnionitis. CONCLUSION/CONCLUSIONS:Clinical chorioamnionitis and possible neonatal infection were not supported by histologic evidence for infection in 38.1% and 26.8% of cases, respectively, suggesting other noninflammatory causes of signs and symptoms.

OBJECTIVE: The object of this study was to determine whether there are any clinically significant indication-specific variations in the accuracy of second-trimester genetic ultrasonography and to provide a risk adjustment for fetal trisomy 21 according to the results of genetic ultrasonography. STUDY DESIGN: From November 1, 1992, to September 30, 1998, a second-trimester genetic sonogram was offered to all pregnant women who were at an increased risk for fetal trisomy 21 (>/=1:274) because of either advanced maternal age (>/=35 years) or abnormal serum biochemical profile or both of these. Outcome information included the results of genetic amniocentesis if performed and the results of pediatric assessment and follow-up after birth. In determining diagnostic accuracy of the genetic sonogram the presence of >/=1 abnormal ultrasonographic marker was considered an abnormal test result. RESULTS: A total of 1835 fetuses with known outcomes underwent genetic ultrasonography between 15 and 24 weeks' gestation; of these 1792 had normal results, 34 had trisomy 21, and 9 had other chromosomal abnormalities. The likelihood of fetal trisomy 21 was reduced by 80% after a normal result of genetic ultrasonography. The overall sensitivity, specificity, and positive and negative predictive values of genetic ultrasonography for the detection of trisomy 21 were 82%, 91%, 15%, and 99.6%, respectively. There were no significant indication-specific variations in the accuracy of second-trimester ultrasonography. The sensitivity for the detection of fetal trisomy 21 ranged from 80% among women with advanced maternal age to 100% among women with both an abnormal biochemical profile and advanced maternal age. CONCLUSIONS: The likelihood of fetal trisomy 21 risk was reduced 80% after a normal result of genetic ultrasonography. In addition there were no significant indication-specific variations in the detection rate of genetic ultrasonography

OBJECTIVE:To compare the efficacy and cost effectiveness of different screening programs for fetal Down syndrome (DS). METHODS:Screening tools evaluated included maternal age, triple screening (TS), and ultrasound (U/S) for fetal markers of DS. Sensitivities used were TS: 55% <35 years, 80% > or = 35 years; U/S: 70%. Average regional fees used were TS: $80, U/S: $200, amniocentesis (AM): $1,000. Five screening programs were evaluated: 1) <35 years, no screening; > or = 35 years, AM; 2) <35 years, TS with AM for screen-positive subjects; > or = 35 years, AM; 3) all patients, TS with AM for screen-positive subjects; 4) <35 years, TS followed by U/S for screen-positive women, AM for women with fetal markers of DS on U/S; > or = 35 years TS with AM for screen-positive subjects; 5) all women, TS followed by U/S for screen-positive women, AM for women with fetal markers of DS on U/S. The sensitivity, total cost, cost/case DS detected (Cost/DS), AM losses, and residual risk (RR, undetected DS fetuses/women not receiving AM) were calculated for each screening program. Population analysis was performed using 1988 IL delivery statistics. RESULTS:It was estimated that 260 cases of DS would occur in the population of 167,654 women (8.4% > or = 35 years at delivery). Sensitivity for programs 1-5 was 30, 69, 62, 51, and 36 percent, respectively, and cost/DS was 181,000, 203,000, 162,000, 151,000, and 194,000 dollars, respectively. CONCLUSIONS:DS screening incorporating TS in all patients with program #4 and without program #3 selective U/S in women <35 years yield the best combination of sensitivity and cost effectiveness while minimizing the number of AM-related losses.

OBJECTIVE:The purpose of this study was to compare the results of a standardized self-completed domestic abuse questionnaire with those of a directed interview in the identification of domestic abuse in pregnant patients. STUDY DESIGN/METHODS:All patients with a first prenatal visit between March 1 and September 30, 1997, were assessed for self-reported domestic abuse with a standardized domestic abuse questionnaire. This was followed by a directed interview that involved verbal review of the standardized domestic abuse questionnaire. Self-reported domestic abuse was defined as any positive response to the domestic abuse questionnaire or the directed interview. The number of patients with a positive response to either the standardized questionnaire or the directed interview, or both, were recorded. The 2 techniques were compared by the McNemar chi(2) test. The group demographics and characteristics were evaluated. RESULTS:Among the 224 patients evaluated, a total of 36% (n = 80) of the patients reported domestic abuse by either method. The standardized domestic abuse questionnaire identified 85% (n = 68) compared with 59% (n = 47) by a directed interview (P =.03). The use of the standardized domestic abuse questionnaire and the directed interview in parallel identified an additional 15% (n = 12) of patients with domestic abuse. CONCLUSION/CONCLUSIONS:A standardized domestic abuse questionnaire is superior to a directed interview in identifying self-reported domestic abuse in pregnancy. Utilizing both methods in parallel further increases the number of patients identified.

OBJECTIVE: Our objective was to determine whether there were any differences in the placental lesions of high-risk patients with versus without ultrasonographic evidence of cervical shortening between 15 and 24 weeks' gestation. STUDY DESIGN: Women who were at risk for pregnancy loss and spontaneous preterm birth were followed by serial transvaginal cervical ultrasonography with transfundal pressure between 15 and 24 weeks' gestation. Two groups of women were identified: those in whom progressive cervical shortening developed to below 2 cm, either spontaneously or induced by transfundal pressure, and those in whom it did not. A perinatal pathologist who was blinded to the pregnancy outcome retrospectively examined placental histologic slides. The histologic placental lesions were categorized as acute or chronic inflammatory lesions, decidual vascular lesions, and coagulation-related lesions. RESULTS: There were 278 women who were followed during the study. Placentas were submitted for histologic examination in 189 cases (125 singleton, 45 twin, and 19 triplet gestations). There were 72 pregnancies with and 117 pregnancies without an ultrasonographic diagnosis of cervical shortening, respectively. Overall, there were significantly more acute inflammatory lesions in patients in whom cervical shortening developed, as determined by ultrasonographic examination. However, there were significantly more decidual vascular lesions in women in whom cervical shortening did not develop. When we examined the distribution of the placental histologic lesions in the 64 cases of multiple gestations, the only significant finding was again a greater frequency of acute inflammatory lesions in patients in whom cervical shortening developed. There was no difference in the distribution of the placental histologic lesion categories among women treated with bed rest versus cervical cerclage because of the ultrasound diagnosis of cervical shortening. CONCLUSION: Acute inflammatory lesions of the placenta were more frequent in patients with second-trimester cervical shortening. These findings support that patients with cervical shortening in the second trimester are prone to acute placental inflammation

OBJECTIVE:The objective of this study was to conduct an economic evaluation of routine prenatal carrier testing for fragile X syndrome. METHODS:This economic analysis was conducted from the societal perspective. A cost-benefit equation was developed based on the premise that the cost of routinely offering prenatal carrier testing for fragile X syndrome should be at least equal to, or less than, the cost of the current practice of not offering such testing. Sensitivity analyses included key assumptions regarding therapeutic abortion rates (50-100%) and patient screening acceptance rates (50-80%). RESULTS:A policy of routinely offering prenatal carrier testing for fragile X syndrome may be beneficial only if the cost per screening test is less than $120 during the first year of the screening program, or less than $240 when the program reaches its full maturity. Given the current cost per screening test of $250, prenatal screening for carrier status for fragile X syndrome carries the potential for annual losses of approximately $10 to $195 million in the United States. In addition, approximately 46-115 fetal lives may be lost due to invasive genetic procedures. CONCLUSIONS:Prenatal screening for fragile X syndrome may be economically beneficial only if the cost of the prenatal screening test for carrier identification is considerably less than the current cost.