Joseph B. Landwehr

Limited usefulness of fetal weight in predicting neonatal brachial plexus injury

OBJECTIVE The objectives were to determine the neonatal morbidity rate from vaginal birth and examine fetal weight-based injury-prevention strategies. STUDY DESIGN Selected neonatal morbidities were categorized by birth weight for all vertex vaginal deliveries occurring during a 12-year period. Sensitivity, specificity, and predictive values for brachial palsy were calculated at increasing birth weight cutoff levels. A policy of cesarean delivery for macrosomic infants was evaluated. RESULTS There were 80 cases of brachial palsy among 63,761 infants (0.13%). In mothers without diabetes, rates in the 4500- to 4999-g and >5000-g groups were 3.0% and 6.7%, respectively. A threshold of 3700 g had a sensitivity of 71% and a specificity of 86%; the positive predictive value was 0.56%. To prevent a single case of permanent injury, 155 to 588 cesarean deliveries are required at the currently recommended cutoff weight of 4500 g. CONCLUSIONS The rates of lasting morbidity do not justify routine cesarean delivery for infants without diabetic complications weighing <5000 g.

Telemedicine and fetal ultrasonography: Assessment of technical performance and clinical feasibility

OBJECTIVE Our aim was to determine the performance and clinical feasibility of telesonography for the interpretation of fetal anatomic scans sent from a remote location compared with those obtained at a tertiary care prenatal ultrasonography center. STUDY DESIGN Routine ultrasonographic studies from 35 patients were remotely interpreted. Evaluation included a blinded comparison of the sonographers assessment of 38 fetal structures with that of the physician at the tertiary care center. Technical evaluation included system reliability and the number of digital telephone lines required for adequate real-time visualization. RESULTS The mean gestational age at the time of the ultrasonography was 25.84 +/- 6.8 weeks (range 14 to 38). There was complete consistency of interpretation for 25 of 38 (66%) fetal structures. Thirteen structures had discrepancies in visualization, reflecting a difference in the adequacy of visualization, not the normalcy or identity of the structures. Three digital (integrated switching digital network, ISDN) telephone lines were required for real-time visualization. CONCLUSION Our preliminary experience supports telesonography as a clinically useful tool for remote interpretation of fetal ultrasonographic examinations. Further studies are warranted for the continued evaluation of this emerging technology.

The Apparently Isolated Choroid Plexus Cyst: Importance of Minor Abnormalities in Predicting the Risk for Aneuploidy

Objectives: To assess the risk of aneuploidy in cases of isolated choroid plexus cysts (CPCs) and to compare the risk when associated with minor or major anomalies. Methods: All fetuses with CPCs and known karyotype were identified. CPCs were categorized as ‘isolated’ or associated with minor or major sonographic anomalies. Preexisting risk factors for aneuploidy were compared between groups. The frequency of aneuploidy was compared between fetuses with isolated CPCs and those with CPCs associated with minor or major anomalies. Continuous and categorical variables were analyzed using one-way analysis of variance or chi-square as appropriate with p < 0.05 considered significant. Results: One hundred and forty-nine fetuses with CPCs diagnosed at a mean gestational age of 19 weeks were identified. No significant differences in the frequency of preexisting risk factors for aneuploidy were identified between groups. Eighteen of 149 (12%) fetuses with CPCs had other sonographic anomalies; in 10 they were minor, and 2 of the 10 had abnormal karyotypes. Four of 8 fetuses with major anomalies were aneuploid. All 131 fetuses with isolated CPCs had normal karyotypes, and all aneuploid fetuses had additional anomalies. Conclusions: The overall rate of aneuploidy in patients with CPCs was 4% with no abnormal karyotypes among isolated CPCs. The presence of even minor sonographic abnormalities substantially increased the risk of aneuploidy. Isolated CPCs identified sonographically may not place the patient at risk of aneuploidy, but should prompt a diligent search for other minor or major anomalies. The finding of any other anomaly warrants consideration for karyotypic evaluation.

Abnormal nuchal findings on screening ultrasonography : Aneuploidy stratification on the basis of ultrasonographic anomaly and gestational age at detection

OBJECTIVE Our purpose was to determine the specific likelihood of different aneuploidies by gestational age in patients with nuchal folds and simple and septated nuchal membranes. STUDY DESIGN Retrospective database analysis was performed of 158 consecutive patients with a nuchal fold or simple or septated nuchal membrane on either abdominal or vaginal ultrasonography. RESULTS Thirty-eight patients with nuchal folds, 65 with simple nuchal membranes, and 55 with septated nuchal membranes were evaluated. Septated nuchal membranes were associated with the highest incidence of karyotypic abnormalities (> 50%). A peak incidence of trisomy 21 (27%) was found in the early midtrimester, leveling off to 11% by the late midtrimester. The late first trimester had a high incidence of trisomy 18 (22%), occurring more frequently than 45,X. CONCLUSION Ultrasonographic anomalies in the posterior neck are associated with aneuploidy from 21% to 58% of the patients in this selected population. Each anomaly has different risks for aneuploidy type, varying with gestational age at diagnosis.

Limited clinical utility of midtrimester fetal morphometric percentile rankings in screening for birth weight abnormalities

OBJECTIVE Our purpose was to determine whether midtrimester fetal ultrasonographic morphometric percentile rankings are sensitive screening tests for preterm labor or birth weight abnormalities. STUDY DESIGN Stepwise multiple regression and chi 2 analysis were used to identify midtrimester fetal measurements predicting birth weight and gestational age. Receiver-operator characteristics curves were used to evaluate abdominal circumference percentiles as a test for large-for-gestational-age and small-for-gestational-age infants. RESULTS Extremes in abdominal circumference and head measurement percentiles were associated with large- and small-for gestational-age infants but not with preterm delivery. Abdominal circumference predicted birth weight in regression analysis; however, receiver-operator characteristic curves showed abdominal circumference percentiles to be poor screening tests for large- or small-for-gestational-age infants. The positive predictive value of 10th and 90th abdominal circumference percentiles for small- and large-for-gestational-age infants was < 20%. CONCLUSION Midtrimester percentile rankings offer no clear benefit in targeting fetuses with potential birth weight abnormalities or risk of preterm delivery and may provide clinically misleading information.

Book Review and Announcements

This excellent guide armed at assisting the pediatric house officer and neonatology fellow in day-to-day practice issues in neonatal intensive care is a second edition of the first one written in 1979. Each section was carefully updated and new and expanded sections have been added to take into account the changes in neonatal practice. New chapters include percutaneous central venous catheters, congenital epidermolysis bullosa, neonatal neoplasms, major vessel thrombosis, fetomaternal hemorrhage, fetal and neonatal arrhythmias, the effects of maternal drugs on the fetus/newborn and lactation, high-frequency ventilation, neonatal pain, the neonatal airway, neonatal anesthesia, and inhalational nitric oxide therapy. The role of the neonatal nurse practitioner is also addressed. The chapters on neonatal surgery and respiratory care have been expanded, as has the section on neonatal infection, which includes guidelines for intrapartum and neonatal management of group B streptococcal disease. Serge Uzan, Paris