Faculty Bibliography

The evolution of the sonographic diagnosis of placenta previa is reviewed with special emphasis on transvaginal sonography (TVS), which has been proved accurate at diagnosing different degrees of placenta previa, such as complete, partial, marginal and low-lying. Bleeding tendency and the need for Caesarean delivery increases when the placental edge is within 3 cm of the internal os. There is no association between bleeding and use of transvaginal probes. The early diagnosis of addition abnormalities of implantation (e.g. placenta accreta) using transvaginal colour flow Doppler widens the prospects for carefully planned patient management. In conclusion, TVS should be the principal diagnostic modality used in the work-up of an obstetric patient with vaginal bleeding. The ease of performance and the clarity and accuracy of method and the additional information about implantation that it can provide will soon make TVS the 'golden standard' in the diagnostic process of placenta previa

This report contains the experience of our centre, using the transvaginally guided puncture procedure, to reduce the number of fetuses in a multifetal pregnancy to a lower number. The aim of the procedure was to improve perinatal outcome and/or to meet the personal desires of patients and their families. We surveyed 148 multifetal pregnancy reductions. The fetus or fetuses overlying the internal os was most commonly reduced. The total uncorrected loss of the entire pregnancy was 13.4%. The corrected pregnancy loss was 11%. Of the 63 twins left after the reduction, 33 delivered preterm. Of the 36 singletons, two delivered preterm. Our conclusion was that multifetal pregnancy reduction is a safe procedure for the mother and has an acceptable loss rate of the entire pregnancy. The reduction of a fetus overlying the internal os by the transvaginal puncture procedure seems to yield results at least as good as the transabdominally performed puncture procedures for multifetal pregnancy reduction

Fetal upper respiratory tract function was studied in five cases of antenatally diagnosed congenital diaphragmatic hernia and in 16 cases of uncomplicated pregnancy at gestational ages ranging from 27 to 38 weeks. The evaluation of fetal upper respiratory tract function was performed using ultrasonography combined with color-flow and spectral Doppler analysis. In all cases with uncomplicated pregnancy, fetal breathing-related nasal and oropharyngeal fluid flow was seen at the level of the nose. The five cases with congenital diaphragmatic hernia all demonstrated fetal breathing activity by thoracic wall movement. In four of the fetuses, perinasal fluid flow was seen by the Doppler technique. The fetus with no demonstrated perinasal flow during breathing movements died in the early neonatal period and had pulmonary hypoplasia. Observation of the fetal breathing-related nasal and oropharyngeal fluid flow in cases of antenatally diagnosed congenital diaphragmatic hernia provides a rationale to hypothesize that the absence of this phenomenon is a useful marker for prenatal prediction of pulmonary hypoplasia

Nomograms of the fetal lateral ventricles were obtained by the transvaginal approach. Three hundred low-risk women with no sonographically apparent fetal anomalies were scanned prospectively in a cross-sectional study. Three measurements in the parasagittal plane, three in the midline coronal plane, and two in the posterior coronal plane were used to generate seven nomograms. Two additional nomograms reflecting two calculated ratios also were created. A mean regression line and the 5th and 95th confidence intervals were determined. We concluded that transvaginal sonography of the fetal brain generates images of both hemispheres of good enough resolution to allow several precise and reproducible measurements

OBJECTIVE: To evaluate the safety of transvaginal ultrasonography in the diagnosis of placenta previa by determining whether the angle between the cervix and the vaginal probe is sufficient for alignment of the probe with the cervix. METHODS: The angle between the axis of the cervix and that of the vaginal probe (the axis of the vagina) was measured from copies of the transvaginal ultrasound examinations of 18 patients with documented placenta previa past 20 weeks' gestation. The measurements were compared with those of gestationally matched controls without placenta previa. RESULTS: The mean angles were 63.8 degrees and 67.5 degrees, with minimum angles of 44 degrees and 48 degrees for the placenta previa and control groups, respectively. The values were not statistically different. CONCLUSION: These findings strengthen the previously undocumented presumption that the angle between the cervix and vaginal probe is sufficient to prevent the probe from inadvertently slipping into the cervix. Therefore, this study supports the safety of transvaginal sonography in diagnosing and monitoring patients with known placenta previa

First-trimester fetal biometry using transvaginal sonography is now feasible and desirable due to improved imaging and probe maneuverability. A study of 144 early normal pregnancies with precise dates is presented. Regression models were constructed for the crown-rump length, biparietal diameter, head circumference and abdominal circumference. Error analysis of the technique and calculations was performed. First-trimester fetal biometry may be used for obtaining precise estimates of gestational age and may help to detect early fetal maldevelopment resulting in abnormal growth

OBJECTIVE: This report reviews multifetal pregnancy reductions performed transvaginally and tests the feasibility and associated pregnancy loss rates with this technique. STUDY DESIGN: One hundred thirty-four consecutive multifetal pregnancy reductions were analyzed regarding different aspects of total pregnancy losses and complications. The first 40 manually performed were compared with the last 94 procedures performed with an automated puncture device and a thin needle. The losses were also analyzed as a comparison of the reduction of the lower-lying with the higher-lying fetuses located in relation to the internal os. RESULTS: A total uncorrected total pregnancy loss rate of 12.6% and a corrected loss rate of 10.6% was observed. Of the 112 pregnancies in which the lower-lying fetus was reduced, 11 losses were seen. The loss rate in the group reducing the upper fetus was three of 22. The manual versus the puncture device groups showed the same loss rate (10%); however, the manual group had a larger number of subchorionic hematomas after the procedure. CONCLUSIONS: The data are indicative of a very low maternal complication rate (infection) and an acceptable loss rate of the entire pregnancy. The loss rates compare favorable with those for multifetal pregnancy reduction performed transabdominally

Transabdominal use of a software integrated, automated, spring-loaded transvaginal puncture device is described. This device allows accurate, high-velocity needle placement into sonographically targeted areas under continuous direct vision without the use of local anesthesia. Successful use of the device in seven cases is described

We hypothesized that because fetal stomach filling and emptying is a dynamic process, measurements of the stomach dimensions might not be reproducible. Serial measurements 20 minutes apart were made of the stomach in 146 fetuses at 14 to 41 weeks of gestation. In 88 of these fetuses, the biparietal diameter also was measured to provide a standard for comparison. The mean percentage change between each of the paired measurements was 16.6% to 43.1% for the different stomach dimensions, compared with only 2% for the biparietal diameter (P < 0.001). We suggest that caution be excised in the diagnostic use of stomach measurements owing to their dynamically changing nature