Marge Tortora

Orbital diameters: a new parameter for prenatal diagnosis and dating.

Fetal inner orbital diameter and outer orbital diameter were measured in the occipital transverse and occipital posterior positions in 180 normal pregnancies. The outer orbital diameter was found to be closely related to the biparietal diameter. After a nomogram had been constructed, 463 patients whose fetuses were at risk for various anomalies were studied in two cases, hypotelorism was suspected because the orbital measurements fell below the 95% confidence limits, and this diagnosis was confirmed at the time of delivery. The conclusion is that, in situations in which fetal head position precludes accurate biparietal diameter determinations, the outer orbital diameter can often be obtained and used to estimate that variable and, therefore, gestational age. Furthermore, the nomogram constructed has proved to be a useful tool in diagnosing hypotension in utero. Theoretically, this should also be true of fetal hypertelorism.

The diagnosis of fetal hydrocephalus

Thirty cases of fetal hydrocephalus were diagnosed at the perinatal ultrasound unit of Yale-New Haven Medical Center during a 41 month period. Prenatal ultrasound was found to be highly valuable in the detection of fetal hydrocephalus. However, the antenatal detection of associated anomalies was not as uniformly successful. The importance of a complete sonographic evaluation of intracranial and extracranial anatomy is stressed, as 10 patients with documented hydrocephalus (37%) had associated intracranial anomalies and 17 patients (63%) had associated extracranial anomalies. In this series, isolated hydrocephalus without associated anomalies occurred in only four patients (15%).

Dilation of the fetal umbilical vein in rhesus hemolytic anemia: A predictor of severe disease

Presented in part at the annual meeting of the American Institute of Ultrasound in Medicine, September, 1980, New Orleans, Louisiana. Reprint requests: Greggory R. DeVore, M.D., Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Southern California, LAClUSC Women’s Hospital, 1240 North Mission Road, Los Angeles, California 90033. fourth week of gestation, the bone marrow begins to produce hematopoietic cells, and the liver and spleen concomitantly decrease their production.’ When Rh antibody-mediated hemolytic anemia develops, however, the fetal liver increases its erythropoietic activity and enlarges. This is associated with decreased synthesis of serum albumin, with resultant low osmotic pressure.z When this is severe, fluid accumulates in the extravascular compartments, and fetal hydrops results. Although the delta optical density (AOD) of amniotic fluid bilirubin at 450 rnp is used to discover those fetuses with severe hemolytic disease in whom intrauterine transfusion (IUT) is mandatory, serial diagnostic ultrasound is a useful adjuvant in the evaluation of fetal well-being. Presented here are the results of a study designed to evaluate, by means of ultrasound, fetal hepatic congestion resulting from increased erythropoiesis in Rh-sensitized pregnancies. The fetal umbilical vein diameter (UVD) in the-amniotic fluid (AF) and the liver (L) were measured from images obtained with a contact B and a realtime linear array scanner (Fig. 1). In a cross-sectional evaluation of 94 normal control fetuses, the UVD in the AF progressively increased from week 18 through week 30 of ges-

Stage II ultrasound examination for the diagnosis of fetal abnormalities with an elevated amniotic fluid alpha-fetoprotein concentration.

Previous studies have indicated that patients with elevated levels of amniotic fluid alpha-fetoprotein (AFAFP) are at very high risk for fetal neural tube defects. Twenty-eight patients whose levels of AFAFP were greater than 3 standard deviations above the mean were evaluated with a Stage II ultrasound examination for detailed assessment of fetal anatomy. In 16 patients with AFAFP levels greater than 5 SD above the mean, six fetuses with open spina bifida were identified (37.5%). Moreover, in four fetuses in this group, the diagnosis was ventral wall defects (two with gastroschisis and two with omphalocele), and one fetus had multiple lethal anomalies. The other 5 patients had normal scans, and, with the exception of one patient who was delivered of a nondysmorphic stillborn infant at 28 weeks, all had normal infants at birth. Among the other 12 patients with AFAFP levels between 3 and 5 SD above the mean, there were only two adverse findings--an intrauterine death and an omphalocele. A Stage II ultrasound examination performed when AFAFP levels are elevated enables one to distinguish between conditions which are lethal or associated with significant impairment and those which are amenable to surgical procedures. Morphologically normal fetuses can also be identified. Since this diagnostic technique will allow salvage of many pregnancies that otherwise would be aborted, it should be an integral part of any alpha-fetoprotein screening program.