Perinatal management of gastroschisis.

Fetal anterior abdominal wall defects will be recognized with increasing frequency with the widespread use of maternal serum alpha-fetoprotein screening. A clear distinction must be made between omphalocele and gastroschisis, and counseling and obstetric management must be specific for each. Sixteen cases of gastroschisis were identified antepartum and followed through delivery between 1980-1986. There was one antepartum fetal death before institution of a protocol to deliver all such affected fetuses at 36 weeks. One patient was lost to follow-up. There were no antenatal or neonatal deaths among the 14 infants seen subsequently, all of whom were delivered by cesarean section. Only one infant had an additional nongastrointestinal defect (mild hearing loss), and all 14 were of appropriate weight for gestational age. Twelve infants had a single operative procedure for repair of the defect, with a mean hospital stay of 19.6 days. Scheduled cesarean delivery at 36 weeks, after confirmation of fetal lung maturity, presents the infant to the pediatric surgeon under controlled conditions and shortens neonatal hospital stay.

Choroid plexus cysts in fetuses with trisomy 18.

An association between fetal choroid plexus cysts and trisomy 18 has been suggested. However, the prevalence of such cysts in aneuploid fetuses is unknown. To determine this frequency, we studied 14 fetuses with trisomy 18 examined at the Central Laboratory for Human Embryology. Five fetuses were found to have choroid plexus cysts on postmortem ultrasound examination. All those with cysts were earlier than 26 weeks in gestation, and the prevalence among second-trimester fetuses was 71.4%. In contrast, such cysts are reported in less than 1% of the general population of second-trimester fetuses. Thus, choroid plexus cysts are common in trisomy 18, and the finding of such cysts on a second-trimester ultrasound examination should suggest further evaluation, including chromosome analysis.

Exencephaly--clinical and ultrasonic correlation to anencephaly.

The antenatal sonographic diagnosis of exencephaly in four gestations is reported. Exencephaly is an uncommon malformation of the cranium that characteristically involves a large, disorganized mass of cerebral tissue. The flat bones of the calvaria are absent, leaving the brain mass uncovered. Secondarily, anencephaly may develop as a result of prolonged exposure of the developing encephalon to amniotic fluid and trauma in utero. As in anencephaly, facial structures and the bony base of the calvarium are often preserved in exencephaly. Sonographically, the outstanding feature of exencephaly is the cerebral mass, with convolutions or "pseudo" sulcal patterns present. These findings correlate well with the pathologic examination and define a clinical entity that is incompatible with human life.

Intraperitoneal fetal transfusion under direct ultrasound guidance.

The outcomes of 77 fetal intraperitoneal transfusions in 35 pregnancies managed with direct ultrasound guidance and intensive perinatal management were reviewed. Patients were monitored with amniocentesis, and standard indications were used for timing of transfusions. The mean gestational age at first transfusion was 27.3 weeks (range 22-33). The overall mortality rate was 14% (five of 35). No immediate transfusion-related deaths occurred; all fetuses who were not hydropic at first transfusion survived (26 of 26). The mean gestational age at delivery was 33.6 weeks (range 25-36). One infant developed respiratory distress syndrome (RDS). Transfusion-related complications occurred in five cases (fetal colon infusions in two, fetal retroperitoneal infusion in two, and fetal abdominal wall hematoma in one). None of these infants required urgent delivery or suffered long-term sequelae. In nonhydropic fetuses, intraperitoneal transfusions under direct ultrasound guidance had a low incidence of morbidity and no mortality. These results should provide baseline data against which to compare new techniques, such as direct cord transfusion. With neonatal mortality rates of 10% and significant morbidity rates of 10-20% in infants delivered at 32 weeks who develop RDS, intraperitoneal transfusion should be considered in the 32- to 33-week fetus with marked pulmonary immaturity.

Hydrops from reciprocating atrioventricular tachycardia in a 27-week fetus requiring quinidine for conversion.

A 27-week fetus with severe nonimmune hydrops was found to have a reciprocating atrioventricular tachycardia with the rate of 275 beats per minute. Maternal digitalization produced improvement without conversion. Large doses of propranolol were without effect. Twelve days later quinidine was added, and conversion to sinus rhythm occurred after only two hours and persisted to term. The infant has no heart disease. Literature review confirms digoxin as the first choice for treatment of fetal reciprocating tachycardia, with excellent transplacental passage. Propranolol has not been demonstrably effective, and has poor placental passage. Verapamil also produced poor cord blood levels in two trials. Placental passage for procainamide is uncertain, but long-term use has been unsatisfactory. Quinidine is recommended as the second drug for treatment of resistant fetal tachyrhythmias.

Genetic amniocentesis: significance of intraamniotic bleeding and placental location.

Simultaneous ultrasound was used to determine if there was a correlation between visualized intraamniotic bleeding, placental location, and fetal-maternal hemorrhage. It was hoped to then determine which Rh-negative patients should receive Rh immunoglobulin. Visualized intraamniotic bleeding showed no correlation to fetal-maternal hemorrhage. Intraamniotic bleeding was commonly associated with needle insertion through an anterior placenta, but also occurred regardless of placental location and in the absence of placental needle traversal. No correlation was found between placental location and fetal-maternal hemorrhage as evidenced by evaluation of maternal serum alpha-fetoprotein. The Kleihauer test was not as sensitive as alpha-fetoprotein.

The fetal genitourinary tract.

Early recognition of fetal urinary tract anomalies may dramatically influence obstetric or neonatal management. Major fetal urinary abnormalities, including renal agenesis, obstructive lesions, and cystic disease, may be clinically silent but readily identified by sonography. Careful evaluation of the fetal genitourinary tract should therefore be an important component of the routine screening obstetric sonogram. Appreciation of normal sonographic appearances of the fetal genitourinary tract may facilitate early recognition of the abnormal fetus. Accurate prenatal sonographic characterization of a renal abnormality and evaluation of renal function are essential for fetal prognosis and management.

Three-dimensional ultrasonic angiography using power-mode Doppler.

To visualize the vascular anatomy of parenchymal organs, we have developed a system for producing three-dimensional ultrasonic angiograms (3D USA) from a series of two-dimensional power-mode Doppler ultrasound (PDU) scans. PDU scans were acquired using a commercial scanner and image-registration hardware. Two-dimensional images were digitized, and specially designed software reconstructed 3D volumes and displayed volume-rendered images. The geometric accuracy of our system was assessed by scanning a flow phantom constructed from tubing. The system was tested on patients by scanning native and transplanted kidneys, and placentas. Three-dimensional images of the phantoms depicted the spatial relationships between flow within the tubing segments and contained less than 1 mm of geometric distortion. Three-dimensional images of the kidney and placenta demonstrated that spatial relationships between vasculature structures could be visualized with 3D USA. Applications of this new technique include analysis of vascular anatomy and the potential assessment of organ perfusion.

Automatic fetal head measurements from sonographic images.

RATIONALE AND OBJECTIVES: We designed an image processing technique to automatically measure the biparietal diameter (BPD) and head circumference (HC) from prenatal sonograms. We evaluated the performance of the algorithm by comparing the resulting measurements with those made by experienced sonographers. METHODS: Thirty-five digitized sonograms of the fetal head were obtained during routine imaging. The BPD and HC were automatically computed by detecting the inner and outer boundaries of the fetal skull using the computer vision technique known as the "active contour model." Six experienced sonographers also measured the BPD and HC on these images. RESULTS: The algorithm failed to locate the boundaries in two of the 35 cases. For the remaining cases, the mean absolute difference between the automated measurements and the average of the six observers was 1.4% for BPD and 2.9% for HC. The correlations were .999 for the BPD and .994 for the HC. The computer's measurements were no different from the six observers' measurements than the observers' measurements were from one another. CONCLUSION: The tested algorithm effectively and accurately measures BPD and HC automatically. We are currently in the process of integrating this algorithm into an ultrasound machine.

Twin growth problems: causes and sonographic analysis.

Understanding the significant increased risks associated with twin pregnancies requires knowledge of the embryogenesis of twins and the unique placental characteristics seen only in twin gestations. Dizygotic "fraternal" twins, 70% of all twins, are at relatively low risk when compared with monozygotic twins, largely due to abnormalities seen in association with monochorionic placentation. The sonographic determination of chorionicity and amnionicity allows better estimation of pregnancy risk--up to 50% mortality in monochorionic-monoamniotic twins. Careful evaluation of intrauterine twin growth assists in the early identification of fetal abnormalities because normal twin growth should parallel that of singleton pregnancies until late in the third trimester. A number of the unique complications affecting growth in twin pregnancies are discussed, including twin transfusion syndrome, the "stuck twin" phenomenon, twin embolization syndrome, and development of acardiac twins.

Severe nonimmune fetal hydrops with fetal survival. A case report.

A case of severe idiopathic nonimmune fetal hydrops spontaneously resolved after delivery with only basic supportive therapy. This case emphasizes that natural occurrences occasionally are responsible for successes attributed to invasive intrauterine treatments.

Proteins in the roots of the perennial weeds chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale Weber) are associated with overwintering.

Roots are the overwintering structures of herbaceous perennial weeds growing in temperate climates. During the fall they accumulated reserves which are remobilized when growth resumes in the spring. An 18kDa (kilodalton) protein increases in both chicory and dandelion roots during the fall months. The proteins in both species are antigenically similar, and are recognized also by an antibody to a storage-protein deposited in Jerusalem artichoke (Helianthus tuberosus) tubers. In chicory, the protein is root-specific, but in dandelion it is detectable in the flowers, vestigial stem and the seed. Electrophoretic characterization of the 18-kDa protein shows that it is a single polypeptide, without subunits, with charge isomers of pI values close to pH 6.5. The major protein present in chicory and dandelion roots is unlike the vegetative storage proteins recently found in soybean or the storage proteins in the bark of trees.

Prenatal diagnosis of agenesis of the corpus callosum.

The prenatal sonographic findings in seven cases of agenesis of the corpus callosum (AGCC) are reported. Findings that suggest AGCC on standard transverse views of the fetal cranium are emphasized. All seven cases demonstrated ventricular abnormalities including four fetuses (57%) who demonstrated laterally displaced lateral ventricles and/or disproportionate enlargement of the occipital horns. Two additional fetuses demonstrated a large midline fluid collection, representing a dilated third ventricle. The remaining case demonstrated atypical findings of a septated periventricular cystic mass. Following birth, additional malformations were found in 5 of the 7 fetuses (71%), including one fetus with trisomy 8. We conclude that AGCC can be suggested on the basis of prenatal sonographic findings and that awareness of typical findings should permit more frequent detection of this anomaly in utero. Due to the frequency of concurrent anomalies, identification of AGCC should initiate a careful search for additional malformations.

Fetal Doppler echocardiography in pulmonary atresia.

The prenatal diagnosis of pulmonary atresia is of particular importance because the affected neonate may be dependent on ductal blood flow to the lung, requiring urgent administration of prostaglandins. We review eight cases studied by ultrasonography in utero. Severe tricuspid regurgitation was present in six fetuses. Right ventricular size varied among cases. Right atrial enlargement was present in seven, usually with tricuspid regurgitation. Failure to identify the main pulmonary artery or valve on a single examination was not specific. Doppler flow studies were most reliable for the diagnosis by establishing the existence of retrograde flow in the ductus arteriosus from the aorta.

Disparity of amniotic fluid volume and fetal size: problem of the stuck twin--US studies.

The "stuck twin" phenomenon in monochorionic diamniotic (MCDA) pregnancies is characterized by marked disparity in both fluid volume and fetal size between the twin gestations. To determine the prevalence, sonographic characteristics, and clinical outcome of this phenomenon, discharge summaries, placental pathologic reports, and prenatal sonograms from 307 twin pregnancies were reviewed. Of 52 cases of MCDA pregnancies, 18 (35%) demonstrated marked disparity in amniotic fluid volume. In 16 of these 18 cases there was discordant twin growth, further suggesting the diagnosis of twin transfusion syndrome. All 16 cases and an additional nine cases supplied by another center demonstrated a small, morphologically normal fetus in an oligohydramniotic sac suspended anteriorly (72%) or laterally (28%) in the uterus. The amniotic membrane separating this twin from the larger twin in the polyhydramniotic sac was thin, closely applied to the smaller fetus, and difficult to detect. Perinatal morbidity was 100% for all twin pairs, and premature labor occurred in all cases. Perinatal mortality ranged from 88% for the larger/poly twin to 96% for the small/oligo twin.

Accumulation of free amino acids in the shoots and roots of three northern conifers during drought.

The effects of drought on the free amino acid pools in 21- to 23-week-old seedlings of black spruce (Picea mariana (Mill.) Britt.), white spruce (Picea glauca (Moench.) Voss) and jack pine (Pinus banksiana Lamb.) were followed during soil drying. Although water and pressure potentials were sensitive to water deficits, large changes in osmotic potential were not recorded until after the development of severe drought. Total soluble amino nitrogen in the shoots and roots of the three species rose as turgor declined, with peak concentrations attained late in the drought period when the pressure potentials of the shoots approached zero. All white spruce seedlings were alive at zero turgor and showed large decrements in osmotic potential, but concentrations of free amino nitrogen in the roots and shoots showed only modest increases, reaching 125 to 150% of their control values. In contrast, large numbers of black spruce and jack pine were dead or severely damaged at zero turgor, and only small changes in osmotic potential were detected during soil drying. Nevertheless, concentrations of soluble amino nitrogen in both species reached 150 to 200% of control values a few days before the seedlings died. Alanine, arginine, aspartic acid/asparagine, glutamic acid/glutamine, glycine, hydroxyproline and proline were the major components of the free amino acid pools under both water-stressed and non-stressed conditions, with the largest and most consistent increases observed in the roots of all three conifers. Although proline was an important and dynamic component of the free pools, absolute concentrations were commony equalled or exceeded by other free amino acids in the roots and shoots and nearly always exceeded by the concentration of aspartic acid/asparagine in both tissues. Differences in drought resistance among the three conifers were not reflected by unique patterns of amino acid accumulation or by large differences in absolute concentrations of the free amino acid pools.

Fetal bowel. Normal sonographic findings.

The normal sonographic appearance of fetal colon and small bowel is reported in a prospective study of 130 fetuses. The colon, which appeared as a continuous tubular structure located around the perimeter of the abdominal cavity, was seen in some fetuses as early as 22 menstrual weeks and in all fetuses examined after 28 weeks. Colon diameter demonstrated a linear relation (r = 0.82) with menstrual age, reaching a maximum of 18 mm at term. In comparison, small bowel was located centrally and individual segments never exceeded 7 mm in diameter or 15 mm in length. Small bowel loops were seen in only 30% of fetuses examined after 34 weeks. Peristalsis was routinely demonstrated of the small bowel, but was not observed in the colon.

A systematic approach to fetal echocardiography using real-time/two-dimensional sonography.

Improvements in the resolution of real-time scanners have facilitated examination of the fetal heart and the performance of fetal echocardiograms. The techniques for systematic examination have rarely been described in detail. Six echocardiographic views, described in this report, allow complete examination of the four cardiac chambers, as well as the valvular structures. Interatrial and interventricular septa may be visualized, as well as the great vessels.

Rate-based management of fetal supraventricular tachycardia.

We reviewed the ultrasonographic studies and the clinical course of 22 fetuses with supraventricular tachycardia to determine whether the heart rate alone could serve as a basis for conservative management. Hydrops was not encountered with heart rates under 230 beats per minute. The conditions of all 22 fetuses stabilized without invasive administration of medications. Eighteen were delivered vaginally and only four by cesarean section. No fetal or neonatal losses occurred. Regardless of the type of supraventricular tachycardia, reducing heart rate in these fetuses to levels preventing or resolving hydrops allowed term vaginal delivery, thereby reducing the substantial problems of ventilating an immature or hydropic neonate.

Efficacy of thromboresistant umbilical artery catheters in reducing aortic thrombosis and related complications.

Previous in vitro and in vivo reports suggest that catheters constructed of polyurethane with heparin bonded to the surface (HB-PU) are less thrombogenic than catheters made of polyvinyl chloride (PVC). A randomized trial sufficiently large (power 80%) to detect a reduction in the incidence of umbilical artery (UA) catheter complications, including aortic thrombus formation, from 45% to 20% was conducted in 125 infants. The infants were monitored for complications possibly related to the use of a UA catheter, such as systemic hypertension and abnormalities of lower extremity perfusion. The presence of aortic thrombi was assessed by ultrasound study 3.5 +/- 1.2 (SD) days and 11.1 +/- 2.3 days after insertion of the catheter. The use of HB-PU umbilical catheters did not lead to a significant reduction in the incidence of complications and aortic thrombi compared with the use of PVC catheters. The lack of reduction may have been related to the prolonged duration of catheter use in both groups. A much larger study would have been required to detect a smaller, but perhaps clinically significant, reduction in catheter-associated complications.