Dru E. Carlson

Three-dimensional ultrasonography in obstetrics and gynecology: Preliminary experience☆☆☆★★★

OBJECTIVE Technologic advances in ultrasonographic imaging have revolutionized the management of womens health care. We recently began to evaluate the clinical applications of three-dimensional ultrasonography. STUDY DESIGN This study prospectively evaluated 161 obstetric and gynecologic patients. Both two- and three-dimensional imaging data were acquired from real-time ultrasonography. Three orthogonal planes were displayed on a monitor and were used to create the rendered three-dimensional images. RESULTS To date, 201 three-dimensional ultrasonographic studies have been performed, 165 transabdominally and 36 transvaginally. Transabdominally, an average of eight acquisitions per patient were obtained. Of the clinically suspected abnormalities, 29 of 32 (91%) were confirmed by three-dimensional imaging. Three of 32 (9%) improved the diagnostic capabilities or changed the diagnosis. Of the 36 transvaginal studies, an average of four acquisitions per patient were done. Thirty (83%) of these patients had suspected abnormalities and all were confirmed. CONCLUSIONS Three-dimensional ultrasonographic imaging appears to be highly promising in the clinical setting.

Prenatal diagnosis of human parvovirus B19 in nonimmune hydrops fetalis by polymerase chain reaction

OBJECTIVE Nonimmune hydrops fetalis is a potentially lethal condition reflecting the clinical manifestation of several pathologic processes. Recently maternal infection by human parvovirus B19 has been reported to result in nonimmune fetal hydrops. We sought to develop a rapid and sensitive test to detect the presence of this agent in utero. STUDY DESIGN Using a cloned isolate of the virus, we developed an assay based on enzymatic amplification of a segment of the human parvovirus B19 genome that allows direct detection of this agent in samples of fetal blood and amniotic fluid. RESULTS The method detected as few as 100,000 genome equivalences and was specific for the viral genome alone. We used this assay to evaluate nine fetuses initially seen with nonimmune hydrops. Three cases were found to be positive for the human parvovirus B19 genome. CONCLUSION The method is powerful in that it is rapid, sensitive, and simple. This assay may have general applicability in evaluation of nonimmune hydrops and in documentation of the natural history of fetal human parvovirus infections.

Mosaic trisomy 16 ascertained through amniocentesis: Evaluation of 11 new cases

Trisomy 16, once thought to result uniformly in early pregnancy loss, has been detected in chorionic villus samples (CVS) from on-going pregnancies and was initially ascribed to a second, nonviable pregnancy. Prenatally detected trisomy 16 in CVS and its resolution to disomy has led to the reexamination of the viability of trisomy 16. This study evaluates 11 cases of mosaic trisomy 16 detected through second trimester amniocentesis. In 9 of the 11 cases, amniocenteses were performed in women under the age of 35 because of abnormal levels of maternal serum alpha-fetoprotein (MSAFP) or maternal serum human chorionic gonadotropin (MShCG). The other two amniocenteses were performed for advanced maternal age. Five of the 11 pregnancies resulted in liveborn infants, and six pregnancies were electively terminated. The liveborn infants all had some combination of intrauterine growth retardation (IUGR), congenital heart defects (CHD), or minor anomalies. Two of them died neonatally because of complications of severe congenital heart defects. The three surviving children have variable growth retardation, developmental delay, congenital anomalies, and/or minor anomalies. In the terminated pregnancies, the four fetuses evaluated by ultrasound or autopsy demonstrated various congenital anomalies and/or IUGR. Cytogenetic and fluorescent in situ hybridization studies identified true mosaicism in 5 of 10 cases examined, although the abnormal cell line was never seen in more than 1% of cultured lymphocytes. Placental mosaicism was seen in all placentas examined and was associated with IUGR in four of seven cases. Maternal uniparental disomy was identified in three cases. Mosaic trisomy 16 detected through amniocentesis is not a benign finding but associated with a high risk of abnormal outcome, most commonly IUGR, CHD, developmental delay, and minor anomalies. The various outcomes may reflect the diversity of mechanisms involved in the resolution of this abnormality. As 80% of these patients were ascertained because of the presence of abnormal levels of MSAFP or MShCG, the increased use of maternal serum screening should bring more such cases to clinical attention.

Screening for Down syndrome with the femur length/biparietal diameter ratio: A new twist of the data

OBJECTIVE The purpose of this study was to determine the value of discordant morphometric measurements as identifiers of Down syndrome by evaluating the relationship of biparietal diameter, femur length, biparietal diameter/femur length ratio, and cephalic index between a group of fetuses with trisomy 21 and a control population. STUDY DESIGN Biometric measurements from 48 fetuses with trisomy were reviewed and compared with 107 normal fetuses of similar gestational age. Data were analyzed in 2-week gestational age intervals to determine the effect of gestational age on ultrasonographic detection of Down syndrome. Outcome measures were subject to least-squares linear regression and the t test for analysis. RESULTS A positive relationship between abnormal morphometric measurements and fetuses with Down syndrome was detected but only during specific weeks of pregnancy. CONCLUSION Although it appears that biometric measurements may be useful for Down syndrome, further study is needed before its widespread introduction into clinical practice.

Cook obstetrics and gynecology catheter multicenter chorionic villus sampling trial: Comparison of birth defects with expected rates

OBJECTIVE The null hypothesis was that offspring of women undergoing first-trimester chorionic villus sampling do not experience a rate of birth defects exceeding background rates. STUDY DESIGN Follow-up information regarding major malformations was prospectively sought on offspring of 4105 women undergoing first-trimester chorionic villus sampling from nine centers participating in a collaborative study with the Cook obstetrics and gynecology catheter. These data were compared with data from the Collaborative Perinatal Project and other registries. RESULTS A total of 84 offspring with major malformations was identified (2.36%). Compared with background rates, there was no increase in the incidence of total malformations or specific malformations (including limb reduction defects) in the subjects. One institution experienced all three limb reduction defects in this series; the probability of this occurring by chance alone is < 1%. CONCLUSION Chorionic villus sampling was not found to result in an increase in major birth defects or in specific categories of birth defects in this series.

Prenatal Diagnosis — When and How?

Advances in prenatal diagnosis provide new opportunities for patients and their physicians to distinguish the abnormal from the normal fetus. Demands from women to learn about their fetuses earlier...

Use of Three-dimensional Ultrasonography for Prenatal Diagnosis of Ambiguous Genitalia

Sex identification is one of the prime expectations of any parent during the prenatal ultrasound examination. However, the ability to visualize fetal genitalia not only has important social implications but also has considerable medical implications. Various endocrine disorders and complex genitourinary malformations can be manifested in the form of anomalous genitalia, and a delay in diagnosis may lead to an increase in postnatal morbidity and mortality. 1 In addition, correctly identifying and illustrating major fetal anomalies is of paramount importance to the parents, whose decisions regarding possible termination will directly affect the course of the pregnancy. Prenatal detection of genital abnormalities is therefore helpful in evaluating those fetuses with severe multisystem diseases and those with disorders more easily corrected with prenatal and neonatal treatments. Ambiguous genitalia is a condition that affects approximately 1 per 5000 live-born infants. Until the inception of three-dimensional (3D) ultrasonography, two-dimensional (2D) ultrasonography was the only method available to visually detect cases of ambiguous genitalia. A review of the literature reveals several case reports and small case series of prenatal identification of abnormal fetal genitalia during targeted 2D ultrasonographic surveys. However, the limitations of a standard 2D fetal sonogram are often evident. We present a case of ambiguous fetal genitalia whose diagnosis was both correctly identified and visually clarified by the use of prenatal 3D ultrasonography.

TRISOMY 21 : Second-Trimester Ultrasound

Not every aspect of sonographic examination reveals karyotypic abnormalities. Ultrasound examination of a fetus with trisomy 21 generally reveals normal amniotic fluid, normal placentation, and normal fetal growth. In addition, other chromosomal abnormalities have many of the same sonographic findings as Down syndrome, and many findings have a large overlap with phenotypically normal fetuses. The importance of second-trimester ultrasound screening for Down syndrome has remained great because of its ease of use and relative effectiveness. Trained sonographers can adjust the relative risk for trisomy 21 and alter the need for genetic amniocentesis. It is important that parents understand the limitations of a screening test and the risks and benefits of possible subsequent confirmatory testing. If a major structural abnormality is identified on ultrasound, karyotype determination should be considered. Nuchal thickness in the first or second trimester remains the most clinically useful marker for trisomy 21. The predictive value of all the markers depends on the population studied and can be modified by a host of biochemical markers and historical factors. If fetal karyotype analysis could be performed without sampling through the uterus, prenatal diagnosis could be offered to all pregnant women, and screening would be unnecessary. Despite its limitations, ultrasound will have an important role in prenatal diagnosis at least until isolating and testing fetal cells from maternal blood or other sources becomes practical and widely available. Whether used alone or in conjunction with additional biochemical or molecular serum markers, ultrasound is an important and powerful tool in prenatal genetic evaluation.

Resolution of Hydrops Fetalis Despite Persistent Fetal Tachycardia

Digoxin is the most commonly used medication in the treatment of fetal supraventricular tachycardias (SVTs). Reports have varied with regard to the percent transfer of maternally administered digoxin across the placenta, ranging from 100% 1 to virtually zero, 1-3 because the extent and severity of hydrops present in the placenta and fetus affect the rate of transfer. There are, however, numerous reports of successful conversion to a normal fetal heart rate after maternal administration of digoxin with or without the addition of other therapeutic agents. 1,2,4 We report a case in which maternally administered digoxin was successful in reversing fetal hydrops without restoration of a normal fetal heart rate. This supports the view by Kleinman et al 3 that in this case without rate control, digoxin also works by improving systolic function in a relatively noncompliant fetal ventricle.

Mid-Trimester Ruptured Cornual Pregnancy

A case involving a woman with normal sonographic findings at genetic amniocentesis who had a ruptured cornual ectopic pregnancy at 19 weeks gestation is discussed.