Assessment of free fetal DNA concentration in maternal plasma during the first trimester of pregnancy: comparative study between EDTA and PPT tubes - pilot study.

OBJECTIVE: To compare ethylenediamine tetraacetic acid (EDTA) tubes and plasma preparation tubes (PPT) for evaluating maternal plasma during the first trimester of pregnancy. METHODS: A cross-sectional study was conducted on 24 male fetuses in women between 6 and 14 weeks of pregnancy. Blood samples (10 mL) were collected and stored in EDTA and PPT tubes. Subsequently, the samples were centrifuged and sent for free fetal DNA extraction by means of the polymerase chain reaction (PCR) technique. The reactions were performed in a real time PCR machine for detecting the amplification products. The genome region chosen for performing the PCR reactions was a target specific for the Y chromosome, in which the DYS-14 marker was amplified only when the DNA was of male sex. The free fetal DNA concentration was given by the threshold cycle (TC). To compare the tubes, the paired Student t-test was used. RESULTS: The mean gestational age was 11.08 ± 2.30 weeks (range: 6-14). The mean TC for PPT was 30.08 ± 1.05 (range: 27.08-32.61) and for EDTA, 30.23 ± 0.96 (range: 28.01-32.09), but without statistical significance (p=0.357). CONCLUSION: We did not observe any statistically significant difference in free fetal DNA concentration between the EDTA and PPT tubes.

Prenatal diagnosis of a fetus with ring chromosomal 15 by two- and three-dimensional ultrasonography.

We report on a prenatal diagnosis of ring chromosome 15 in a fetus with left congenital diaphragmatic hernia (CDH) and severe intrauterine growth restriction (IUGR). A 31-year-old woman, gravida 2 para 1, was referred because of increased nuchal translucency at gestational age of 13 weeks. Comprehensive fetal ultrasound examination was performed at 19 weeks revealing an early onset IUGR, left CDH with liver herniation, and hypoplastic nasal bone. Three-dimensional ultrasound (rendering mode) showed low set ears and depressed nasal bridge. Amniocentesis was performed with a result of a 46,XX,r(15) fetus after a cytogenetic study. A 1,430 g infant (less than third percentile) was born at 36 weeks. The infant presented with respiratory failure and died at 2 h of life. Postnatal karyotype from the umbilical cord confirmed the diagnosis of 15-ring chromosome. We described the main prenatal 2D- and 3D-ultrasound findings associated with ring chromosome 15. The interest in reporting the present case is that CDH can be associated with the diagnosis of 15-ring chromosome because the critical location of the normal diaphragm development is at chromosome 15q26.1-q26.2.

Reference ranges for 2-dimensional sonographic lung measurements in healthy fetuses: a longitudinal study.

OBJECTIVES: The purpose of this study was to establish reference ranges for 2-dimensional sonographic measurements of fetal lungs from longitudinal data. METHODS: A total of 214 fetal lung measurements were longitudinally evaluated in 62 healthy fetuses between 20 and 36 weeks' menstrual age. Both right and left lung areas were measured in the heart 4-chamber view using lung area tracing and axis diameter methods. Multilevel modeling was used to evaluate the expected values and variability with respect to menstrual age and to generate reference ranges for the lung area, lung-to-head ratio, quantitative lung index, and observed-to-expected lung-to-head ratio for both lungs. RESULTS: The expected values varied with menstrual age for all parameters. Variance was menstrual age dependent for all parameters except the longest diameter area measurements and their lung-to-head ratios. CONCLUSIONS: Models are presented for expected 2-dimensional sonographic lung size parameters and their variance as a function of menstrual age. These data have been used to generate age-specific reference ranges for both measurements and indices.

Prenatal diagnosis of a large epignathus teratoma using two-dimensional and three-dimensional ultrasound: correlation with pathological findings.

Epignathus teratomas are rare tumors that originate in the region of the palate or pharynx and are known as Rathke pouch. They may be associated with other malformations such as a cleft palate and bifid tongue or nose. The prenatal diagnosis can be established by two-dimensional ultrasonography showing a heterogeneous mass protruding through the mouth of the fetus. The three-dimensional ultrasonography in rendering mode permits better understanding of this anomaly by the parents, facilitating the counseling. The importance of prenatal diagnosis lies in the fact that this tumor may obstruct the airways, thus leading to death at birth due to respiratory insufficiency. We report a case of prenatal diagnosis of epignathus teratoma in the 30th week of pregnancy by two-dimensional ultrasonography. We focus on the importance of three-dimensional ultrasonography in rendering mode for demonstrating the spatial relationships of the tumor with the oral cavity and provide correlations between the ultrasound images and the anatomopathological findings.

Prenatal diagnosis of treacher-collins syndrome using three-dimensional ultrasonography and differential diagnosis with other acrofacial dysostosis syndromes.

Treacher-Collins syndrome (TCS) is a rare dominant autosomal anomaly resulting from malformation or disruption of the development of the first and second branchial arches. It is characterized by micrognathia, malar hypoplasia, and malformations of the eyes and ears. The prenatal diagnosis using two-dimensional ultrasonography (2DUS) is characterized by identification of facial malformations together with polyhydramnios. Three-dimensional ultrasonography (3DUS) has the capacity to spatially display these facial malformations, thus making it easy for the parents to understand them. We present a case of TCS diagnosed in the 33rd week using 3DUS, with postnatal confirmation using cranial computed tomography and anatomopathological analysis.

New anatomical landmarks to study the relationship between fetal lung area and thoracic circumference by three-dimensional ultrasonography.

OBJECTIVE: To evaluate the relation between total lung area (TLA) and thoracic circumference (TC) ratio by three-dimensional (3D) ultrasonography applying new anatomical landmarks as the fetal aorta and inferior angle of the scapula. METHODS: A longitudinal prospective study was conducted with 56 uncomplicated pregnancies between 24 and 32 weeks of gestation. Polynomial regressions were used to evaluate the correlation between TC and gestational age (GA) as well as TC and estimated fetal weight (EFW). A simple linear regression was used to evaluate the correlation between TLA and Total thoracic area (TTA) and GA. The intraclass correlation coefficient (ICC) was used to assess the intra and interobserver variability. RESULTS: 127 examinations were performed. TC values ranged from 150 to 174 mm (mean 166 mm) at 24 weeks and 215-248 mm (mean 231 mm) at 32 weeks. The TLA/TC ratio ranged from a mean of 0.64 at 24 weeks (range 0.56-0.70) to 0.90 at 32 weeks gestation (range 0.79-1.01). The intraobserver variability using the ICC was of 0.919 for TC; 0.916 for TTA; 0.860 for right lung area (RLA) and 0.910 for left lung area (LLA). Interobserver reproducibility was with an ICC of 0.970 for TC; 0.984 for RLA and 0.910 for LLA. CONCLUSIONS: Measurement of fetal TC and the relationship between TLA and TC by 3D-ultrasonography applying new anatomical landmarks shows good reproducibility and allows a new assessment of thoracic and lung growth.