ABSTRACT
OBJECTIVE: To investigate whether three-dimensional (3D) technology offers any advantage over two-dimensional (2D) ultrasound in fetal biometric measurement training. METHODS: Ten midwives with no hands-on experience in ultrasound were randomized to receive training on 2D or 3D ultrasound fetal biometry assessment. Midwives were taught how to obtain fetal biometric measurements (biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL)) by a trainer. Subsequently, each midwife measured the parameters on another 10 fetuses. The same set of measurements was repeated by the trainer. The percentage deviation between the midwives' and the trainer's measurements was determined and compared between training groups. Time required for completion was recorded. Frozen images were reviewed by another sonographer to assess the image quality using a standardized scoring system. RESULTS: The median time for the complete set of measurements was significantly shorter in the 2D than in 3D group (13.4 min versus 17.8 min, P = 0.03). The mean percentage deviations did not reach statistical significance between the two groups except for FL (3.83% in 2D group versus 2.23% in 3D group (P = 0.046)). There were no significant differences in the quality scores. CONCLUSIONS: This study showed that the only demonstrable advantage of 3D ultrasound was a slightly more accurate measurement of FL, at the expense of a significantly longer time required.
Subject(s)
Biometry/methods , Body Weights and Measures/methods , Imaging, Three-Dimensional , Ultrasonography, Prenatal/methods , Body Weights and Measures/statistics & numerical data , Clinical Competence , Diagnostic Techniques, Obstetrical and Gynecological , Education, Medical, Continuing , Female , Gestational Age , Humans , Image Interpretation, Computer-Assisted , Imaging, Three-Dimensional/methods , Midwifery/education , Pregnancy , Time Factors , Ultrasonography, Prenatal/statistics & numerical dataABSTRACT
BACKGROUND: The molecular characteristics of placental RNA circulating in maternal plasma are unknown. We investigated the integrity of circulating placental RNA in maternal plasma and tested the relevance of plasma RNA integrity for noninvasive prenatal diagnosis. METHODS: Six different placental transcripts and mRNA of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were quantified for the 5' and 3' regions in maternal plasma by 1-step real-time reverse transcription-PCR (RT-PCR) assays. This quantitative strategy was validated by 2-step RT-PCR and serial dilution experiments. The rates of detection by the 5' and 3' assays for the beta-subunit of human chorionic gonadotropin (beta hCG) were assessed in maternal plasma samples collected from different gestational periods. RESULTS: For 5 of the 7 genes, the plasma mRNA concentrations measured by the 5' amplicons were significantly higher than those measured by the corresponding 3' amplicons. Every transcript under study demonstrated a higher rate of detection in the 5' assay than in the 3' assay in maternal plasma. In particular, the detection rate of beta hCG mRNA in maternal plasma was increased throughout gestation when the 5' assay was used. CONCLUSIONS: Circulating placental RNA is associated with a preponderance of 5' mRNA fragments in maternal plasma. Apart from its intrinsic biological interest, this information could have important implications for the development of new assays targeting fetal RNA markers for noninvasive prenatal diagnosis and monitoring.
