Objective To examine the association between absence of the nasal bone at the 11-14-week ultrasound scan and chromosomal defects. NT < 2.5 mm, for NT ≥ 4.5 mm. In the chromosomally abnormal group the nasal bone was absent in 161/242 (66.9%) with trisomy 21, in 48/84 (57.1%) with trisomy 18, in 7/22 (31.8%)
Methods
Objective To determine the possible association between single umbilical artery (SUA) at 11-14 weeks of gestation and the incidence of chromosomal abnormalities.
Methods
Evaluation of most part of the fetal anatomical structures is feasible with high accuracy in the first trimester. Visualization of the majority of the targeted fetal organs improves from 11 to 13 weeks.
Pulsed‐Doppler ultrasound assessment of blood flow was performed simultaneously in the fetal middle cerebral artery, umbilical artery, and uteroplacental vessels to verify the incidence of velocimetric abnormalities, as well as their predictive value towards adverse perinatal outcome. Eighteen normal pregnancies and 32 complicated pregnancies (intrauterine growth retardation, pregnancy‐induced hypertension, chronic hypertension and pre‐eclampsia) have been examined between 30th and 40th week of gestation. Waveform abnormalities were detected even in the control group, more frequently in the cerebral artery (11.1%) and umbilical artery (5.5%) than in uteroplacental arteries. Umbilical artery abnormalities were found in intrauterine growth retardation, pregnancy‐induced hypertension, and preeclampsia; while the highest number of anomalous Doppler waveforms in the middle cerebral artery was seen in 71.4% of patients with pregnancy‐induced hypertension. Pathological umbilical artery patterns have shown a diagnostic accuracy of 62% in identifying adverse perinatal outcome. Both middle cerebral artery and uteroplacental vessels demonstrated a diagnostic accuracy of 58%. The false positive rate is 6% for the umbilical artery, 8% for the middle cerebral artery, and 0% for uteroplacental vessels, contrary to current methods of fetal surveillance (such as nonstress test, contraction stress test and biophysical profile), which have a false‐positive rate ranging from 30% to 70%.
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