* Ultrasound Division, ASL Roma B, Rome, Italy.
** Ultrasound Division, Ceprano Hospital, Ceprano, Italy.
Case report
This is the case of a 30-year-old G2 P1 with non-contributive personal and family history. Her first ultrasound examination at 8 weeks was unremarkable and biometry was consistent with the length of amenorrhea.
The next ultrasound examination which was performed at 16 weeks of gestation showed the following findings:
- Nasal bone hypoplasia
- Prefrontal edema
- Ventriculomegaly
- Ventricular septal defect
- Reverse flow in the ductus venosus
- Dilated and echogenic bowel
- Hypoplastic right umbilical artery
- Ascites
- Generalized fetal hydrops
The ratio between the biparietal diameter (BPD) and length of the nasal bone (NB) remains constant in the fetuses at 15-20 weeks of gestation. Bromley et al. found that when this ratio BPD/NB was ≥10, then 81% fetuses were affected with trisomy 21 and only 11 % were fetuses with normal karyotype [1]. In our case this ratio BPD/NB was more than 10 (BPD=33 mm, NB=2.5 mm).
The width of the lateral ventricles was within the normal limit but the choroid plexus was shifted to the periphery of the ventricle. The distance between the glomus of the choroid plexus and medial wall of the lateral ventricle, so-called “choroid plexus separation”, was increased 5.2 mm, the normal distance is ≥4 mm [2].
The three vessels cord had hypoplastic right umbilical artery. It's diameter was less than half of the left umbilical artery. It has been shown that this condition is associated with aneuploidies [3].
Blood analysis was negative for HIV, TORCH, hepatitis B and C and parvovirus B19. The patient was Rh positive and the indirect Coombs test performed in order to rule out AB0 incompatibility was negative.
There was the intrauterine fetal demise before the scheduled amniocentesis. The karyotype from the aborted fetus was 47,XX,+21, trisomy 21.
Images 1,2: 16 weeks, image 1 shows a profile of the baby, note the prefrontal edema and short nasal bone (2.5 mm). Image 2 shows the choroid plexus separation.