Trisomy 13 syndrome: prenatal US findings in a review of 33 cases.

PURPOSE

To determine the type and prevalence of prenatal ultrasound (US) findings in fetuses with trisomy 13.

MATERIALS AND METHODS

Prenatal US findings in 33 consecutive fetuses with trisomy 13 and in 200 karyotypically normal fetuses were reviewed and compared.

RESULTS

One or more abnormalities were found in 30 fetuses (91%). Major anomalies detected by means of US included holoprosencephaly (13 [39%]) or other central nervous system anomalies (19 [58%]), facial anomalies (15 [48%]), and renal (11 [33%]) and cardiac (16 [48%]) defects. Growth retardation was also present in 16 (48%). Echogenic chordae tendineae were seen in 10 (30%), which includes seven (39%) of 18 fetuses examined before 20 menstrual weeks (compared with four [2%] of 200 fetuses in the reference group [P < .001]). Other findings not generally associated with trisomy 13 but present in this series included a large cisterna magna (six [18%]), mild cerebral ventricular dilatation (three [9%]), nuchal thickening or cystic hygroma (seven [21%]), and a hypoplastic left side of the heart (seven [21%]).

CONCLUSION

Prenatal US can help detect one or more anomalies in most fetuses with trisomy 13; thus, US finding can indicate whether karyotype should be tested.