Is genetic amniocentesis warranted when isolated choroid plexus cysts are found?
D L Gray1, R C Winborn, T L Suessen
1Department of Obstetrics and Gynecology, Washington University School of Medicine, St Louis, Missouri, USA.
Prenatal Diagnosis
|November 1, 1996
Summary
Isolated fetal choroid plexus cysts are rarely associated with trisomy 18. The presence of these cysts alone does not warrant the risks of genetic amniocentesis for trisomy 18 screening.
Area of Science:
- Prenatal diagnosis
- Fetal medicine
- Genetics
Background:
- Fetal choroid plexus cysts are common findings during mid-trimester ultrasounds.
- Trisomy 18 is a serious chromosomal abnormality with significant implications for fetal development.
Purpose of the Study:
- To determine the prevalence of trisomy 18 in fetuses with isolated choroid plexus cysts.
- To compare the risk of trisomy 18 with the risks associated with genetic amniocentesis.
Main Methods:
- Prospective collection of 18,861 fetuses in the mid-trimester with known outcomes.
- Retrospective review of scans for cyst characteristics (size, laterality, complexity).
- Statistical analysis (Chi-square) to compare trisomy 18 rates in fetuses with and without cysts.
Main Results:
- 1.1% of fetuses had choroid plexus cysts; 3.4% of these had trisomy 18.
- Of all trisomy 18 cases, 44% had choroid plexus cysts; none had cysts as the sole sonographic finding.
- Cysts ≥10 mm were more frequently associated with trisomy 18 than normal karyotypes (P < 0.01).
Conclusions:
- Isolated choroid plexus cysts in otherwise normal fetuses do not independently justify genetic amniocentesis.
- Cyst size may be a more relevant factor than laterality or complexity in assessing trisomy 18 risk.
- Risk assessment for trisomy 18 should consider multiple sonographic findings and maternal factors.
