Isolated fetal pyelectasis and the risk of Down syndrome: a meta-analysis
Article first published online: 27 OCT 2013
Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Ultrasound in Obstetrics & Gynecology
Volume 42, Issue 6, pages 615–621, December 2013
How to Cite
Orzechowski, K. M. and Berghella, V. (2013), Isolated fetal pyelectasis and the risk of Down syndrome: a meta-analysis. Ultrasound Obstet Gynecol, 42: 615–621. doi: 10.1002/uog.12516
- Issue published online: 24 NOV 2013
- Article first published online: 27 OCT 2013
- Accepted manuscript online: 27 MAY 2013 11:50AM EST
- Manuscript Accepted: 13 MAY 2013
- isolated fetal pyelectasis;
- prenatal diagnosis;
- risk adjustment;
- trisomy 21
We performed a meta-analysis to examine the performance of second-trimester (14–24 weeks' gestation) isolated fetal pyelectasis as a marker for trisomy 21 and to calculate its associated weighted pooled likelihood ratios.
PubMed, Ovid MEDLINE and Cochrane databases were searched using the terms ‘pyelectasis’ and ‘pelviectasis’. Studies were included if fetuses with isolated pyelectasis were reported separately from fetuses with other soft markers of aneuploidy and/or structural anomalies and if knowledge of the fetal karyotype was unknown at the time of ultrasound examination.
Individual study statistics were pooled as weighted positive and negative likelihood ratios with 95% CIs, using a random-effects model. Ten observational studies were included (2148 cases of isolated pyelectasis). Isolated fetal pyelectasis was defined in seven out of 10 studies as a renal pelvis anteroposterior diameter of ≥ 4 mm. Isolated fetal pyelectasis was associated with pooled positive and negative likelihood ratios of 2.78 (95% CI, 1.75–4.43) and 0.99 (95% CI, 0.98–1.00), respectively.
The detection of isolated fetal pyelectasis on mid-trimester ultrasound is associated with an increased likelihood of trisomy 21. If the finding of isolated fetal pyelectasis is used to adjust the trisomy 21 risk from maternal serum screening tests, a positive likelihood ratio of 2.78 should be used in the calculation. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.