Evaluation of Fetal Bladder Emptying During the 11-14 Weeks' Ultrasound Examination as a Negative Predictive Marker for Chromosomal Abnormalities

Condition(s) studied

Investigational drug(s) / intervention(s)

40-Minute Real-Time First-Trimester Ultrasonography: A one-time midsagittal ultrasound performed between 11 +0 and 14 +0 weeks. Bladder emptying time and post-void longitudinal bladder diameter are recorded. No invasive procedures are performed.

Study summary

Template-Based Brief Summary (Sağlık Profesyonelleri İçin)

Study Title:

The Negative Predictive Value of First-Trimester Fetal Bladder "Rapid Emptying" (≤40 minutes and post-void ≤2 mm) for Major Chromosomal Aneuploidies: A Prospective Diagnostic Accuracy Study.

Purpose:

To evaluate whether the dynamic phenotype of rapid bladder emptying at 11-14 weeks reduces the likelihood of major chromosomal abnormalities (particularly Trisomy 21) compared to fetuses without this phenotype.

Design:

Single-center, prospective observational cohort.

Population:

270 singleton pregnancies between 11+0 and 14+0 weeks.

Procedures:

Real-time sagittal ultrasound observation for 40 minutes.

Documentation of bladder emptying time and post-void longitudinal bladder diameter.

Concurrent measurement of CRL, NT, ductus venosus waveform.

Gold standard confirmation with cfDNA or invasive karyotyping in high-risk cases.

Primary Endpoint:

Negative predictive value (NPV), ROC-AUC, sensitivity/specificity for aneuploidy detection.

Secondary Endpoints:

Rate of invasive testing, performance in combined models with cfDNA and biophysical markers, Net Reclassification Index.

Duration:

5 months (08/2025 - 01/2026).

Potential Impact:

If validated, the rapid emptying phenotype may serve as a low-risk marker, reduce unnecessary invasive procedures, and refine first-trimester screening algorithms.

Eligibility

Primary outcome measure(s)

• Negative Predictive Value (NPV) of Rapid Fetal Bladder Emptying for Detecting Major Chromosomal Aneuploidy — From enrollment at 11 + 0 to 14 + 0 gestational weeks until definitive genetic result or delivery, whichever comes first (≈ 26 weeks).
  Proportion of fetuses with the rapid-emptying phenotype (≤ 40-minute complete emptying + post-void longitudinal bladder diameter ≤ 2 mm) who are subsequently confirmed not to have a major chromosomal aneuploidy (Trisomy 21, 18, or 13) by cfDNA, invasive karyotype, or postnatal testing.

Trial sites (1)

More Haseki Training and Research Hospital trials in Turkey