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.

Inclusion Criteria:

• Singleton, viable pregnancy between 11 + 0 and 14 + 0 gestational weeks (GA)
• Maternal age 18 - 45 years at enrollment
• Able to provide written informed consent

Exclusion Criteria:

• Multiple gestation (twins, higher order)
• Major fetal structural anomaly detected at index scan
• Known serious maternal comorbidity (e.g., insulin-dependent diabetes, uncontrolled hypertension, renal or autoimmune disease)
• Participation in another interventional research study during the current pregnancy

Prospective cohort of 270 consecutive healthy pregnant women with singleton fetuses, attending first-trimester screening (11 - 14 GA) at a tertiary perinatology center in Istanbul, Türkiye.

De-identified individual participant data (IPD) underlying the primary and secondary outcome analyses-including fetal bladder emptying time, post-void longitudinal bladder diameter, nuchal translucency, ductus venosus waveform, cfDNA results, and karyotype confirmation-will be shared with qualified researchers upon reasonable request.

De-identified IPD, çalışma protokolü, SAP ve boş ICF; ana sonuçların hakemli dergide yayımlanmasından itibaren 12 ay içinde erişime açılacak ve 5 yıl süreyle paylaşılabilir olacaktır (yaklaşık Temmuz 2027 - Temmuz 2032).