Validity of Fetal Kidney Length for Gestational Age Estimation among Pregnant Women doing Antenatal Care in October 6 University Hospital

Authors

  • Ahmed Hussein Mohamed Abdel Aal
  • Tarek Mohamed Said El-Azizi
  • Hussien A. M. Abo Sheashaa
  • Mahmoud Mostafa Assem

Keywords:

Gestational Age Estimation, Fetal Kidney Length

Abstract

 

Background: Accurate gestational age (GA) estimation is crucial for optimal antenatal care, particularly in late-presenting pregnancies where conventional biometric parameters lose reliability. Fetal kidney length (FKL) has emerged as a potential alternative due to its consistent growth pattern and resistance to growth disturbances.

Objective: This study aimed to evaluate the validity of FKL for GA estimation in the second and third trimesters compared to first-trimester crown-rump length (CRL) and conventional biometric parameters.

Patients and Methods: A cross-sectional study was conducted at October 6 University Hospital, including 100 pregnant women (24–39 weeks) with documented first-trimester CRL. A single radiologist performed standardized ultrasound measurements of FKL (longitudinal pole-to-pole) and conventional parameters (BPD, HC, AC, FL). Statistical analysis included Pearson’s correlation, linear regression, Bland-Altman analysis, and mean absolute error (MAE) calculations.

Results: FKL showed a strong correlation with CRL-based GA (*r* = 0.89, *p* < 0.001), with a linear growth rate of 1.32 mm/week (95% CI: 1.18–1.46). FKL-based GA estimation demonstrated superior accuracy (MAE = 0.8 weeks) compared to BPD (1.5 weeks), HC (1.3 weeks), AC (1.4 weeks), and FL (1.2 weeks). Bland-Altman analysis revealed minimal bias (0.3 days) between FKL and CRL-based GA. Right-left kidney measurements showed excellent agreement (ICC = 0.92). FKL also exhibited strong diagnostic performance for preterm/post-term classification (AUC 0.93 and 0.87, respectively).

Conclusion: FKL is a reliable and accurate parameter for GA estimation in late pregnancy, outperforming conventional biometrics. Its consistent growth and reproducibility support its clinical adoption, particularly when early ultrasound dating is unavailable.

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Published

2025-05-12

How to Cite

1.
Hussein Mohamed Abdel Aal A, Mohamed Said El-Azizi T, A. M. Abo Sheashaa H, Mostafa Assem M. Validity of Fetal Kidney Length for Gestational Age Estimation among Pregnant Women doing Antenatal Care in October 6 University Hospital. J Neonatal Surg [Internet]. 2025May12 [cited 2025Sep.23];14(21S):1242-8. Available from: https://jneonatalsurg.com/index.php/jns/article/view/5658

Issue

Vol. 14 No. 21S (2025): Journal of Neonatal Surgery

Section

Original Article

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