Correlation of Sonographic Gestational Age with Fetal Kidney Length in Normal Pregnancy

Abstract

Precise evaluation of gestational age is essential for quality maternity care. Ultrasonography is the most readily available and reliable method to establish gestational age. This study aims to use the length of the fetal kidney as a reliable parameter to measure gestational age in late second and third trimesters.  Objective: To determine the relationship between fetal kidney length and gestational age in weeks during the late 2nd and 3rd trimester of normal pregnancy.  Methods: It was a prospective cross-sectional study conducted on 105 singleton normal pregnant females between 24th and 40th weeks of gestation who came to the obstetrics and gynecology department at a private sector hospital in Kharian, Pakistan. The duration of the study was four months. Bi-parietal diameter, femur length, and fetal kidney lengths were measured. Statistical analyses were applied using SPSS version 22.0. Results: A moderately significant positive correlation was identified between different gestational age measuring parameters and fetal kidney length. The correlation was significant at the level of 0.01. The correlational values of GA according to LMP with FKLL and FKLR were (r= .85**) and (r= .87**) respectively. GA with BPD indicates a moderately significant positive correlation with FKLL and FKLR (r= .94**) and (r=.94**). GA with FL also shows a moderately significant positive correlation with FKLL and FKLR (r= .83**) and (r= .83**), respectively.  Conclusion: In conclusion, fetal kidney length in millimeters correlates well with gestational age in weeks and shows linear growth with gestational age throughout pregnancy. Gestational age estimated from fetal kidney length gives improved dating of fetal age