Estimation of gestational age using foetal kidney length during second and third trimester in south Indian population

Introduction and Aim: Gestational age assessment in women with indeterminate last menstrual period has always remained an enigma. Though multiple parameters have been found useful in providing an indirect age assessment, various studies have now shown that the ultrasonographic measurement of foetal kidney length during the second and third trimester of pregnancy is a viable alternative in foetal age assessment. Methods: This prospective study was conducted among the antenatal women with singleton uncomplicated pregnancy during 18 to 40 weeks of gestation attending the outpatient department for routine ultrasound foetal biometry in a tertiary care referral institution in South India, during January 2019 to June 2019. A total of hundred and thirty-five antenatal mothers were included in this study. Data entry was done in Microsoft Excel and data analysis was done using Statistical Package for Social Sciences (SPSS). Results: There was a strong positive correlation between GA and MKL. Regression model (Model 1) for Mean kidney length showed significant correlation and regression models (Model 2) for MKL and routine foetal biometric parameters like biparietal diameter, femur length and abdominal circumference were found to be significantly correlated. Conclusion: Mean foetal kidney length can alone predict gestational age and by combining it with the other biometric indices to give a better estimation of gestational age.

Kidney length, a visceral parameter predicts foetal age between 24 to 40 weeks of gestation

Background: Accurate estimation of gestational age is important in providing appropriate antenatal care. Recent evidence suggests that weightage should also be given to kidney length in addition to standard biometric parameters in determining the duration of pregnancy by ultrasound.Methods: In a single centre, prospective cross-sectional study was done in 120 pregnant women. In addition to standard biometric parameters, kidney length was also measured between 24 to 40 weeks at two-week intervals. A total of 240 renal vertical measurements were done and average of right and left renal lengths was taken as a final kidney length. Descriptive analysis was carried out to find the mean and standard deviations for each variable. Regression analysis was carried for each variable either singly or in combinations and Pearson regression coefficients was used to find the association between gestational age and various foetal parameters and to determine which of the regression model gives the best fit for prediction of gestational age.Results: Foetal kidney length progressively increased throughout the gestation (from 23.2 mm at 24 weeks to 40.1 mm at 40 weeks). The regression formula using only kidney length as an independent variable (gestational age=2.195±0.942 X kidney length) had high degree of correlation (R2 0.97, p<0.001, SE of prediction 4.7±3.9), which was superior to other prediction models using standard biometric parameters. In multiple regression models using several conventional parameters, when femur length was added in a stepwise manner, there was significant improvement in forecasting gestational age.Conclusions: Present study showed that foetal kidney length is a reliable indicator of gestational age between 24 to 40 weeks of pregnancy and may be of utility in pregnancies with wrong dates, non-availability of dating scan and women who have conceived during lactational period.

Prenatal glomerular changes during development of human foetal kidney

Background and aims: The cortical glomerulus shows many developmental changes during fetogenesis. Nonnalhistologyofthe fetal glomerulus at various stages of development was studied to get insight into the morphology of fetal glomerulus. Fetal glomerular study is a necessity for correlation with increase in gestational age and pathological changes which may affect the normal functioning of kidneys in fetal life. Method: Dissection of 70 normal human fetuses was carried out and histological findings of glomerulus were noted with respect to the age of fetus. The histology of fetal kidney was studied using H & E stain. Important developmental stages of glomerulus were observed. Results: Fetal kidney glomerulus histology is different from adult. Unlike in adult kidney, foetal kidney glomerulus shows many developmental stages as v, c, s, cresentric in starting phase. Multiple rows arrangement in between mednllary rays with well developed mature glomeruli at juxtamednllary junction. Capillary invagination with developed Juxta glomerular apparatus was appreciated. Nephrogenic zone which was found as hroad band in early gestational weeks disappeared near term. Conclusion: The present study will be helpful in understanding the normal histological architecture of foetal kidney glomerulus and add to the existing knowledge regarding development of foetal kidney, its relation with gestational age and pathogenesis.