Renal Function and Renal Volume of Children Born with Very Low Birth Weight

Author(s): Sharath Babu M. V.1 , Parvathi R.2 , Mini M. V.3

BACKGROUND Low birth weight is a risk factor for hypertension and renal disease later in life. Impaired nephrogenesis in low birth weight babies is a postulated cause. Monitoring these babies for kidney size and glomerular function as they grow is important. METHODS A cross sectional study was conducted on school aged children born with birth weight below 1500 gms on follow up in the high risk newborn clinic of a government hospital in South India. Medical records were reviewed to assess the perinatal risk factors that could contribute to nephron loss. Anthropometric measurements and blood pressure were recorded. Renal volume was measured by ultra sound examination and renal function by glomerular filtration rate. RESULTS The study population consisted of 50 children between 6 to 8 years born with very low birth weight. Seven children had stage 1 hypertension. Glomerular filtration rate (GFR) was abnormal in forty-two (84%) children. Renal volume was found to be reduced in 33 (66%) children (p=0.013). A significant association was found between maternal pregnancy induced hypertension (PIH) (p=0.09), antenatally detected intrauterine growth restriction (IUGR) (p=0.018) and reduced renal volume. Weight of 40 (80%) and height of 45 (90%) of these children were found to be in the normal range as per WHO growth charts. CONCLUSIONS Renal volume was found to be reduced in more than two thirds of children born with very low birth weight, especially those born to mothers with PIH and those with IUGR. Continued follow up is necessary to detect deterioration of renal function in these babies.