Health & Medicine

Study Reveals Kidney Health Begins before Birth

Benita Matilda
First Posted: May 31, 2013 07:49 AM EDT

A new study states that conditions in the womb can affect kidney development and have serious health implications for the child, even decades after birth.

The study, published in The Lancet, was conducted by a team of international researchers that included John Bertram from Monash University and Wendy Hoy from University of Queensland.

For the study, researchers examined peer-reviewed research on kidney health and developmental programming - the effects of the in-utero environment on adult health.

The data clearly pointed to a strong association between low birth weight and prematurity, with lesser number of the kidney's filtration units or 'nephrons', which are risk factors for high blood pressure and chronic kidney disease later in life.

According to the study report, nearly 30 percent of the adult population in Australia has high blood pressure, and one in nine has at least one clinical symptom of chronic kidney disease. The occurrence of both these diseases are higher in the indigenous population.

Before birth, the kidney is very sensitive, because one stops making nephrons at 36 weeks of gestation. Hence in babies born at term, the nephron formation is complete and cannot be started again, says Bertram, Head of the Department of Anatomy and Developmental Biology.

On average, a human is born with one million nephrons and nearly 6,000 is lost each year. But Bertram's research shows that there exists a huge variation in nephron numbers, from over 200,000 to two million; further, the number of nephrons are linked to birth weight. Low birth weight means lesser number of nephrons, and larger babies have a higher nephron number.

With 15 percent cases of low birth weight occurring worldwide, the new study has suggestions for maternal health and clinical screening processes.

"In terms of maternal health during pregnancy, things like a high fat diet, alcohol consumption, various antibiotics and stress hormones have been shown to have a negative impact on foetal kidney development, although more research needs to be done," Bertram said. "Further, given the strong associations between birth weight, nephron number and disease later in life, and the fact that a baby's weight is routinely recorded in many countries, we suggest that birth weight should be a parameter that clinicians use to determine how often a patients screened for kidney function or given a blood pressure test."

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