High blood pressure may start in the womb

New research supports the theory that some cases of high blood pressure may have roots that go back to fetal development. According to researchers, their findings suggest that proper nutrition during pregnancy could be a very early way to cut the risk of high blood pressure years later. Nephrons are the tiny filtration units that do the kidneys' work of expelling waste and excess fluid from the body, a process that plays an important role in regulating blood pressure. The nephron number is set during fetal development, and a normal kidney is estimated to contain about 1 million nephrons, although that number varies among individuals. The authors of the new study suspect that the lower nephron number they found in individuals with high blood pressure is the result of their having been born with a relatively lower number of nephrons. Researchers at the University of Erlangen-Nurnberg in Germany used a three-dimensional method to compare the number and volume of glomeruli in 10 middle-aged white patients (age range, 35 to 59 years) with a history of primary hypertension with the number and volume in 10 subjects matched for sex, age, height, and weight. All 20 subjects had died in accidents. The new findings are in line with recent work suggesting that prenatal factors can have health effects that last into adulthood. There is evidence that low birth weight is linked to a higher risk of cardiovascular disease. This latest study shows that people with primary hypertension (high blood pressure not caused by another disease) may have fewer nephrons in their kidneys than people with normal blood pressure do. Although much more research is needed, these early findings point to the potential importance of prenatal nutrition in determining a person's eventual vulnerability to high blood pressure. There is evidence that low protein intake during pregnancy could affect nephron number in the fetus, as well as the risk of high blood pressure and other types of cardiovascular disease in adulthood. Improving nutrition for pregnant women could be one strategy in preventing low nephron number and perhaps also hypertension.