FRIDAY, Aug. 16, 2002 (HealthDayNews) -- High blood pressure in adults is linked to a host of lifestyle factors, from diet to exercise to smoking.
However, it's possible the origins of high blood pressure could begin before you're even born, a new Australian study says.
Researchers used ultrasound to measure the length of the thigh bone and the circumference of the head and abdomen in 707 developing fetuses five times throughout the course of otherwise normal pregnancies.
Six years later, researchers made these same measurements on 300 of the children. Neither head nor abdomen circumference was linked to later blood pressure, according to the study.
But thigh length was.
The researchers found the longer the thigh bone, the lower the systolic blood pressure later in life. Systolic blood pressure is the higher number of the blood pressure reading. The shorter the thigh bone, the higher the blood pressure reading.
What does it mean?
A growing body of evidence suggests conditions in the womb set the stage for adult diseases such as hypertension, heart disease and diabetes later in life, says study author Dr. Kevin Blake, with the Department of Obstetrics and Gynecology at the University of Western Australia.
"Hypertension, as a risk factor for cardiovascular disease, is currently viewed as a chronic degenerative disease with an onset in middle age," Blake says. "Over the past 15 years or so, there is a growing awareness of the role of intrauterine development in determining the risk of disease in adulthood."
The study appears in the September issue of the Journal of Epidemiology and Community Health.
Doctors have known for a long time that babies born with a low birth-weight tend to have higher systolic blood pressure in childhood, a finding that was confirmed by this study, Blake says. However, this study suggests the "fetal programming" may start as early as 24 weeks, earlier in pregnancy than previously believed, Blake adds.
Short thigh bones can be a sign that something is going wrong with the pregnancy, usually that the placenta is not providing the baby with adequate nutrients to grow properly, says Dr. F. Ralph Dauterive, chief of obstetrics at the Ochsner Clinic Foundation in Baton Rouge, La.
When a fetus is undernourished, it adapts by diverting nutrients to areas such as the brain that are crucial for its survival at that particular stage of development, Blake says.
This might help the fetus survive until birth, but it can mean problems later in life, Blake explains. The adaptations could permanently change the functioning of organs and metabolism.
"We are not suggesting that scanning fetuses has any use as a screening method for people with high blood pressure," Blake says. "What we are saying is that people who were exposed to an adverse environment in the womb may be at risk of high blood pressure that is not due to the known, conventional risk factors for blood pressure such as obesity or salt intake."
It's important to note that none of the children had hypertension; they just had a small uptick in blood pressure at age 6, Dauterive says. Whether that has any link to hypertension in adulthood is not yet known, he adds.
"Those kids have to be followed into adulthood to see if they develop a higher rate of hypertension," Dauterive says. "Are you seeing more renal disease, more strokes, more complications of hypertension? Or is it just an isolated, insignificant finding?"
What To Do
To read more about how to take care of yourself during pregnancy, check out the U.S. Department of Health and Human Services' Bright Futures or the National Women's Health Information Center.
