Measuring Blood Pressure in Children

Why It's Important and Special Considerations

Pediatric's office nurse with patients
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There's been a recent upward trend in the number of children with high blood pressure (hypertension). Unfortunately, cases often go undiagnosed and untreated, leading many experts to believe that children's blood pressure isn't being measured often enough. This is especially concerning because kids with this condition usually don't have symptoms, meaning a doctor might have no other reason to measure blood pressure in a child than it simply being an important matter of routine.

Up to 19 percent of American boys and 12 percent of American girls have high blood pressure, according to data from the National Health and Nutrition Examination Survey (NHANES). Prevalence is higher in older children, as well as Hispanic and African-American children. And when not caught early, hypertension in a child can persist, leading to problems in adulthood, such as heart disease and organ damage.

It is important for pediatricians to take the time to screen blood pressure and to evaluate for its potential causes.

Blood Pressure Screening in Children

Children should have routine blood pressure (BP) measurements starting at three years of age as part of annual physical examinations.

Blood pressure may be checked more frequently in children who:

  • Are significantly overweight or underweight
  • Have stayed in the intensive care unit (ICU) for any amount of time after birth
  • Have/ have had any known heart, lung, or circulatory problems
  • Have experienced any complications or difficulties before, during, or shortly after birth

The blood pressure readings taken at the doctor’s office will become a part of your child’s medical record and will allow the doctor to track blood pressure trends over time in order to more easily detect potential problems.

Blood pressure screening involves two separate measures: systolic blood pressure (BP) and diastolic blood pressure (BP). Systolic BP is the highest pressure of the arteries as the heart pumps out blood for circulation throughout the bod, while diastolic BP is lower pressure in the arteries when the heart relaxes between beats. If either one or both measures are above the range for people of the same age and gender, it is called hypertension. 

It is difficult to diagnose high blood pressure in children because theirs is affected by their age, sex, height and weight. These changes are why it makes sense for children to be screened at least yearly.

If your child’s blood pressure is found to be high at a doctor visit, the pediatrician will ask you to bring the child back a week or two later to see if readings are consistent. If you children’s readings are consistently high, he or she will need additional testing to determine the cause and any potential complications, such as organ damage.

Parents should ask if blood pressure was checked at each child well visit and, if so, what the reading was and if it is normal or concerning.

Proper Technique and Practice

The proper technique for taking a blood pressure reading in children is the same as for measuring blood pressure in adults, and it's essential for accuracy. The child will need be still and calm for an accurate reading. Crying, in particular, can increase blood pressure.

During this procedure, parents and other caregivers should watch the health practitioner to ensure that the following best practices are followed:

  • Cuff size: Since an incorrectly sized cuff can produce falsely high or falsely low readings, make sure the provider takes the time to choose the correct one. The proper cuff size for your child depends on the size of their arm and is usually the largest cuff that fits while still leaving room for the head of the stethoscope.
  • Timing: Recent physical activity can skew an otherwise good reading. Therefore, wait until your child has been relatively calm for at least five minutes before you begin. During the procedure, children should sit down and try to relax. Taking a couple of deep breaths together may help calm an anxious kid.
  • Repetition: Your child's healthcare practitioner should take at least two separate readings during each visit. While these readings must be taken at least two minutes apart, taking readings at the beginning and end of the appointment may provide more accurate results.
  • Consistency: For the most consistent results, medical professionals should use the gold standard for measuring blood pressure—the "old fashioned" cuff and stethoscope combination. If an automated device detects a high reading the first time, ask the doctor to switch to this method for the second reading.

    The “mm Hg” abbreviation in BP readings means millimeters of mercury. Mercury in blood pressure gauges makes them more accurate, which is why these remain the gold standard in measuring blood pressure.

    Normal Ranges for Children

    Normal blood pressure ranges are continuously changing in children. Blood pressure is lowest in infants and will continue to increase slowly until about age 10. Blood pressure is also higher in boys than in girls of the same age group. Normal blood pressure values in children will also increase with body size. 

    The National High Blood Pressure Education Program (NHBPEP) has published definitions of prehypertension (elevated BP) and hypertension (high BP) in children:

    • Prehypertension: BP reading equal to or greater than 120/80
    • Stage 1 hypertension: BP reading of 120/80 to 120 to 129 mm Hg systolic and less than 80 mm Hg
    • Stage 2 hypertension: BP reading of 130/80 mm Hg or higher

    While the NHBPEP definitions vary slightly based on sex, age, and height, the differences are actually quite small. This is because pediatricians consider blood pressure of 120/80 mg Hg in children as prehypertension while anything greater means a child has hypertension.

    In addition to the NHBPEP’s definitions, the National Institutes of Health (NIH) offers reference tables of normal and abnormal BP ranges for children. For example, a diagnosis of high blood pressure can be made in a child if his or her blood pressure is higher than 90 percent of children of the same gender, age, and size. 

    A Word From Verywell

    Family history of high blood pressure puts a child at risk for the condition. Parents should let their child’s pediatrician know of any family history of hypertension. Obesity and some medical conditions, like kidney disease, endocrine disorders, and heart problems, further increase a child’s risk. By being aware of your child’s risk factors for high BP, you play an important part in reducing the risk and identifying problems early on.

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