High blood pressure (hypertension) is an increase in the force of blood against the arteries in the body. This article focuses on high blood pressure in infants.

Blood pressure measures how hard the heart is working, and how healthy the arteries are. There are two numbers in each blood pressure measurement:

• The first (top) number is the systolic blood pressure, which measures the force of blood released when the heart beats.
• The second (bottom) number is the diastolic pressure, which measures the pressure in the arteries when the heart is at rest.

Blood pressure measurements are written this way: 120/80.

Several factors affect blood pressure, including:

• Hormones
• The health of the heart and blood vessels
• The health of the kidneys

High blood pressure in infants is usually the result of kidney or heart disease that is present at birth (congenital). In newborn babies, high blood pressure can also result from a blood clot in a kidney blood vessel, a complication of having an umbilical catheter.

Other causes of high blood pressure in infants may include:

• Certain medications
• Exposure to illegal drugs such as cocaine
• Certain tumors
• Inherited conditions (problems that run in families)
• Thyroid problems

Blood pressure rises as the baby grows. The average blood pressure in a newborn is 64/41. The average blood pressure in a child ages 1 month - 2 years is 95/58. Some variations in these numbers are normal and are not cause for concern.