Key points about blood pressure in newborn babies
- blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps blood around the body
- normal blood pressure varies between pēpi and changes after birth
- a health professional may measure blood pressure using a small cuff or an arterial line
- your baby’s healthcare team will consider blood pressure readings alongside your baby’s overall condition
- some pēpi need fluids or medicines to support their blood pressure
About blood pressure
Blood pressure is the pressure of blood pushing against the walls of the arteries.
Blood pressure is affected by:
- how well your baby’s heart pumps
- the amount of blood and fluid in their body
- how narrow or relaxed their blood vessels are
Maintaining a healthy blood pressure helps provide steady blood flow to your baby’s brain, kidneys and other organs.
Understanding blood pressure readings
Blood pressure is measured in millimetres of mercury (mmHg). It’s usually recorded as 2 numbers:
- Systolic pressure is the pressure when the heart pumps blood out.
- Diastolic pressure is the pressure when the heart rests between beats.
You may hear health professionals talk about mean arterial pressure (MAP). This is the average pressure in the arteries during 1 heartbeat.
Normal blood pressure in newborn pēpi varies. It depends on their gestational age, birth weight and age after birth. Gestational age is the number of weeks of pregnancy when your baby was born.
Low blood pressure in newborn babies
Low blood pressure is common in very premature pēpi. It can happen for several reasons, including:
- transitioning from being inside the womb to outside
- infection
- loss of blood or fluid
- problems affecting the heart or lungs
Sometimes your baby may need medicine given into the vein for a short time. This can help support your baby's heart and blood pressure.
If your baby has lost blood or fluid, health professionals may give them fluids into the vein. This can help improve their blood volume.
High blood pressure readings in newborn babies
A blood pressure reading may be high if your baby is in pain, moving or unsettled during the measurement.
Rarely, an illness or health condition can cause high blood pressure. Your baby may need further tests if their blood pressure remains high.
Measuring your baby’s blood pressure
The healthcare team may measure your baby’s blood pressure:
- using a small cuff around your baby’s arm or leg or
- through a small tube called an arterial line - this goes into an artery in the umbilical cord, hand or foot
The healthcare team will keep checking your baby’s blood pressure. They will do this until the readings are stable and your baby is getting better.
References
Adapted from the leaflet: 'Blood Pressure. Neonatal Services. Matatiki, Child & Youth Health, Waitaha Canterbury'.
