General information about oxygen saturation measurements shortly after for newborns

Screening through Oxygen measurements – positive study results!

In the period July 2015 till December 2016 the POLAR trial was performed in all hospitals and almost all midwifery practices in the regions Leiden, Haarlem/Hoofddorp, Amsterdam, Alkmaar and Purmerend.

Aim of this trial was to determine if by performing oxygen measurements (saturation measurements) after birth we could, in an early stage, detect critical congenital heart defects that were not detected at the 20 weeks ultrasound.

Almost 24.000 newborns participated in this trial. Final results show that oxygen measurements are able to detect congenital heart defects as well as other illness. To change national guidelines to make this screening ‘standard care’, the Dutch government needs to decide on new policy first.

However, your obstetric caretaker has decided to continue performing these oxygen measurements in the period of waiting for this new policy.

In this brochure you can read more information about this extra screening that will be offered to you baby.

Background information

About 180,000 children are born in the Netherlands each year. Approximately 1,250 have a heart defect of which 250 are life threatening. Fortunately, most congenital heart defects are well treatable. This generally requires heart surgery.

Not all heart defects are detected

A 20-week ultrasound scan is offered during pregnancy. This detects about 70% of all heart defects in our region. So approximately 30% of congenital heart defects is not detected at the 20-weeks ultrasound. Shortly after birth, a baby may not show signs of the heart defect yet, which means that some are missed or diagnosed to late.

Detection of heart defects

A heart defect may cause a decrease in blood oxygen level (saturation). The baby often does not show any signs of this shortly after the birth, but this can be easily detected by measuring the oxygen level in the blood. This is done using an oxygen measuring device (pulse oximeter). Pulse oximeters are already being used in other countries to detect heart defects. In these countries this happens in the hospitals. In the Netherlands, most children are at home within one day after birth or have been born at home.

Detecting other disorders

Besides congenital heart defects, there are other disorders which may cause low blood oxygen levels. Babies with lung problems or an infection also commonly have a lower blood oxygen level. These disorders can be discovered earlier as well by measuring the oxygen level.

Frequently asked questions (FAQ)

What is a Pulse oximeter? An pulse oximeter is a device that measures the oxygen level in the blood. The device is wrapped around child’s wrist and foot. It uses light to measure the oxygen level in the small blood vessels. This is not painful or uncomfortable for your baby.

Who will perform the measurement? If your baby is born in hospital, the oxygen measurement will be done by a doctor, midwife or nurse. If you deliver your baby at home, the midwife will perform the measurement.

How will the screening be performed? Approximately one hour after birth, the oxygen level will be measured on your baby’s right wrist and on one of its feet. Chances are that the measurements are perfectly normal. If they are, the measurements will be repeated on day 2 or day 3 of your baby’s life just to be sure. The results are not normal if the oxygen level is too low.

What happens if the results are not normal? An abnormal result does not necessarily mean that your baby has a heart defect or another disorder. The measurement might be wrong, for example if the hands or feet of the baby are too cold, or the baby is moving a lot, or there might be other reasons why the oxygen level is too low. Your caretaker will probably repeat the measurement on a later moment or, if he /she thinks that is appropriate, will consult a paediatrician to discuss what is best to do.

What is additional to or different from usual? Normally, the midwife will examine the baby after birth to see if there are any abnormalities. The oxygen measurements taken during this standard examination are extra. Screening blood oxygen levels is already standard practice at some hospitals and midwifery practices.

Is it safe? The oxygen measurement is not dangerous for your baby. There are no known risks. Oxygen measurements have already been taken for years to monitor sick newborns admitted to hospital.

Does the test offer 100% confidence? Your baby’s oxygen level may be abnormal, but the follow-up examination may not detect a heart defect. There is also a small chance that the saturation measurement is normal while your baby does have a congenital heart defect. Normal results do not give a 100% guarantee that your baby’s heart is completely normal. You should contact your General Practitioner if you are in any doubt about your child’s health.

Pulse oximeter
sensor on a baby’s foot

Advantages and disadvantages of the screening


  • Symptoms of a heart defect are often not evident immediately after birth. This means that heart defects are sometimes discovered too late. The oxygen measurement may allow some heart defects and other serious disorders to be discovered sooner. This may allow treatment to be given sooner, before your baby becomes seriously ill.
  • Other disorders associated with low oxygen levels may be discovered sooner by taking this measurement. Lung problems and infections can then be detected before your baby’s health deteriorates.


  • There is a small chance that the oxygen level is too low, even though your baby does not have a heart defect (false positive result). This may make parents unnecessarily concerned.
  • An abnormal result requires extra tests in the hospital to determine if the baby is ill which can cause extra hospital visits or -stays for parents and their baby shortly after giving birth.

More information

If you have any questions after reading this information, feel free to ask your midwife or doctor.
At any time, without giving any reason, you can decide for your baby not to participate in this extra screening.

Special thanks to:
Dr. I.C. Narayen – researcher POLAR-studie