The $4 Test That Could Save Your Baby's Life

newborn and mother
Ariel Skelley/Getty Images

What takes four minutes and costs four dollars and saved the life of one baby in Washington?

A simple oxygen monitoring test. 

The test called pulse oximetry, is one that you may be familiar with, as it's often included anytime you get a check-up at the doctor's office. A little machine goes on your finger and measures the oxygen saturation in your skin, giving care givers a picture of how well your body is using oxygen as it's supposed to.


While I worked as a labor and delivery nurse, the hospital instituted a policy that pulse oximetry readings had to be taken on every newborn within the first 24 hours of life. The test was so easy to do with a small, flexible monitor that wrapped around a baby's heel, wrist, or sometimes even on their ear. It almost looks like a band-aid and is completely painless for the baby—they often wouldn't even wake up when the monitor was applied.

Why The Test Is Needed

With newborns, it can sometimes take some time for their cardiovascular and respiratory systems to transition into working outside of the womb, so oxygen readings with the oxygen monitor are different from those of older babies or adults. For example, a normal oxygen level for a baby at one minute post-birth is different than a baby at 10 minutes of life. And babies born by C-section also have lower initial oxygen saturation levels.

Overall, it takes about 5 minutes for a newborn to a normal oxygen saturation rate breathing room air. 

Because the cardiovascular and respiratory system (the heart and breathing) of a newborn can be transitory, meaning it can take some time to kick in, it also means that sometimes a baby can appear perfectly healthy, but actually have an undiagnosed heart problem.

It's almost as if the newborn's body compensates for that first day of birth as the systems regulate and then a problem can be detected only when the baby is in severe respiratory distress. One study found that oxygen saturation can vary widely--anywhere from under 60% to an average of 98.3%--in the first 24 hours of life, numbers that actually fluctuate during the first month of life as well, as many newborns actually breathe irregularly. (Also totally normal.)

The wide fluctuations are why taking a pulse oximetry reading early after birth is so important—it can detect a problem before it's too late or before a baby will need to be resuscitated. Not to mention, if the newborn's poor little body is burning up critical energy and calories simply trying to breathe, it won't be able to do other vital functions such as maintain temperature or eat, and before you know it, one problems has turned into many critical health problems.

How The Test Saved One Baby's Life

Baby Conrado, who was profiled in a local Washington newspaper, was just such a baby. Born at home and appearing totally healthy and normal in every regards, he passed all of the tests that his midwife performed on him after his mother's home birth.

Except his pulse oximetry test done after he was 24 hours old.

He failed that test and spent the next 23 days at Seattle Hospital where he underwent massive heart surgery to correct a previously undetected heart abnormality.

The American Heart Association notes that 9 in 1,000 babies are born every year with a congenital heart defect. (Shockingly, the AHA says that heart defects are the #1 cause of infant death in the United States!) They promote the use of the pulse oximmeter for those babies who may be at risk at birth, which is why more hospitals and states are making pulse oximetry law.

The takeaway from all of this, is of course, to know exactly what kind of testing your baby will have in the hospital and to be aware of the some of the signs and symptoms of respiratory distress in your baby, including a baby that seems overly tired, won't eat, is having labored breathing with nasal flaring or looks like his chest is going "inwards" or is blue in color.


And of course, if you are planning a home birth or an out-of-hospital birth, to check that the facility or midwife who will be caring for your baby will have pulse oximetry equipment available. 


Rabi YYee WChen SYSinghal N. (2006, May). Oxygen saturation trends immediately after birth. Journal of Pediatrics, 148(5):590-4. Accessed online November 3, 2015: 

L O'BrienV StebbensC PoetsE Heycock, and  D Southall. (2000, July). Oxygen saturation during the first 24 hours of life. Arch Dis Child Fetal Neonatal Ed, 83(1): F35–F38. Accessed online November 3, 2015: 

Hermansen, C. L. & Lorah, K.N. (2007, October). Respiratory Distress in the Newborn. American Family Physician, 76(7):987-994. Accessed online November 3, 2015: 

The American Heart Association. Accessed online November 3, 2015: 

Continue Reading