Newborn tests

by | Jun 11, 2020

There are a range of tests that a doctor may perform to ensure the wellbeing of your baby. Paediatrician Dr Enrico Maraschin takes us through them. Tests on newborns begin a while before the baby is born – during the initial stages of pregnancy. Once baby is born, further tests will be recommended.Together these tests provide information to your healthcare provider and ensure that your bundle of joy is properly cared for. Let’s consider the most important tests.

During the pregnancy

  1. Blood type: A test to establish mommy’s blood type is necessary so that if an incompatability exists between the mother’s blood group and that of her baby, medical intervention can be taken. A negative blood group (Rhesus factor) may lead to incompatability with a foetus in the second or subsequent pregnancies. If there is such an incompatibility, the mother may develop antibodies causing damage to the foetus or loss of the pregnancy. Knowing this ahead of time will give the doctor the opportunity to administer medication to prevent the mother from developing antibodies.
  2. Genetic Abnormalities: A mother’s blood can be tested to screen for genetic abnormalities of the foetus. This is a major step forward as potential genetic abnormalities can be identified early on.
  3. Ultrasound:The obstetrician will also perform ultrasound examinations on the foetus to make sure that the foetus is developing well. Through this process, your baby will have been checked extensively before he or she is even born.
  4. Blood test: To screen the mother for her general health and for possible infections that could affect the pregnancy.


At birth:

  1. Thyroid function (TSH): Blood is taken from the cord to conduct a thyroid function test. Thyroid is an extremely important hormone, which regulates both the growth and development of the baby. Unfortunately problems related to thyroid can only be detected clinically a lot later in life. This means that without the thyroid test, damage may already have been done to an individual with thyroid problems. For this reason, tests are performed immediately at birth so that intervention can be instituted and growth and developmental delays can be stopped.
  2. Blood group: The baby’s blood group is established from the cord blood. The Rhesus incompatability has been discussed above. ABO incompatability may also result in severe jaundice. The doctor would be alerted to this if the mom is O but her baby is A, B or AB.
  3. Paediatric checks: Following the birth a paediatrician will examine the baby as follows:
  • Systems: The baby is examined head to toe, and a deeper examination of the systems such as the heart and lungs is performed. Should abnormalities be detected during the examination, further investigations would be required. These may include a referral to sub-specialities within paediatrics, blood investigations or radiological investigations of the baby.
  • Congenital dislocation of the hips: This condition requires treatment soon after birth since delayed treatment can lead to a lifetime of hip problems. If the paediatrician is concerned about the hips an ultrasound will be performed. Referral to a paediatric orthopaedic surgeon may be necessary. The paediatrician will also check for abnormalities of other bones. This will include examination to exclude clubfoot or abnormalities of the spinal column. Any of these abnormalities will also require a referral to a paediatric orthopaedic surgeon for further treatment.
  • Heart: Another condition that needs to be excluded at birth is a condition called coarctation of the aorta. With this condition, there is an abnormality of the aorta which does not allow enough blood supply to the lower body. The paediatrician will examine the pulses in the groin to determine whether adequate blood supply is reaching the lower limbs. An oximeter checks the oxygen levels in the upper and lower parts of the body, which may also help identify this condition.

Other recommended tests

  1. Eyes and ears: A lot of learning that happens in humans is heavily reliant on the fact that your baby can hear and see well.
  • With technological advancement, we are now able to test a baby’s hearing at birth. An audiologist will place a probe in the outer ear of your baby. The probe transmits a sound which echoes in the inner ear. Hearing abnormalities of this nature may be due to fluid behind the eardrums following the delivery, or there can be more permanent abnormalities to the hearing mechanisms. Abnormal findings of these tests may require a referral to an ear nose and throat specialist for more indepth evaluation.
  • Your paediatrician should examine the eyes to exclude possible cataracts. Should abnormalities be detected, a referral to an ophthalmologist will be necessary.
  • There are tests for eyesight that are available from six months of age. This test has a very good pick up rate for most abnormalities of the eyes.
  1. Metabolic Screen: There is an optional test available called the newborn screen or the metabolic screen. This test is designed to detect up to 24 inherited disorders. Inherited disorders have the ability to harm your baby before signs of the disorder are even visible. Early screening alerts the paediatrician to the presence of an abnormality and action can be taken quickly if necessary. Should the parents opt to perform this test, a heel prick is performed at 48 to 72 hours of life. This screening test does not necessarily confirm the presence of one of these rare disorders. Should the screening test come back positive, more directed and more specific tests are often required to confirm such diagnosis.
  2. Bilirubin: This test checks for jaundice levels. A baby with jaundice becomes excessively sleepy and struggles to feed. Babies with high jaundice levels may require phototherapy. In severe cases they may require an exchange blood transfusion. Your paediatrician may ask for the jaundice level to be checked even once your baby has gone home. Phototherapy can be done at home. A nursing sister will visit baby at home, set up the lights and monitor the levels.

Neonatal ICU

The tests mentioned above would be performed on infants that are normal at birth. Should your baby be admitted to Neonatal ICU (NICU) for further treatment, additional tests may be performed.

  1. Blood test: This will be done to exclude infection.
  2. Chest X-ray: To exclude a chest infection.
  3. Cranial ultrasound: Premature babies are at risk for brain bleeds. A cranial ultrasound may be performed to exclude a bleed. The presence of a bleed would require follow-up, but your paediatrician will guide you on this process.

The goal of paediatricians – and the tests we run – is always to keep babies healthy and keep them with their parents. Technological advances in testing have been explosive, and the outcome of both normal newborns and pre-mature babies gets better every year.

Most paediatricians have a “when in doubt, sort it out” approach, because the unfortunate flipside to this saying is that “if you wait, it could be too late” – which is why testing of this nature is so important to ensure we can keep your baby safe and healthy.