Health Screening for my Babe

Pregnancy is an amazing thing. Inside your body is a growing foetus that will, in months, come into this world. This process is incredible and usually straight forward. However, there are times when things may go wrong and your baby may not develop the way he/she should.

1 Understanding Screening

Babies can be abnormally formed or be affected by poor development while in the womb of the mother. With modern science, assessing your unborn child’s health is no longer a dream.

Foetal diagnostics allow doctors to screen your unborn child for potential health problems and physical defects. Parents are thus better able to cope with the potential stress involved. Your doctor can also better manage your pregnancy to ensure that you can have a smooth delivery.

According to Dr Tony Tan, Specialist in Obstetrics and Gynaecology, Raffles Women’s Centre, about two to five per cent of babies are born with some type of birth defect. “This may be due to chromosomal abnormality, genetic disease or structural abnormality in the baby.”

Women of all ages, and not just those aged 35 and above, should consider screening for ease of mind as many abnormalities in the babies are random events and may not be easily identified by factors such as age or family history.

“All pregnant mothers, to a certain extent, must receive some basic form of foetal screening,” advised Dr Chow Kah Kiong, Specialist in Obstetrics and Gynaecology, Raffles Women’s Centre. “The most usual one is a routine blood test. The next almost universal test is an early ultrasonogaphy on the foetus.”

However, depending on the risk factors in the pregnancy, more tests may benecessary to ensure that the unborn child is of good health and not affected.

Foetal screening is important as doctors can detect abnormalities in the unborn child early. If there is a defect that is incompatible with life, the parents can be counselled. Early detection also allows for safe termination of the pregnancy.

Certain abnormalities necessitate the baby to be borne by a certain method (like induction for early labour or Caesarean section). Sometimes, babies with certain abnormalities require immediate specialised medical attention at birth and this could be arranged in anticipation if the abnormalities
are detected during foetal screening.

2 Tests to set your mind at ease

Foetal screening can be conducted during the first, second and third trimester. We speak to Dr Tony Tan who has special clinical interests in foetal medicine and therapy on the various types
of screening and their purpose.

What is the first trimester screening about
and who needs it?

The First Trimester Screening combines historical data, high resolution ultrasound scans with the mother’s blood. It is conducted earlier than most other prenatal screening tests, between the 11 to 13 weeks of your pregnancy. As a routine prenatal screening test, it is safe and poses no risk of miscarriage or other pregnancy complications.

It has, over the years, developed into an improved version as it screens for common chromosomal abnormalities such as Down syndrome, early structural abnormalities, and the risk of early preeclampsia (a condition which manifests as high blood pressure with proteins in the urine during pregnancy that requires delivery before 34 weeks).

I recommend this test to all pregnant women regardless of age, as it is now recognised as the best screening test for Down syndrome. It is better than screening for Down syndrome just by maternal age alone. Knowing the risk of severe pre-eclampsia early in pregnancy also allows the identification of those at high risk to benefit from the use of medications such as calcium
supplementation and low dose aspirin early in pregnancy. This may reduce the risk of pre-eclampsia.

Our clinic has a very good performance record in the First Trimester Screen, with a very high detection rate of Down syndrome.

When would the second trimester
screening need to take place and what
is it for?

In the second trimester, the foetus is screened around 20 weeks for common structural abnormalities that can be detected by ultrasound, placental localisation and cervical length. This is
an important scan as it allows parents to be reassured that there are no structural abnormalities in the majority of cases. It also allows the identification of structural abnormalities that may need to be treated during pregnancy or soon after delivery.

If the placenta was low-lying, the obstetrician would have to take note of symptoms like vaginal bleeding and check the location of the placenta later in the third trimester to determine whether a
Caesarean section is required for delivery. A short cervix at 20 weeks increases the risk of premature delivery before 33 weeks. For those with a short cervix, your doctor may treat you with progesterone to reduce the risk of premature delivery.

What is the third trimester screening about?
Is it necessary?

In the third trimester, the foetus may be screened for growth disorders. In five per cent of cases, the foetus is growing below the normal range. Such foetuses should be monitored closely so as to determine the best time for delivering the foetus. A 3D or 4D scan, purely for bonding between
parents and the foetus, may also be performed at this time if you wish. HN