One of the major objectives of fetal scan is to assess the structural normalcy of the fetus and to identify the nature and prognosis of any fetal defects detectable on ultrasonography if any.
Not at all. In fact it is the proven safest mode of evaluating the baby and the pregnancy. It
actually works on the principle of vibration of crystals producing electromagnetic waves
which are not at all harmful to the baby or to the mother.
- Basically, three major scans are needed during the entire pregnancy:
First trimester screening at 3 months
- Anomaly scan / TIFFA at 5 month
- Interval growth scan at 8 months
However, there may be additional scans included depending on various factors affecting the
baby as well as maternal illness
Yes, definitely. The fetal scans at all stages of your pregnancy will be able to detect an
average estimated fetal weight and growth of your baby. We also keep a track of the growth
velocity that is the speed with which your baby is growing over a period of time on growth
Normally humans have 46 chromosomes in their cells. Instead, if there 47 chromosomes
(due a extra copy of 21 st chromosome), Down syndrome occurs. These children may have
variable degree of intellectual handicap, problems of heart, intestine, and other health
The only certain way to know if the fetus has Down syndrome or not is to study the fetus’s
chromosome. For this, a direct test of the baby’s fluid (amniocentesis) or placenta (chorionic
villus sampling) needs to be done. Only for those fetus that have a high chance of having
Down syndrome, this test is recommended
The condition called “Down Syndrome” occurs in about 1 in 600 births. The FTS test
attempts to predict this condition along with ruling out major structural abnormalities and
prediction of preeclampsia in the ongoing pregnancy.
The first component is a detailed ultrasound examination of the fetus looking for a) Length
of the fetus (Crown Rump Length) (b) Fluid behind the baby’s neck (c) Presence or absence
of baby’s nose bone and (d) baby’s heart beat rate. Apart from this information, the scan
also looks in detail about the baby’s activity and organ formation according to the age of the
fetus. The second component is a blood test (usually a finger-tip prick; sometimes blood
drawn from a vein) to measure certain hormones produced by the placenta. Using
information from both components, the computer programme calculates the chance of
being affected with Down syndrome based on the mother’s age and weight.
The result is usually given as a chance calculation (also known as risk calculation). For
example, if the test result says Final Risk 1: 850, this means that out of 850 pregnancies that
have the same scan measurements and blood test measurements, there is going to be 1
fetus with Down syndrome (i.e this fetus has a 1 in 850 chance of being affected). In medical
practice, we would recommend going ahead with direct testing when the chance is greater
than 1 in 250 (for example, when the final risk is 1 in 150 or 1 in 75 etc…)
The appropriate time to undertake FTS is when the baby’s length (CRL) is between 45 and 84
mm; this usually corresponds to 11 weeks and 14 weeks from the last menstrual period
As a result of 10 – 15 years of research in fetal medicine, this strategy (of all women
undergoing FTS, and in those with final chance of 1 in 250 or greater performing amnio /
CVS) is shown to detect about 85 – 90% of all Down syndrome fetuses.
Also, you should be aware that not all fetuses that get a score of greater than 1 in 250 will
have Down syndrome. In fact, among fetuses that have a risk (chance ) of greater than 1 in
250, only 2 – 3% will have Down syndrome
The First Trimester Screening Test (FTS) is accurate when performed between fetal length of
45 and 84 mm, that roughly corresponds to 11 weeks and 14 weeks. If for any reason you
had missed the window to undergo the test and would still like to be screened for Down
Syndrome, the next best option is to go for an ‘early pregnancy anomaly scan’ followed by
the Quadruple Screening Test (QST). Although not as accurate as the FTS, the QST along
with a detailed scan is sufficient to reassure most pregnancies.
The NIPT is advised as a second step test in very select circumstances rather than as the first
line due to two reasons: a prohibitively high cost and the need for a high-quality scan to
exclude major fetal defects. At FETOSCAN, we offer NIPT in select situations only after a
detailed counselling regarding the pros and cons of the NIPT compared to other options that
would be applicable in that particular individual.
No, it is not mandatory that you should undergo Down Syndrome screening. You can
understand about Down syndrome and the detection tests available, and then you can
decide if you want to undergo the screening test.
Remember screening tests are indirect. A screen positive result does not mean the baby is
affected. A screen positive test only indicates that a further confirmatory test may be
Another important thing to remember is that no screening test can detect all cases of Down
syndrome. This means that when the indirect test says screen negative, it says that the
chance of the baby having Down syndrome is very low.
In short, a properly conducted FTS or a QST along with a normal target scan can reliably
reassure most women. However, the choice of undergoing the screening test is always
Nuchal translucency [NT] is the ultrasound appearance of the fluid behind a baby’s neck.
This fluid appearance is present in all fetuses.
During the first trimester screening test, we measure the thickness of this fluid. We follow a
very strict procedure in measuring this thickness because, firstly it is a tiny measurement [in
millimetre] and secondly, even small changes can have big impact in the final result.
Using the nuchal translucency thickness, we calculate the chance of the baby having Down
Syndrome. The lab will combine the value of the NT along with the blood levels of two
hormones produced by the baby’s placenta and based on the mother’s age will give a value.
This value represents the chance of Down syndrome.
It is important to note that even when the NT is increased, most babies will be normal.
There is no need to panic. If the NT is increased, a step-by-step evaluation of the baby will
- You should undergo the & quot ;first trimester screening & quot; or commonly referred to as FTS, between
11 weeks and 13 weeks – 6 days, when the baby's length (denoted by CRL, crown rump
length) is between 45mm and 84mm.
There are three broad aspects of FTS:
Firstly, after a thorough analysis of your medical, previous pregnancy, family and other
relevant history, and your blood pressure measurements, we study what are the issues we
should (your obstetrician and our team) be looking for during your entire pregnancy
- Secondly, a detailed targeted ultrasound examination of the baby is done: at the end of
this evaluation, we would have ruled out most of the lethal conditions, and about 60% of
- Thirdly, we will evaluate the baby for chance of Down syndrome: for this we measure the
baby's nuchal translucency (neck fluid thickness), see if the nasal bone is bright, measure
the levels of two hormones produced by the baby's placenta [hCG and PAPP-A]: together
these measurements along with your age will be used to calculate the chance of baby
having Down syndrome
Fetal echocardiography is generally performed between 22-24 weeks of pregnancy. It is a
detailed evaluation of fetal heart- structurally as well as functionally. We use various cardiac
biometric measurements, dopplers as well as a thorough imaging of the heart as per
standard and advanced protocols to rule out any detectable ultrasound cardiac defects in
the fetus. It is specifically necessary for special cases like maternal diabetes, previous child
with cardiac problem, family history of cardiac illness, maternal alloimmune system
abnormalities or any suspicious ultrasound abnormalities detected previously in the ongoing