As per the findings of the WHO nearly 24,000 newborns die every year worldwide due to congenital disabilities. One should never underestimate these birth defects as they can contribute to permanent and irreversible disabilities. Such long-term health problems have a major impact on parents, societies, and healthcare systems. In order to prevent such disasters from happening, an anomaly scan is highly recommended during the second trimester of pregnancy. The anomaly scan detects congenital disabilities in the developing fetus and the results help decide the next course of action, considering the welfare of the baby and the expecting mother. Anderson Diagnostics and Labs, the best anomaly scan centre offers accurate and affordable anomaly scans in Chennai. Let us learn more about anomaly scan in the article below to know its importance.
Everything You Need to Know About Anomaly Scan
The fetal anomaly scan is also referred to as TIFFA, which means Targeted Imaging For Fetal Anomalies. It is a mid-pregnancy scan performed between the 18th and 21st week with an ultrasound. It determines the presence of any malformation and assesses the physical development of the fetus. An anomaly scan is performed approximately during the 20th week as anytime before that, it is impossible to detect the baby's organs through an ultrasound scan. The reasons why an expecting mother should perform an anomaly scan are:
- To reassure that the fetus is growing normally.
- To detect defects in the heart and conditions like spina bifida.
- To determine the gestational age of the pregnancy.
- To identify the number of fetuses,and in case of twin pregnancies, to find out whether they are identical.
- To find out subtle markers that indicate chromosome issues.
A sonographer will be ready to provide the entire details about the development of the fetus after an anomaly scan unless the parents request them not to share anything in specific.
Role of a Sonographer in an Anomaly Scan
The sonographer will check the heartbeat of the baby and show the parents the different parts of the baby's body. You will not be able to determine the baby's sex by looking at the anomaly scan as the sonographer will be analysing the cross-sectional image of the fetus. In many countries, revealing the sex of the baby is considered illegal. The technician will determine the baby's growth by measuring the body parts. Besides these, the other default checks which every sonographer performs will be:
- Cleft lip and palate while checking the baby's face.
- Structure and shape of the baby's brain and head.
- Length of the baby's spine, alignment of all the bones and whether the skin covers the back of the spine.
- Structure and location of the heart along with its rhythmic pattern.
- Wall of the baby's abdomen to see whether it covers the internal organs in the front.
- Presence of bladder, stomach and two kidneys.
- Extremity parts like legs, hands, arms, feet, toes, and fingers.
- Location of the placenta and the amount of amniotic fluid around the baby.
- Length of the cervix.
The measurement of the baby's head circumference (HC), abdominal circumference (AC), and femur bone length (FL) must match the expected delivery date. These measurements ensure the baby is growing at a desired rate within the expected limits. But you should understand that these measurements are basic determination during the early stages of pregnancy to calculate the due date.
Also Read: An Overview of Ovarian Cysts & Imaging Tests
Conditions Which Get Detected Through an Anomaly Scan
The sonographer will be able to detect a few of the medical conditions through the anomaly scan. A few of the health conditions are easy to spot, while a few are not visible in the scan. There are a few problems that can be resolved and treated after birth. In such cases, the doctors will notify the hospital in advance to ensure that the baby receives proper care immediately after birth. But rare disorders or severe abnormalities may be life-threatening. The list of medical conditions and the chances of them getting detected through an anomaly scan is mentioned below. Though the percentage values are not 100 percent accurate, they will give you information about the chance of detection.
- Congenital heart diseases, including the defects in the heart chambers, vessels, or valves – 50%
- A cleft lip, which is a split in the upper lip in between the nose and the mouth – 75%
- Spina bifida that affects the spinal cord - 90%
- Anencephaly, a condition where the parts of the brain and skull are not completely formed – 98%
- Gastroschisis, a defect in the walls of the abdomen wherein the belly button is not fully developed, and the intestines protrude outside the baby's tummy – 98%
- Exomphalos, another abdominal wall defect where the liver and bowel protrude into the umbilical cord – 80%
- Congenital diaphragmatic hernia, where there is a hole in the muscle that separates the abdomen and chest – 60%
- Bilateral renal agenesis, a condition where both the kidneys are not completely formed – 84%
- Severe skeletal dysplasia, an extreme bone development problem because of which the lungs and chest do not develop fully – 60%
Possibilities of Detecting Down Syndrome Through Anomaly Scan
An anomaly scan is considered very precise, but it is impossible to diagnose congenital abnormalities thoroughly. In the case of Down syndrome, the chance of detection with an anomaly scan ranges from 50% to 60%. Most cases appear normal in an ultrasound scan. Amniocentesis will be able to give definite information about Down syndrome. The first-trimester screening, also called the FTS test, is the best option to identify down syndrome with greater detection rates.
Chromosomal Abnormalities Identified Through an Anomaly Scan
There are certain chromosomal abnormalities detected through an anomaly scan with a probability of 90% to 95%. They are:
- Patau's Syndrome (Trisomy 13) is caused by an extra chromosome 13.
- Edwards' syndrome (Trisomy 18) is caused by an extra chromosome 18.
- Turner syndrome is a condition in which the baby has 45 chromosomes as they lack one X chromosome.
- Klinefelter Syndrome is a condition in which the baby has extra sex chromosomes. These fetuses are always male, and instead of gaining an XY pair of the chromosome, they acquire XXY or XXXY sex chromosomes.
The chromosomal abnormalities in babies can be detected with ultrasound markers. They are identified by a thick skin called nuchal fold behind the neck region, mild fluid collection between the brain's ventricles, absence of nasal bone, white spots in the abdomen and heart of the baby, short legs and arms, choroid plexus cysts in the brain, aberrant subclavian artery in the neck portion, etc. These chromosomal markers are sometimes present even in normal babies and ruling out any chromosomal issue is possible only with non-invasive prenatal testing (NIPT). After NIPT, as a next step, the physicians will recommend the expecting mothers to follow up with CVS or amniocentesis to confirm the results. By doing so, the issues that are not detected through NIPTs will also get ruled out.
How Is an Anomaly Scan Performed?
Once the expecting mother is ready to get herself scanned, a gel is applied to her abdomen. The examination is done with the help of a probe that resembles a small torch. When the probe is run through the abdomen, the inside of the womb appears on a TV screen. An anomaly scan examination usually lasts for about thirty minutes. It might take longer if the baby is in a tricky position in the womb or if the BMI of the expecting mother is high. If a problem is detected in an anomaly scan, the next procedure or course of action is recommended to the mother. When the problem is serious, the family is offered support and time to make a choice on what to do next.
As the fetal anomaly scan is important, expecting mothers should never miss it under any circumstance. Feel free to contact Anderson Diagnostics & Labs in Chennai, the best anomaly scan centre with the most experienced radiologists, to assess the clinical parameters and provide accurate results.