Detailed Anomaly Scan

Detailed Anomaly Scan

Most women are offered a detailed ultrasound scan at 18-24 weeks to see if your baby is developing normally. 

Why have a Detailed anomaly scan?

The vast majority of babies are normal. However all women, whatever their age, have a small chance of delivering a baby with a physical or a mental problem. Many such abnormalities can be diagnosed and ruled out with the Detailed Anomaly Scan. Reasons to have this scan include:

• To reassure you that your baby is likely to be normal
• To confirm the gestational age of your pregnancy
• To confirm the number of fetuses and, if twins, whether they are identical or not
• To detect birth defects, such as a spina bifida or heart problems
• If you are concerned about the chances of chromosome problems like Down syndrome, this scan can search for subtle markers that may suggest a higher risk that your baby may have one of these problems
• If you want to know your baby's gender this can usually be seen at this scan

When you attend for this scan we will tell you about everything that we see, unless you advise us that there are certain things that you don't want to know about, such as your baby's gender or markers for chromosome problems. 

What can this scan detect?

This ultrasound scan is very accurate but unfortunately it cannot diagnose 100% of congenital abnormalities. If the scan is complete, we would expect to pick up at least 95% of cases of spina bifida, 80% of cases of cleft lip or palate, and 60% to 70% of cases of congenital heart disease. 

This scan can also identify 50% to 70% of cases of Down syndrome, but the First Trimester Screening (FTS) test is better for this. Because 30% to 50% of cases of Down syndrome appear normal on ultrasound, only an amniocentesis can give you this information for certain. It is also important to realise that ultrasound scans in pregnancy do not detect problems like cerebral palsy or autism. 

Sometimes babies with chromosomal abnormalities have signs called ultrasound markers. These include thick skin in the neck, excess fluid in the kidneys, short arms or legs, white spots in the baby's heart or abdomen, or choroid plexus cysts in the brain. While some babies with chromosomal abnormalities have these markers, it is important to remember that many normal babies also have these signs. 

The only way to diagnose or exclude a chromosomal problem for certain is to have an amniocentesis. If you would prefer not to know about these markers please inform us prior to the scan. If the scan suggests a problem, you will be told this immediately. You will be able to discuss the findings immediately with a consultant who specializes in fetal medicine. 

A full support service will be available for you should any problems be detected, including a referral to an appropriate pediatrician. A copy of your report will be sent to your referring hospital, doctor or midwife to ensure good communication.

Is the Baby Girl or Boy????

For centuries, expectant parents had to wait until the moment of birth to learn the sex of their babies. Of course there have always been old wives' tales and superstitions about figuring out baby gender. Below are a few examples of old wives' tales that I know;

1. Ancient Chinese Pregnancy Calendar

2. Wedding Ring Gender Prediction

Take off your wedding ring and put a thread thru the wedding ring. Dangle the wedding ring over the mom's pregnant belly while lying down. If the wedding ring swings in a circle motion then it's a GIRL! If it moves back and forth like a pendulum then it's a BOY!

3. Your Eyeballs Knows!

Look in the mirror and pull down the skin under your LEFT eye. Look at the white part of your eyeball. Do you see a vein that looks like a 'V' or branches? If so then it's a GIRL!

4. The way you carrying your baby

Look at yourself in the mirror, full length - wow you are beautiful (^_^). Now turn to the side and see whether your tummy is high or lowered? If it's high then congratulation! It COULD BE a GIRL! If your tummy is lowered then congratulation! It COULD BE a BOY!

Did any of the above old wives' tales prove your baby's sex correctly?

In modern days, you don't need to be puzzled and wait till your baby delivered to prove all these old wives' tales. Thanks to the wonders of modern technology, moms and dads these days are able to find out their baby's gender with ultrasound months before delivery. Ultrasound don't just reveal the baby's gender; the procedure is done mainly to take an early look at the fetus to make sure it's developing properly. 

The male and female sex organs can appear similar at 4th to 6th weeks and start to differentiate at 10th weeks for male and 20 weeks for females. The majority of couples find out their baby's gender during 2nd trimester ultrasound (18th-26th weeks of pregnancy). For some newer and advanced ultrasound technology, the baby's gender can be determined as early as 12th or 13th weeks!

Having ultrasound to find out your baby's gender is a fairly straightforward and safe procedure, and many expectant parents want to know this before the baby is born. That way, they can settle on a name for the baby, start decorating the nursery and buy for clothing for either a girl or a boy. Baby shower gift choices are also simpler this way. Some people feel this might also strengthen the bond with the baby, who now has a specific identity.

What does a baby BOY look like on an ultrasound scan?

Baby Boy on 2D scan

Baby Girl on 2D scan

Baby Boy (Left) and Baby Girl (Right)
on 3D/4D

Nuchal Translucency Screening

What is Nuchal Translucency?

 Nuchal translucency (NT) is the sonographic appearance of a collection of fluid under the skin behind the fetal neck in the first-trimester of pregnancy.

Who Nuchal Translucency screening is for?

NT screening is available for any pregnant woman. However it can be especially helpful for;

->  Older moms-to-be (>40 years old)

-> Family history of Chromosomal abnormalities

-> Mother who may be hesitant about more invasive genetic testing, like CVS and amniocentesis, because of the increased risk of miscarriage associated with them.

How accurate this Nuchal Translucency screening is?

The accuracy of the test is, however, dependent on the;

->  Skill of the sonographer performing it

-> The sensitivity of the equipment

NT measurements are not conclusive, so the NT screening test can't tell you for sure whether your child has a chromosomal disorder, but it can be combined with other data as below to provide a statistic about the likelihood of such a disorder;

-> Older pregnant woman (>40 years old)

-> Family history of Chromosomal abnormalities

-> Blood tests - beta-hCG and pregnancy associated plasma protein A (PAPPA-A)

The results of these two blood tests plus the NT screening, known as the first trimester combined screening, can be combined into one number that represents the likelihood of having a child with a genetic abnormality. This information can be helpful to parents who are trying to decide whether to have more invasive genetic tests, such as amniocentesis or chorionic villus sampling (CVS).

How Nuchal Translucency screening is done?

This procedure is done during an ultrasound. The sonographer will first move the transducer across your belly to measure your baby from crown to rump to ensure that the fetal age is accurate. The fetal crown-rump length should be between 45 and 84mm. Then he or she will locate and measure the nuchal translucency (if you're lucky your baby will cooperate by moving into a position where the measurement will be optimum).

When Nuchal Translucency screening is done?

NT screening must be done between weeks 11 and 14. That is why an accurate date of conception is important for an accurate result. Before 11 weeks, the scan is difficult to be done because your baby is still so tiny. It would also be too early to combine it with your first trimester blood test. After 14 weeks, any excess fluid may be absorbed by your baby's developing lymphatic system. 

What is the normal measurement?

An NT of less than 3 mm is considered normal when your baby measures between 45mm and 84mm. The NT normally grows in proportion with your baby.

What abnormal result mean?

An increased NT (>3 mm) means there is a greater risk of chromosomal abnormalities or cardiac defect. However, it does not tell for certain that the baby has chromosomal abnormalities.

What should I do if I’m high risk?

The only way for certain if your baby has Down’s syndrome or other chromosomal abnormality is to have a diagnostic test such as CVS or amniocentesis.

Which One is the Actual Dates for My Baby's Delivery?

Have you ever encountered any of these situations?

©  Your baby gestational age measured by ultrasound not correlates with gestational age calculated by your last menstrual period?

©  Your expected dates of delivery vary every time you do the ultrasound scan?   

Owh no!! How I’m going to plan my delivery if the dates vary????!!

Calm down and take a deep breath. Read this carefully before you start panicking others…

Usually it is still considered to be normal measurement or correlates to the actual dates/age if the difference;

©  3-5 days if ultrasound scan is performed during 1^st trimester

©  14 days if ultrasound scan is performed during 2^nd trimester

©  21 days if ultrasound scan is performed during 3^rd trimester

Ultrasounds are not completely accurate at estimating the due date of the pregnancy. There are several reasons why this difference happens;

©  Fetuses can bend and stretch so the measurements will not be exactly the same

©  There is always normal biological variation between different fetuses

©  The accuracy of the measurements also depends on the skill of the sonographer and the quality of the equipment

If yours still within the range so no need to worry so much. As long as the other important parameters are also within normal range, your baby will grow up well.

What Can We See in Dating Scan?

Since dating scan is done at early first trimester, we usually can see;

©  The baby with heart beat

©  Gestational sac (it is a sac containing the baby)

©  Yolk sac (baby’s food resource, it usually disappear after the placenta take over the role)

©  The limb buds (these will develop into upper limbs and lower limbs)

Usually the sonographer will measure the Crown-Rump Length (It’s a length of baby from head to buttock) and the size of the Gestational Sac. From those measurements the ultrasound machine will calculate your baby’s current age and your baby’s expected date of delivery.

Dating Scan

What is Dating Scan? It is the first ultrasound scan for your pregnancy. Most mother doesn’t know when they should have their first scan. Dating scan is done during your early pregnancy, usually between 8-11 weeks of gestation. Dating scan is important in;

1. Confirming the correct dates of your pregnancy

• The earlier the ultrasound scan is done, the more accurate it is at estimating the baby's due date. This is because the fetus is growing so quickly that there is a big difference in size from week to week. Below is table showing the accuracy for each trimester;

Trimester	Accuracy of estimated date of delivery (EDD)
First	3-5 days
Second	14 days
Third	21 days

2. Confirming the presence of baby's heart beats

3. Confirming the location of your pregnancy

• This is important to make sure that the baby is inside the uterus.
• There is a condition where baby is not inside the uterus is what we called as ectopic pregnancy. This kind of pregnancy is dangerous as it can cause severe blood loss to the mother if it is ruptures.

4. Determining the number of your babies (singleton/twin/triplet)

5. Identifying pregnancies at increased risk of miscarriage or pregnancy loss e.g molar pregnancy

6. Identifying other abnormalities within your pelvic area such as uterine anomalies, fibroid and ovarian cyst.