Amniocentesis helps in early detection of fetal defects

After diagnosing a fetus with a chromosomal abnormality, your doctor will order some more intensive tests such as amniocentesis or placenta biopsy to arrive at a final conclusion. 

What is amniocentesis and placenta biopsy? What are these methods of help for pregnant mothers and what should be kept in mind when doing? Let's learn with aFamilyToday Health through this article!

What are the procedures and amniocentesis?

Amniocentesis and placenta biopsy are tests that can tell you if your baby has chromosomal problems or certain genetic disorders.

1. Placenta biopsy (CVS)

Placenta biopsy (CVS) is done early in pregnancy (usually between 10 and 13 weeks) so you can find out about your baby's condition early. If there is no problem, the pregnant mother will soon relieve the burden of worry. Unfortunately, if a serious problem occurs, you can choose to abort early in your first trimester.

The placenta biopsy causes bleeding that leads to the mixing of your blood and that of your baby. If your Rh is negative, you will be given an injection of a serum Rh immunoglobulin (such as RhoGAM) to prevent harm to the fetus if the baby's blood is Rh positive.

Placenta biopsy is generally thought to have a higher rate of miscarriage than amniocentesis, but this may not be the case in all settings.

2. Amniocentesis

What is amniocentesis?

For pregnant mothers who want to wait for test results in the second trimester, before deciding to have an invasive test, amniocentesis is the only option. This procedure is usually done between 16 and 20 weeks of pregnancy  .

Amniocentesis is a prenatal test that allows the doctor to collect information about the baby's health from a sample of maternal amniotic fluid . The purpose of the procedure is to determine if the fetus has certain genetic disorders or chromosomal abnormalities such as Down syndrome .

Like the placenta biopsy (CVS), amniocentesis results in a karyotype. Through an image of the fetus's chromosomes, the doctor can be sure that the problem is occurring.

This procedure can be performed by anyone, especially those at high risk of genetic and chromosomal problems. Some other reasons for pregnant mothers to perform amniocentesis are:

Diagnose or rule out uterine infection to assess fetal status if the mother has a blood type problem such as Rh blood type heterogeneity. This is a complicated condition that occurs if the mother's blood type is different from the fetus

To evaluate the lung development in the fetus to see if it is eligible for the mother to give birth early for some health reason or not.

How is amniocentesis performed?

The amniocentesis usually takes about 20 to 30 minutes. Before the procedure, the doctor will do an ultrasound to measure the size and check the basic anatomy of the fetus, as well as determine the amniotic fluid bag to assess the safe distance of the baby and the placenta. Pregnant mothers lie on the examination table and their abdomen will be disinfected with an alcohol-iodine solution to reduce the risk of infection.

Then, the doctor inserts a long, thin, empty needle through the abdominal wall into the amniotic sac around the fetus to drain a quantity of amniotic fluid about 15 to 20 ml (about three teaspoons). This process takes about 30 seconds. The fetus will continue to make amniotic fluid to replace the water withdrawn.

You will feel a sharp, stinging pain during the procedure, or no discomfort at all. The degree of discomfort or pain in each woman and even at different pregnancies will vary.

Anesthesia can be offered, but the pain from an anesthetic injection can be worse than with an amniocentesis so most mothers decide not to anesthesia. Next, the doctor checks the baby's heart rate through the images on the ultrasound screen.

Today, doctors have more and more experience with advanced medicine, so amniocentesis does not pose much risk. Therefore, pregnant mothers should not worry when having to perform amniocentesis!

Disorders and defects that amniocentesis can detect

Amniocentesis can find almost all chromosomal disorders including Down syndrome, trisomy 13, trisomy 18 and sex chromosomal abnormalities (such as Turner syndrome ). This test can diagnose disorders but cannot gauge their severity.

There are hundreds of genetic disorders such as cystic fibrosis, sickle cell disease, and Tay-Sachs disease. This test cannot detect all disorders but if the fetus is at high risk, amniocentesis usually tells you if your baby is sick.

Neural tube defects such as splitting vertebrae and non-brain defects are done by measuring the concentration of a substance called alpha-fetoprotein (AFP) in the amniotic fluid. However, amniocentesis cannot detect other birth defects such as heart defects or chapped lips or cleft palate. Thus, many structural defects will be detected during ultrasound in the 2nd trimester.

Factors that put the fetus at risk for teratogenic disorders

1. Down syndrome

A pregnant woman has a screening test showing a baby at high risk of Down syndrome or another chromosomal problem.

2. Ultrasound results

Ultrasound results show that the fetus has structural defects related to chromosomal problems.

3. Screening results

This result shows that you or your partner has the abnormal gene. You and your partner are carriers of recessive genetic disorders such as cystic fibrosis or sickle cell disease.

4. Personal medical history

If you've ever had a baby with a certain genetic abnormality, there's a higher risk of a miscarriage with the next pregnancy.

5. Family history

If you or your partner has a chromosomal abnormality, an inherited disorder, or has a family with an inherited condition, your baby is also at higher risk for genetic problems.

6. Childbirth age

Any pregnant mother is capable of pregnant with a baby with chromosomal abnormalities. This risk increases with the age of the mother. For example, the chance of a fetus having Down syndrome increases from about 1 / 1,200 in a pregnant woman aged 25 to 1/100 in a pregnant woman aged 40.

Either way, the results of the amniotic fluid test are important in keeping the fetus. Hopefully, with the information that the article provides, it will help pregnant mothers have a healthy pregnancy!