Amniocentesis Test During Pregnancy By Prerna Jhawar

8 min read

Reviewed by Dr Prerna Jhawar MBBS, MS(Obstetrics and Gynaecology),
FFM Consultant, Fetal Medicine,
Rainbow Children's Hospitals, Bengaluru

Dr Prerna Jhawar

Dr Prerna Jhawar is a Fetal medicine expert with 12+ years of experience. As a Fetal medicine expert, Dr Prerna takes care of babies while they are still in their Mother’s womb! Sharing the More

Written by Editorial Team

Editorial Team

Amniocentesis

Various tests and diagnoses are unavoidable in the course of pregnancy to gather relevant information, mainly if the pregnancy goes down under the ‘high-risk category. These tests reveal several significant issues that affect the normal course (and outcome) of pregnancy. And it also helps to find practical solutions and even terminate the pregnancy (if the result of that pregnancy is going to be an unfortunate event) after discussing it with the parents. The amniocentesis test is one such prenatal test.

This article provides necessary information about the amniocentesis test. Find how it is helpful. We also explain the whole procedure for your better understanding.

In This Article

Why Is Amniocentesis Test Recommended?

Amniocentesis (commonly called amnio) is a prenatal test that helps your doctor to collect details about your baby’s health by testing the amniotic fluid that surrounds the baby. Fetal cells, chemicals, and microorganisms in the amniotic fluid provide a lot of information regarding the growing baby inside you.

Amniocentesis is an essential prenatal diagnostic tool for finding out if the fetus has chromosomal abnormalities (including Down syndrome and genetic diseases such as sickle-cell anemia).

Which Disorders Can Be Detected Through Amniocentesis Test?

Which Disorders Can Be Detected Through Amniocentesis Test_

Amniocentesis helps to detect several hundreds of genetic disorders and nearly most chromosomal abnormalities. The severity, though, cannot be determined precisely by performing this examination. The test can also not detect any structural birth defects, like heart malformations or a cleft lip or palate.

Here is the list of 10 most commonly recognized disorders and defects by performing amniocentesis:

1. Down syndrome/ trisomy 21

Down syndrome, also known as Trisomy 21, is a condition in which additional hereditary material (extra full or partial copy, of chromosome 21) affects the mental and physical development of the baby

2. Turner syndrome

Turner syndrome is a chromosomal condition that affects only the baby girls (1 in every 2500 girls are found to born with this chromosomal disorder). Partially or entirely missing the X-chromosome is the reason behind this condition. Girls with Turner syndrome appear shorter than average height, and usually, will not attain puberty and will be not able to conceive (infertile), as the ovary will not be functioning

3. Patau syndrome/Trisomy 13

This is a rare genetic disorder in which the genetic materials of chromosome 13 (all or partially) appear three times. Severe physical and mental impairment is the outcome of this syndrome

4. Edward’s syndrome/Trisomy 18

This is the most common trisomy syndrome after Down’s syndrome. Here, the baby will have three copies of chromosome 18. Most of the babies are not able to survive the second and third trimester of pregnancy. They develop many issues related to organ systems and possess physical deformations

5. Cystic Fibrosis

cystic fibrosis

This is a genetic disorder, which can be fatal, and affects mostly the lungs and digestive system of the baby. It affects the exocrine glands, creating thicker mucus and saltier sweat

6. Tay-Sachs Disease

The defective gene of the 15th pair of chromosomes is the reason behind this disease. The baby may seem normal for around three to six months old. Their nervous system becomes progressively damaged, affecting their mental and physical abilities

7. Blood disorders like Sickle Cell Anemia, Thalassemia

sickle cell anemia

Sickle cell anemia is a genetic blood disorder.  Not having enough healthy RBC to carry oxygen is one of its striking characteristics. Normally the blood cells are round and flexible. Whereas in babies with sickle cell anemia, the blood cells will be irregular in shape, rigid and sticky.

8. Muscular dystrophy

Muscular dystrophy is a condition in which the muscle of the body gets progressively weaker and eventually stops working. This condition comes about due to the mutation in X-chromosome.

9. Rare Genetic disorders

Many genetic disorders run in families and if the exact genetic mutation for the index cases is available, we can test the same defect in unborn babies by amniocentesis.

10. Fetal Infections

Mothers may sometimes be affected by certain viral infections like rubella and many others which may affect the fetus. This may sometimes be evident on scans in the form of certain findings like ventriculomegaly etc., and sometimes may not be evident. The confirmation of fetal infection can be done by amniocentesis.

Who Is Recommended For Taking The Amniocentesis Test_

Doctors recommend amniocentesis when the pregnancy has an expanded danger of hereditary issues and chromosomal issues. In normal pregnancies, this test will not be conducted as the procedure of amniocentesis carries the risk of a miscarriage.

Specialists offer Amniocentesis if,

  • The mother delivered a baby with Down syndrome or other chromosomal or hereditary issues in her previous delivery.
  • Genetic birth defects run in the family.
  • The screening test during the first trimester determines a genetic disorder or shows abnormal readings.

The screening Tests Include

  • Noninvasive prenatal screening tests (NIPT) after the 10th week of pregnancy
  • Nuchal Translucency Scan
  • The dual test which measures human chorionic gonadotropin (hCG) and Pregnancy-Associated Plasma Protein ( PAPP-A), is a triple screen that measures three substances [alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol] or quad screen, which measures four substances [estriol, inhibin A, human chorionic gonadotropin (hCG), and alpha-fetoprotein (AFP)] in the mother’s blood, to find if the baby possesses any chance to develop birth defects like Down syndrome.

When Is The Amniocentesis Test Conducted?

The doctor usually schedules the procedure of amniocentesis between the 15th and 18th week of pregnancy. As late as around the 24th week, sometimes, the doctor may suggest an amniocentesis test.

In the case of membrane rupture, Amniocentesis at any time during the last trimester may be needed. This is to evaluate uterine infections due to the premature rupture of the membrane. It also determines the severity of fetal anemia. The results help to decide whether a blood transfusion is necessary to save the life of the baby. It also helps to determine the maturity of the fetal lung.

What Is The Procedure Of the Amniocentesis Test?

amniocentesis test

The entire process will take about 30 minutes. For the process of amniocentesis, you must lie down on your back. The doctor or nurse wipe the abdomen with an iodine solution to prevent any infection. The position of the amniotic sac, placenta, and fetus is located by performing an ultrasound simultaneously with the procedure.

By the utilization of ultrasound side by side, doctors can lower the slight danger of unintentionally pricking the embryo during this procedure. You may get an injection to numb the abdominal area. Most doctors may not administer this injection though, as there is no significant difference between the pain of injection and the pain of the insertion of the needle.

The doctor will then draw out a sample of the amniotic fluid which will contain fetal cells. These fetal cells will be sent to the laboratory for testing for genetic conditions.

Risks Of Conducting Amniocentesis Test

Risks Of Conducting Amniocentesis Test

An experienced registered diagnostic medical sonographer conducts amniocentesis. It also has continuous ultrasound guidance throughout the procedure. Even then, as it is an obtrusive analytic test, amniocentesis does have a few risks.

Miscarriage

Miscarriage is the most common risk that is related to amniocentesis. The risk of miscarriage due to amniocentesis performed during the second trimester is very low. Whereas, in amniocentesis before the 15th week of pregnancy, the chance of pregnancy loss increases. However, the overall possibility is very low as it ranges from 1 in 500 to 1 in 200.

Injury

The odds of the baby having a minor needle injury are quite low. However, the baby might get a needle injury if its arms or legs suddenly come into the needle’s way. The chances of serious injuries are rare.

Spotting and Fluid Leakage

Though on rare occasions, amniotic fluid leaks (through the vagina) after amniocentesis. The amount of fluid loss is very low and will cease within a week without affecting the normal progress of the pregnancy. The spotting will also stop eventually, after proper rest.

Infection and Cramps

Though not often, amniocentesis can set off a uterine infection in some cases. Likewise, many women experience cramps similar to slight menstrual cramps and discomfort for some time after the procedure of amniocentesis.

You should contact your doctor and seek medical attention immediately if you experience fever, increased vaginal discharge (more than minor spotting), or abdominal pain, which is more severe than slight cramps.

What Happens If It Is Found That My Baby Has A Problem?

What Happens If It Is Found That My Baby Has A Problem_

In such a scenario, genetic counseling provides you with more information regarding the problem and discusses the options. You may decide to continue or terminate the pregnancy. Many support groups exist in both online and offline spaces, and some women may find them helpful. Whatever you choose, you can opt for further counseling and seek support.

Amniocentesis tests during pregnancy may be essential to determine the presence or absence of genetic conditions in the fetus so that parents and doctors can determine further course of action. Due to the risks that this test may carry, your doctor will prescribe it only when they deem it absolutely necessary.

FAQ’s

1. How Painful Is An Amniocentesis?

You may feel some discomfort during an amniocentesis, but it is normally not severe. There have been reports of pressure or discomfort comparable to that of a woman’s menstruation after the needle has been removed.

2. Is Amniocentesis Safe For The Baby?

The majority of amniocentesis procedures are risk-free. If you get amniocentesis after 15 weeks of pregnancy, your chances of miscarriage will be one in a hundred. Yet, the danger increases if the surgery is performed before 15 weeks. It is unknown why amniocentesis might result in a miscarriage.

3. Do I Need Bed Rest After Amniocentesis?

Amniocentesis does not need bed rest, however, it is important to avoid strenuous activity like exercise or carrying heavy objects for at least 24 to 48 hours. Most miscarriages after amniocentesis occur during the first three days after the surgery. Yet, there are occasions when it happens as much as two weeks later.

4. How Long Do Amniocentesis Results Take?

Within three business days, you should have the first results of the test, which will tell you if your baby has a health problem or chromosomal problem. If tests are also done for less common conditions, the results can take up to three weeks or longer to come back.

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Editorial Team,

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.Read more.

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