Amniocentesis: What to Expect

One Amniocentesis The test is a prenatal test that can diagnose certain health conditions in the unborn baby.

Your healthcare provider may give you this test while you are pregnant. Usually, this is because your baby is at risk for a genetic disorder or a neural tube defect. Amniocentesis carries some risks, and while many parents-to-be do it, others decide against it.

This article will introduce you to the procedure and purpose of amniocentesis, what to expect before, during, and after the test, and what the results mean for you and your baby.

What is amniocentesis?

To perform an amniocentesis, a healthcare provider will take a small sample of amniotic fluid for testing. The fluid contains cells and substances that can provide clues to the baby’s health.

The results are quite accurate. If prenatal screening shows that your child may have certain genetic disorders or birth defects, your healthcare provider or obstetrician may recommend amniocentesis.

Amniocentesis can also tell your baby’s gender, identify prenatal infections, and assess lung development.

Genetic testing: why and how

What is amniotic fluid?

Amniotic fluid is the fluid around your baby. It is located within a membrane called the amniotic sac.

When your “water breaks,” it’s the sac that ruptures and releases the amniotic fluid. The liquid is clear and slightly yellow. It has a variety of uses, including:

  • It keeps the temperature constant.
  • It provides cushioning for your baby.
  • It flows into and out of your baby’s mouth and lungs and helps with lung development.
  • It allows the baby to move, which helps with bone growth.

Purpose of amniocentesis testing

Amniocentesis can diagnose many health problems. These include:

  • Inherited diseases: diseases caused by genetic mutations, such as cystic fibrosis, Tay-Sachs disease, and Fragile X syndrome
  • Chromosomal disorders: disorders caused by abnormal, missing, or extra chromosomes (genetic material), such as Down syndrome, learning disabilities, or other health problems
  • Neural tube defects: abnormal development of the baby’s spine and/or brain

Amniocentesis can also tell your baby’s gender, identify prenatal infections, and assess lung development. There are several reasons why some parents want to know this information before birth:

  • Emotionally and logistically preparing infants with special needs
  • Alleviating fears of possible genetic diseases
  • Get a realistic view of the development of babies at risk of preterm birth
  • Decide whether to terminate the pregnancy

Questions to ask your healthcare provider

  • How likely are you to pass a genetic disease to your baby?
  • What is the risk of a baby with birth defects?
  • What should I do if the result is positive?
  • What is the risk of false positives?
  • What are the risks of amniocentesis?
  • How should you prepare for the exam?
  • When will the results come back?

Who is a good candidate?

If your healthcare provider thinks you’re a good fit for an amniocentesis, they may recommend that they have an amniocentesis. Their criteria may include:

  • Other tests that indicate a high risk of birth defects
  • Your family or partner’s history of birth defects
  • Both parents carry the abnormal gene associated with the disease
  • Your baby is at risk for STDs
  • you are over 35 years old

For these reasons, amniocentesis is usually performed in the second trimester. Use in the third trimester may be recommended if:

  • Your baby is at risk of being born prematurely (check lung development)
  • Uterine infection
  • Rh disease

What is Rh disease?

When your blood is negative for Rh factor (A-, B-, O-, or AB-) and your baby is positive, it is possible to have Rh disease. Your immune system may recognize the baby’s blood as a threat and try to destroy it.

RhoGAM injection for Rh disease prevention

what to expect

Second-trimester amniocentesis is usually performed between the 15th and 20th week of your pregnancy. The test itself only takes about 15 minutes.

before testing

You will be told if your bladder is full or empty. The later the test is done during pregnancy, the more likely it is that you will need to empty your bladder.

Consult your healthcare provider or testing agency if you need to do any other preparations. Check your insurance to see if the test is covered and how much you will pay.

On test day, wear clothes that are easy to take off. Leave jewelry and other valuables at home. Make sure you have an insurance card and copay if required. Arrive as early as possible so that the test will be done before the scheduled time for the amniocentesis.

During the test

For the test, you will lie on your back. A healthcare provider will use an ultrasound to see where the baby is and determine a good insertion point.

They may put numbing medication on the insertion point. They will then use a small needle to draw out some of the fluid. After getting the sample, they will go on to perform an ultrasound to monitor the baby’s heartbeat.

You may have some mild discomfort or cramping during or after the procedure. This is normal. If you have any concerns, please let your healthcare provider know at any time.

after test

After that, you will stay in the office or testing facility for about an hour. So they can monitor you and the baby. Tell others if you feel dizzy or nauseous.

Once you are released, it is best to go home and rest. Do not do any strenuous exercise for about 24 hours after that. If you have lingering discomfort, ask your healthcare provider if any medicines are okay to take. Other reasons to contact your healthcare provider include:

  • Bleeding from the vagina or needle insertion site or leaking amniotic fluid
  • severe abdominal pain or cramping
  • fever or chills
  • Changes in your baby’s activity level

What do the test results mean?

Ask your healthcare provider when you should expect results from amniocentesis. This may take days or weeks.

A positive result means the test found a genetic abnormality or other problem. You may be contacted by your healthcare provider, genetic counselor, or obstetric genetics specialist.

They will review the results with you so you can see what they mean. You may need to make decisions about treatment or other actions based on the results.

How accurate is amniocentesis?

Amniocentesis is very accurate. In fact, it’s close to 100%.

It can detect many health conditions, but not all. Therefore, a negative amniocentesis does not guarantee that your baby will be born healthy. It only looks for very specific conditions and problems.

What can’t amniocentesis detect?

Amniocentesis cannot detect all birth defects and health problems.

For example, it will not find structural problems such as heart problems, cleft lip or cleft palate. However, ultrasound can detect many structural defects.

Some preliminary research suggests that amniocentesis may be able to detect autism spectrum disorder (ASD) based on testosterone levels. Further research, however, has had mixed results. Therefore, currently, this test is not used to diagnose ASD.

Risks of amniocentesis

Amniocentesis has some risks. These include:

  • cramp
  • Bleeding / leaking of amniotic fluid from the vagina or puncture site
  • Infect
  • premature birth
  • abortion

The risk of miscarriage after amniocentesis in the second trimester is less than 1%. This is a slightly increased risk than normal.

The risk is higher before the 18th week of pregnancy. Many health care providers will not perform this test until then.

Depending on your health or other factors, you may be at additional risk.

Signs of miscarriage after amniocentesis

  • vaginal spots
  • abdominal pain or cramping
  • fluid or tissue from the vagina

Feel free to contact your healthcare provider if you experience vaginal bleeding during pregnancy.


Amniocentesis is a highly accurate test. It involves drawing amniotic fluid and testing it for genetic conditions and other problems. It is also used to determine gender and lung development.

A positive result means the test found something. Your healthcare provider can explain what this means.

This test slightly increases your risk of certain complications, such as miscarriage and premature birth. Report any signs to your healthcare provider immediately.


  • put you at ease

  • Set aside time to prepare for children with special needs

  • More accurate than screening tests


  • time consuming

  • Can be expensive (depending on your insurance)

  • Minor risk of miscarriage or preterm birth

VigorTip words

If your healthcare provider recommends an amniocentesis, you need to decide whether or not to have it. up to you.

You can decide that the minimum risk is worth it for peace of mind or to give you time to prepare. On the other hand, you might decide that the test isn’t worth it because it won’t change your pregnancy or your preparations.

Rest assured, many parents have made the same decision as you. This is a very personal choice you should make with your family and medical team.

Frequently Asked Questions

  • How painful is amniocentesis?

    Usually not painful. You may feel uncomfortable during the test. After that, you may experience cramps similar to your period. If you are concerned about injury to the amniocentesis needle, ask if your abdomen will be numb before inserting the needle.

  • How much does amniocentesis cost?

    Amniocentesis can cost anywhere from a few hundred dollars to several thousand dollars. It depends on where you did it. Insurance usually pays for all or most of the cost of the test. Be sure to check before the exam so you won’t be surprised when the bill comes.

  • Can I choose not to have an amniocentesis?

    Yes, choosing not to have amniocentesis is a valid option. This is a very personal decision and should be made by you and your partner or family member and your healthcare provider.