What is Amniocentesis?
Amniocentesis is a prenatal test that has very high accuracy. Genetic conditions and abnormalities in the fetus can be brought to light by taking a sample of the amniotic fluid from the uterus and running it under this test.
Who should have Amniocentesis?
- Women who get positive results from noninvasive prenatal blood tests and other such prenatal screening tests
- Babies born to women of older age have a higher risk of developing down syndrome and other such genetic conditions, hence women who conceive after the age of 35 years and above must undergo amniocentesis
- Have a history of sickle cell disease, cystic fibrosis, Down syndrome and other genetic conditions in their family
- Have experienced chromosomal conditions like neural tube defects (a condition that affects the spinal cord and brain) during previous pregnancies
Importance of Amniocentesis
- To detect intrauterine infections
- To determine the gender of the baby
- For the detection of hereditary conditions like Down syndrome, spina bifida, etc.
- To decrease the amount of amniotic fluid in the uterus in cases of Polyhydramnios
- To examine the development of the lungs in babies, in case there is a need for early delivery due to complications
- In case of blood sensitization of the mother, the test helps to monitor the health of the baby
- To examine the baby for the presence of any life-threatening condition
When to perform Amniocentesis?
During the 15th and 20th week of pregnancy i.e. the second trimester. However, in certain cases, the procedure is done during the third trimester, in the later stages of pregnancy, particularly before a c-section or preterm delivery.
How to prepare for Amniocentesis?
- Avoid lovanox and heparin at least 24 hours before the procedure
- A full bladder helps to get better results, hence women may be asked to drink lots of water before the ultrasound
- Avoiding the use of Aspirin pills at least five days before the amniocentesis procedure
Procedure for Amniocentesis
- Important to perform an ultrasound at the beginning of the procedure to know the exact position of the fetus, amniotic fluid pockets, and placenta
- An antibacterial solution is used to disinfect the mother’s belly area to ensure that the collection of the sample does not lead to an infection of the amniotic fluid
- While monitoring the path on the ultrasound, the diagnostician uses a thin needle to collect a sample of the amniotic fluid
- After collection of the fluid sample, the ultrasound is used to ensure that the fetal heartbeat is normal and stable
- The sample is sent for karyotyping, examining the chromosomes
Pain associated with Amniocentesis
Feeling a sharp pinch along with immense pressure when the needle goes through the uterus. The pain is quite intense, however, it does not last for more than a few seconds and there is no pain when the needle goes through the abdomen. Apart from this, patients do not usually complain of any other severe pain during the procedure for amniocentesis.
Need for aftercare in case of Amniocentesis
- Women must drink fluids in sufficient quantities to make up for the loss of the amniotic fluid collected as a sample
- After the test, the doctor advises 24 hours of complete bed rest
- Stress and anxiety related to the test may be harmful to the baby, hence, mothers must practice relaxation techniques
- Follow a healthy diet consisting of dairy products, fresh vegetables, and fruits
How long does it take to get the results for Amniocentesis?
Time taken to obtain the results, depends on the purpose of the test:
- Checking for neural tube defects, protein levels in the fluid and fetal abnormalities – within 10 days
- Checking for the genetic condition in the baby – up to 2 weeks
- Fluorescent in situ hybridization (FISH) test along with amino to check for chromosomal abnormalities in the baby – within a few days
Side effects of Amniocentesis on the mother
The chances of women experiencing side effects due to amniocentesis are very less because there is a detailed screening procedure that is undertaken before the test is done. However, the following are side effects that the mother may experience:
- Leakage of amniotic fluid results in continuous vaginal wetness
- After the collection of the fluid sample, a woman may experience mild to moderate cramping that continues for a few hours
- In rare cases, the woman may have severe to moderate headaches
- Irritation and soreness at the spot where the doctor inserts the needle last for a few days
Risks for the baby in case of Amniocentesis
- Rh sensitization: The blood cells of the baby may enter the bloodstream of the mother in some rare cases. If the mother has Rh-negative blood, it may cause complications as the mother’s body may produce antibodies against the baby’s blood cells. To avoid such a condition, the doctor administers Rh immunoglobin to the mother after the test.
- Amniotic fluid leakage: Leakage may occur soon after the test, but it stops on its own. However, severe leakage may cause orthopedic complications for the baby.
- Scarring: Performing the test during mid-trimester may cause scarring or depression on the baby’s body.
- Uterine infections may occur in some rare cases
- Infection transmission: Diseases like HIV, Hepatitis C or toxoplasmosis that affect the mother may transfer to the baby while conducting the test
- Needle injury: Serious injuries are rare, but they may injure the leg or the arm if it comes in the way of the needle
Limitations of Amniocentesis
- The amnio test may be difficult to interpret, however, the results are very accurate and they may require additional chromosomal testing
- Genetic and chromosomal disorders in the baby are traceable through amniocentesis but it does not detect autism, heart defects, nonspecific mental retardation, etc. Thus, negative results in the test do not guarantee a normal baby
Alternatives to Amniocentesis
Instead of the amnio, people can use certain non-invasive DNA fetal tests. In such a test, the doctor collects the blood samples from the mother to map the DNA of the fetus. It reduces the risk of miscarriage.
Danger of Miscarriage
The risk of miscarriage ranges from 1 in 300 to 1 in 500 due to amniocentesis. The danger is higher in cases where one conducts the test before the 15th week of pregnancy. Risk of miscarriage is also higher in women carrying triplets or twins.
Cost of Amniocentesis
The cost of Amniocentesis may differ in various countries. However, commonly the price ranges between $1000 – $1500.