This procedure involves removing some of the amniotic fluid from the sac surrounding the fetus for testing and treatment. After taking all sterile precautions, a fine needle is inserted into the uterus through the abdomen with ultrasound guidance. After the amniotic fluid is obtained, it can be sent for genetic tests/chromosomal abnormalities based on the indication.
Why it’s done
Amniocentesis can be done for various reasons:
- Genetic testing. Genetic amniocentesis involves taking a sample of amniotic fluid and testing it for certain conditions, such as Down syndrome.
- Fetal lung testing. Fetal lung maturity testing involves taking a sample of amniotic fluid and testing it to determine whether a baby’s lungs are mature enough for birth.
- Diagnosis of fetal infection. Occasionally, amniocentesis is used to evaluate a baby for infection or other illness. The procedure can also be done to evaluate the severity of anemia in babies who have Rh sensitization — an uncommon condition in which a mother’s immune system produces antibodies against a specific protein on the surface of the baby’s blood cells.
- Treatment. If you accumulate too much amniotic fluid during pregnancy (polyhydramnios), amniocentesis might be done to drain excess amniotic fluid from your uterus.
- Paternity testing. Amniocentesis can collect DNA from the fetus that can then be compared to DNA from the potential father.
Genetic amniocentesis can provide information about your baby’s genetic makeup. Generally, genetic amniocentesis is offered when the test results might have a significant impact on the management of the pregnancy or your desire to continue the pregnancy.
Genetic amniocentesis is usually done between weeks 15 and 20 of pregnancy. Amniocentesis done before week 15 of pregnancy has been associated with a higher rate of complications.
You might consider genetic amniocentesis if:
- You had positive results from a prenatal screening test. If the results of a screening test — such as the first trimester screen or prenatal cell-free DNA screening — are positive or worrisome, you might opt for amniocentesis to confirm or rule out a diagnosis.
- You had a chromosomal condition or a neural tube defect in a previous pregnancy. If a previous pregnancy was affected by conditions such as Down syndrome or a neural tube defect — a serious condition affecting a baby’s brain or spinal cord — your health care provider might suggest amniocentesis to confirm or rule out these disorders.
- You’re 35 or older. Babies born to women 35 and older have a higher risk of chromosomal conditions, such as Down syndrome. Your health care provider might suggest amniocentesis to rule out these conditions.
- You have a family history of a specific genetic condition, or you or your partner is a known carrier of a genetic condition. In addition to identifying Down syndrome and the neural tube defect spina bifida, amniocentesis can be used to diagnose many other genetic conditions — such as cystic fibrosis.
- You have abnormal ultrasound findings. Your health care provider might recommend amniocentesis to diagnose or rule out genetic conditions associated with abnormal ultrasound findings.
About Dr. Rajeshwari Pawar
Dr. Rajeshwari Pawar comes with over 23 years of experience working with the most reputable national and international institutes. She is a renowned clinician who ensures a memorable pregnancy and delivery experience for her patients and their families.