Baby check: Amniocentesis
George and Rita are so excited, after years of waiting, finally they’re going to have a baby. Their excitement cannot be controlled as they excitedly pick out suitable baby names, buy baby clothes and baby things. They’re just so excited to meet the fruit of their love. However, all excitement turns into anxiety as their doctor advises them an amniocentesis.
“Amniocentesis? What is that all about? Is there something wrong with our baby?” Questions flood their mind as they think about their child and imagine possible worst case scenarios happening.
“No, this can’t be. Please let there be nothing wrong. Please let all be well” They say to their own selves as they contemplate on what their doctor said and pray for a miracle.
Amniocentesis: Should I be worried?
Amniocentesis is defined as a procedure in which amniotic fluid, the fluid that surrounds and protects the baby during pregnancy, is removed from the uterus for testing or treatment. This fluid contains fetal cells and various chemicals produced by the baby. It is used in the prenatal diagnosis of chromosomal abnormalities and fetal infections during pregnancy. In other words, it is done to look for birth defects and genetic problems in the developing baby. It can also be used for sex determination.
Amniocentesis is a diagnostic test, not a screening test, is 99% accurate for diagnosing Down syndrome and is usually done between 14 and 20 weeks.
Usually, it is done early in pregnancy to diagnose chromosomal and other fetal problems such as:
- Down syndrome (trisomy 21) (genetic amniocentesis)
- Trisomy 13 (genetic amniocentesis)
- Trisomy 18 (genetic amniocentesis)
- Fragile X (genetic amniocentesis)
- Rare, inherited metabolic disorders(genetic amniocentesis)
- Neural tube defects (anencephaly and spina bifida) by alpha-fetoprotein levels (genetic amniocentesis)
- Genetic amniocentesis is generally offered when the test results might have a significant impact on the management of the pregnancy — or your desire to continue the pregnancy.
- With maturity amniocentesis, a sample of amniotic fluid is tested to determine whether the baby’s lungs are mature enough for birth.
- Occasionally, amniocentesis is used to evaluate a baby for infection or other illness.
- Rarely, amniocentesis is used to decrease the volume of amniotic fluid.
- Amniocentesis is most often offered to women who are at increased risk for bearing a child with birth defects. This includes women who:
- Will be 35 or older when they give birth
- Had a screening test result that shows there may be a birth defect or other problem
- Have had babies with birth defects in other pregnancies
- Have a family history of genetic disorders
How it is performed
During this procedure, a small amount of fluid from the sac around the baby in the womb (uterus) is removed and is most often done in a doctor’s office or medical center. But first, a pregnancy ultrasound (with a full bladder) may be done in order to help the health care provider see where the baby is in your womb. Also, blood may be taken to find out your blood type and Rh factor. You may get a shot of medicine called RhoGAM if you are Rh negative.
Before the procedure, a local anesthetic can be given to the mother in order to relieve the pain felt during the insertion of the needle used to withdraw the fluid. Sometimes, the medicine is given through a shot in the skin on the belly area. When the anesthetic takes effect, a needle is usually inserted through the mother’s abdominal wall, then through the wall of the uterus, and finally into the amniotic sac. With the aid of ultrasound-guidance, a physician punctures the sac in an area away from the fetus and extracts approximately 20ml of amniotic fluid.
The fluid is then sent to a laboratory. Testing may include:
- Genetic studies
- Measurement of alpha-fetoprotein (AFP) levels
- Results come back in about 2 weeks.
This procedure may also be done at times later in pregnancy in order to diagnose infection, to check to see if the baby’s lungs are developed and ready for delivery, and to remove excess fluid from around the baby when an abnormally high amount of fluid is made (polyhydramnios).
Risks when performing this procedure are minimal, but may include:
- Infection or injury to the baby (Rarely, amniocentesis might trigger a uterine infection)
- Miscarriage (Research suggests that the risk of miscarriage is higher for amniocentesis done before 15 weeks of pregnancy);
- Leaking of amniotic fluid (Rarely, amniotic fluid leaks through the vagina after amniocentesis)
- Needle injury (during amniocentesis the baby might move an arm or leg into the path of the needle).
- RH sensitization (Rarely, amniocentesis might cause the baby’s blood cells to enter the mother’s bloodstream)
- Vaginal bleeding
So, the test is done and now you’re waiting for the results. Normal results reveal “no genetic or chromosome problems seen in the baby” and that Bilirubin and alpha fetoprotein levels appear normal. However, even with normal results after an amniocentesis, a baby may still have other types of birth defects.
An abnormal result may mean the baby has a gene or chromosome problem (Down syndrome or other abnormalities) and birth defects may be present that involve the spine or brain (spina bifida).