Amniocentesis is a medical term used when doctors remove fluid from the uterus of a pregnant woman for testing. The fluid withdrawn is called amniotic fluid; its purpose is to protect the unborn child. This fluid contains fetal cells and different chemicals from the baby.
According to the Mayo Clinic, an amniocentesis can be done for different reasons:
1. Genetic amniocentesis – as the name implies, this type of testing concentrates on your baby’s genetic makeup. Usually, doctors will suggest a genetic amniocentesis when a patient has received abnormal results from a prenatal screening (to confirm or rule out a diagnosis), the patient has had a pregnancy with Down syndrome or neural tube defects (abnormality to the brain or spinal cord), if the patient is 35 years or older, and/or if the patient or her partner has a family history of a specific genetic disorder.
2. Maturity amniocentesis – this type of procedure indicates if the baby is physically ready to be born – particularly in the lungs. If preterm labor is an issue, it becomes highly important to confirm whether the baby’s lungs are strong enough for birth.
3. Other reasons – there are several other reasons why an amniocentesis may be done as well:
• Evaluate a baby for infection or other illness
• Decrease the volume of amniotic fluid
• Diagnose a uterine infection
• Evaluate the severity of anemia in babies who have Rh disease — 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
Know the Risks
With almost every procedure, there are risks. Please don’t be shy about asking your doctor about the risk of this procedure if she/he has not been forthcoming.
Risks as indicated by the Mayo Clinic:
Miscarriage – especially in the second trimester, there is a "slight" risk of miscarriage when an amniocentesis is done.
Cramping and vaginal bleeding – some mothers experience cramps and bleeding after this procedure.
Needle injury – injuries are rare, but sometimes babies move their arm or leg and are subsequently injured by the needle used during this procedure.