Amniocentesis is an optional procedure that can check for certain congenital abnormalities and genetic conditions in a developing fetus.
When there is a higher likelihood that the baby may have a congenital or genetic condition, a pregnant woman may request amniocentesis.
Or, a doctor may recommend the procedure later in pregnancy to check on the health of the baby and ensure that the right amount of fluid surrounds it in the womb.
Doctors generally consider amniocentesis safe, but it is an invasive procedure, and it carries risks. It is important to discuss these thoroughly with the doctor before deciding to undergo the procedure.
Below, we explore the definition, uses, and risks of amniocentesis.
Amniocentesis is an optional procedure. Healthcare providers tend only to perform it if the woman requests it and there is a higher likelihood of certain health issues affecting the fetus.
The procedure involves inserting a small needle through the abdomen and into the amniotic sac. The doctor or technician extracts a small sample of amniotic fluid through the needle and sends it to a lab for analysis.
The results of amniocentesis can help the doctor diagnose congenital disabilities or genetic conditions in the fetus.
According to the Children’s Hospital of Philadelphia, a doctor typically performs amniocentesis between the 15th and 20th weeks of pregnancy.
A doctor may recommend amniocentesis if:
- The woman will be 35 or older at the time of delivery.
- There is a family history of congenital disabilities or genetic disorders.
- Prenatal screening tests have given abnormal results.
- The woman has a child with a congenital disability or genetic condition.
In addition, a doctor may recommend amniocentesis later in pregnancy to:
- check on the baby’s lung development
- treat polyhydramnios — the medical term for too much fluid surrounding the baby
- test for other health conditions, such as anemia, that the doctor can treat while the baby is still in the womb
Amniocentesis only takes a few minutes. The procedure typically goes as follows:
- The woman lies on her back while a doctor or technician spreads gel over her abdomen.
- The healthcare provider uses ultrasound to find the fetus and placenta.
- They clean a small section of skin and, using the ultrasound imaging as a guide, insert a long, thin needle into the abdomen.
- They extract a small sample of fluid and remove the needle.
- They may also check the vital signs of the fetus, including the heartbeat.
Usually, the healthcare provider then sends the sample to a lab for analysis.
When the doctor’s office sends the sample to a lab, the results can take about 2 weeks to come back. Depending on the lab, it may send the results to the woman or the doctor’s office.
The doctor will review the results and explain what they mean. They can answer any questions and explain any professional terminology.
If the baby has certain health issues, the doctor may be able to treat these during the pregnancy.
The results of amniocentesis can influence whether a woman chooses to proceed with the pregnancy. A woman may decide to have an abortion, to give the baby up for adoption, or to start making preparations for any extra needs that the baby may have.
The doctor can provide information and guidance about each of these options.
Amniocentesis is an accurate procedure. According to the Dartmouth-Hitchcock health system:
- For Down syndrome and trisomy 18, amniocentesis results are more than 99% accurate.
- For open neural tube abnormalities, the results are about 98% accurate.
- Accuracy in detecting other genetic conditions varies.
In rare cases, the sample may not produce identifiable or conclusive results. If this occurs, the woman may choose to undergo the procedure again.
The cost of amniocentesis can vary, depending on where the woman lives and the healthcare provider.
Most insurance carriers tend to cover amniocentesis and other prenatal testing, but a referral may be necessary.
Some insurance companies only cover the procedure when the pregnancy carries significant risks.
Overall, it is important to check whether amniocentesis is covered before deciding to undergo the procedure.
There are some risks associated with amniocentesis. Discuss these carefully with the doctor before the procedure.
According to the March of Dimes, about 1 in 200 amniocentesis procedures result in pregnancy loss.
In addition, amniocentesis may cause:
- cramping, leaking fluid, or spotting (in 1–2% of cases)
- uterine infection
- an infection passing to the baby
- problems with the baby’s blood
A woman should tell her doctor if she experiences any of the following after amniocentesis:
- leaking fluid or blood from the vagina
- abdominal cramping that lasts longer than a few hours
- redness or swelling at the insertion site
- changes in fetal movement
- a fever
Amniocentesis is a procedure that can check for genetic disorders or congenital disabilities in a developing fetus. It is optional, but a doctor may recommend it.
Amniocentesis, like all invasive procedures, comes with risks. Discuss these, and the results, thoroughly with the doctor.
Hearing the results of amniocentesis can be difficult, and it may be a good idea to have a trusted friend or family member at the appointment for support.
When deciding whether to undergo amniocentesis, it is important to discuss the risks, accuracy, and options with the doctor in detail.