Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Amniocentesis facts
- What is amniocentesis?
- Who is a candidate for amniocentesis?
- What does amniocentesis show?
- When should amniocentesis be performed?
- Is amniocentesis safe?
- Find a local Obstetrician-Gynecologist in your town
When should amniocentesis be performed?
For genetic testing, chromosome analysis, and evaluation of an abnormal AFP test, amniocentesis is usually performed between the 15th and the 20th weeks of pregnancy. There is a higher rate of miscarriage associated with amniocentesis that is performed earlier than the 15th week. There is no time limit as to how late in the pregnancy amniocentesis can be performed.
If amniocentesis is performed to determine fetal lung maturity, it is often done anywhere between the 32nd and 36th week of pregnancy. In women with diabetes, lung maturity testing may be done as late as the 39th week, because poorly controlled diabetes may delay fetal lung maturity.
Is amniocentesis safe?
Overall, amniocentesis is a safe procedure with the risk of fetal loss at generally less than 1%. According to the American College of Obstetricians and Gynecologists Practice Bulletin, there is a procedure-related rate of fetal loss ranging from 1/300 to 1/500 procedures.
Since there is the slight possibility of pregnancy loss from the procedure, amniocentesis should be performed only when clearly indicated and its benefits have been determined to outweigh any associated risks. Many parents ask for the procedure to "reassure" themselves that everything is perfect. It should be emphasized that an amniocentesis with normal results does not guarantee that the baby will not have a birth or genetic defect. Many birth defects cannot be detected by amniocentesis. Besides fetal loss, other risks associated with amniocentesis include bleeding, cramping and leakage of fluid from the vagina. These problems occur in about 1% of women undergoing the procedure, and generally resolve on their own. If these symptoms arise following the procedure, the woman is often advised to stop work and remain at bed rest until the symptoms cease. Subsequent activity will be proscribed by the doctor. Occasionally, the fetus is poked with the needle during the testing, but this is generally harmless.
Amniocentesis is a relatively safe and painless procedure that can provide helpful information. The procedure can be offered to selected women after reviewing the risks and benefits involved.
Medically reviewed by Mikio A Nihira, MD; American Board of Obstetrics & Gynecology
ACOG Practice Bulletin No. 88, Dec. 2007. Invasive Prenatal Testing for Aneuploidy. Obstet Gynecol. 2007 Dec;110(6):1459-67.
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