Obstetric Services


Who Should Have Amniocentesis?

You and your doctor will decide whether the information provided by amniocentesis is important enough to warrant having the procedure done.  Amniocentesis may be recommended for the following patients:

  • Pregnant women age 35 or older.  There is a direct relationship between the mother's age and having a baby with Down Syndrome or Trisomy 21.  For women under 30, the chance is less than 1 in 1000, but at age 35 the risk increases to 1 in 720.  The risk continues to increase as maternal age increases.


  • Couples who have had a child with genetic disorder or certain other birth defects.  If either parent has had a child with a genetic abnormality, the chances are at least 1 in 100 that a subsequent child will have a birth defect associated with chromosomal abnormalities.


  • Couples who have a family history of chromosomal abnormalities.


  • Couples who have had a child with a neural tube defect.  If the fetus has spina bifida ("open spine") or anencephaly ("open skull"), the amniotic fluid will usually contain large amounts of alpha-fetoprotein (AFP).  The fluid withdrawn from the chromosomal analysis can be tested for the AFP level.

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