Reasons for Amniocentesis

Amniocentesis is most often done to see if there is an abnormality in your baby's genes (DNA). It can also be done to see if your baby is developing rightly.

Some things may make your doctor more concerned that there may be a problem:

• Mother is over 35 years old (at the time of delivery)
• Family history of chromosome abnormality
• Family history of inherited disorder
• Family history of neural tube defect (problems in spine and brain growth, such as spina bifida or anencephaly)
• To determine whether the baby's lungs are mature
• Abnormal results from earlier blood screening test, such as maternal serum alpha-fetoprotein (AFP)

Depending on your risk factors, the cells are tested for:

• Chromosome abnormalities-This testing detects most chromosome abnormalities. The results are usually ready within 14 days. Missing or extra chromosomes lead to physical birth defects and mental retardation . The most common is Down syndrome . This is caused by an extra #21 chromosome.
• Inherited genetic diseases-Test results are usually ready in 1-5 weeks. Examples include:
  • Tay-Sachs disease -most frequent in the Ashkenazi Jewish population
  • Cystic fibrosis -most frequent in Caucasians of northern European ancestry
  • Sickle cell disease -most frequent in the Black population