Prenatal diagnosis is performing chromosome analysis for diseases or conditions in a fetus or embryo before birth. Some criteria are required to perform the analysis. Prenatal diagnosis is performed to detect presence or absence of structural or numerical abnormalities in chromosomes.

Prenatal Cytogenetic Samples:
Amniotic Fluid: It involves cells of fetal origin. Amniotic fluid consists of the cells of baby’s skin, respiration system, digestive system and excretory system and mostly baby’s urine.
CVS (Chorionic Villus Sampling):
Chorionic villus sampling (CVS) is the removal of a small piece of placenta tissue (chorionic villi) from the uterus during early pregnancy to screen the baby for genetic defects. CVS usually takes place 10-12 weeks after the last period, earlier than amniocentesis.
Cordocentesis:
Cordocentesis, is a diagnostic genetic test that examines blood from the fetal umbilical cord to detect fetal abnormalitie. An advanced imaging ultrasound determines the location where the umbilical cord inserts into the placenta. The ultrasound guides a thin needle through the abdomen and uterine walls to the umbilical cord. Cordocentesis is performed between 19-21 weeks into pregnancy.

Prenatal Diagnosis Indications:
• Maternal age
• Having a child with de novo chromosomal abnormality
• Parents with structural chromosome abnormality
• Biochemical or genetic disease which is diagnosed with DNA analysis in family history
• An X-linked disease history which doesn’t have a specific prenatal diagnosis analysis
• Risk of neural tube defects
• Abnormal ultrasound scan or maternal serum scanning

Chromosome Analysis Phases in Amniotic Fluid:
• Cell Culture
• Cell Fixation
• Cell Painting
• Analysis