Approximately 7.5% of all conceptions have a chromosomal abnormality, most of which are not compatible with survival or live birth.

Chromosome abnormalities are identified in 50% of early spontaneous abortuses and in 5% of stillbirths and infants who die in the immediate postnatal period. Even in live-born infants, the frequency is approximately 0.5% to 1.0%.

Types

 chromosomal numerical anomalies
 chromosomal structural anomalies (chromosomal rearrangements)

Consequences

 maldevelopment

• malformative syndromes

 tumors