Triploidy is a chromosome abnormality that occurs when there is an extra set of chromosomes present in each cell. Most pregnancies affected by triploidy are lost through early miscarriage. However, reports exist of some affected babies living up to five months. Those that survive are often mosaic. The signs and symptoms associated with triploidy vary but may include a variety of birth defects and an unusually small size. This condition does not run in families and is not associated with maternal or paternal age. Treatment is based on the signs and symptoms present in each person. The disease is Monarch Disease Ontology entry MONDO_0018067 (triploidy).