Approximately 60% of all human spontaneous abortions during the first trimester of pregnancy are associated with chromosomal aberrations of the conceptus. Nearly 20% of these karyotypes are triploid,1,2 ie, 66 autosomes and three sex chromosomes. Hence, triploidy is one of the most frequent chromosome aberrations in human abortuses.
Developmental arrest followed by spontaneous abortion of the triploid conceptus most often occurs between three and six weeks after fertilization3; however, there are reports (summarized in references 4 and 5) of 31 cases of full triploidy that survived past 24 weeks of gestation. In a recent study of nearly 60,000 consecutive live-born infants, only one was a triploid.6 Though survival was usually limited to a few days7 in the 11 reported cases of pure triploidy, Fryns et al8 described a female infant who lived for two months after birth.
Triploid infants are reported to share a wide