Epidemiology of triploidy in a population-based birth defects registry, Hawaii, 1986-1999

Triploidy is a highly lethal chromosomal abnormality with few fetuses surviving to term. Triploidy has not been extensively studied using data from a population-based birth defect registry. This investigation examined the epidemiology of triploidy using data from the Hawaii Birth Defects Program (HBDP) and compared its findings with the literature. Of the 38 identified cases of triploidy delivered in Hawaii during 1986-1999, 31 (82%) were early fetal deaths, 3 (8%) late fetal deaths, and 4 (11%) elective terminations. The distribution of cases by sex chromosome combination was 15 (39%) XXX, 22 (58%) XXY, and 1 (3%) XYY. Triploidy was prenatally diagnosed in eight (21%) of the cases, of which four were electively terminated, two resulted in early fetal death, and two resulted in late fetal death. The detected triploidy prevalence in 1993-1999 was higher than the prevalence in 1986-1992, although the difference was not statistically significant (rate ratio (RR) 1.20, 95% confidence interval (CI) 0.73-1.86). The detected triploidy prevalence for maternal age of 35 years or greater was significantly higher than the prevalence for maternal age less than 35 years (RR 4.07, 95% CI 2.22-6.83). In spite of under detection of cases, many aspects of the epidemiology of triploidy identified in a population-based birth defects registry were consistent with that reported in the literature.