Reproductive performance in women with sex chromosome mosaicism

Among chromosomal analyses performed in 23 couples with a history of 2 or more spontaneous abortions, 5 women had mosaicism of the sex chromosomes, 46,XX/47,XXX, but all the men had normal 46,XY chromosomal complements. A review of the literature revealed that 75% of the fetuses of mothers with sex chromosome mosaicism were abnormal. Fifty percent of theses pregnancies ended in abortion and one third of the infants exhibited a chromosomal or physical abnormality. The possible effect of sex chromosome mosaicism on outcome of pregnancy is emphasized.