RENO, NEV. — Women who've had three spontaneous abortions before a current pregnancy have almost a 50% higher risk of carrying a fetus with aneuploidy than those who've never had a miscarriage, according to a large review of women who had undergone amniocentesis.
The aneuploidy rate becomes almost 2% in women who have had three pregnancy losses, Katherine Bianco, M.D., and associates wrote in a poster presentation at the annual meeting of the Society for Maternal-Fetal Medicine.
The study reviewed fetal karyotype analyses from 46,939 women who had been seen at a single prenatal diagnostic referral center between 1983 and 2003, 80% of whom were 35 years old or older, said Dr. Bianco of the department of obstetrics and gynecology at the University of California, San Francisco.
According to those records, women who could identify one previous spontaneous abortion were found to have fetuses with trisomy 13, 18, or 21 at a rate of 1.45%, compared with a rate of 1.10% for those who had not previously had a spontaneous abortion. Women who had two prior losses had a rate of 1.56%. Those with three prior losses had a rate of 1.70%, and a 2.18% rate of any aneuploidy.