Does the color of amniotic fluid still matter?

Second trimester amniotic fluid (AF) is generally clear or very light yellow. We examined the color of 2,141 AF samples. Fifty-six specimens were brown, 35 were green. There were 71 samples with abnormal karyotype (3.46%). In the group with brown AF, there were 7 abnormal karyotypes out of 56 (12.5%). There was 1 case of aneuploidy out of the 35 green samples (2.86%). We conclude that green AF in the second trimester, absent any other findings, carries no special significance, but brown AF carries a fourfold increased incidence of chromosomal aneuploidy in patients undergoing genetic amniocentesis.