Changes in appearance of amniotic fluid during pregnancy - the macroscore.

During the first two trimesters of pregnancy the amniotic fluid is clear and yellow; during the third trimester the amniotic fluid becomes colourless; then, approximately from the 33rd-34rd week on, cloudiness and flocculation occur, at first very slowly, after the 36th-37th week steadily faster (Tab. I). At term, the amniotic fluid is moderately cloudy and contains a moderate number of flakes of vernix.