High Versus Free Humidity Incubators; A Randomized Clinical Trial

When the IVF started the majority of incubators designed to support high humidity because the designers and IVF specialists believed that the humidity will maintain stable ph and Temp. Recent reports suggest that humidity is recommended and the others suggest no difference So we decide to go for this RCT. Nevertheless; high humidity is maintained in vivo (uterus and fallopian tubes) due to the fluid content and stable body temperatures at 37°C. David McCulloch reported 15% reduction of the miscarriage rate after changing the humidity from 76% to 100% (Textbook of Assisted Reproductive Techniques: Laboratory Perspectives, Fourth Edition). Some embryologists claim that the humidity free incubators may increase the chance of chemical pregnancy and early fetal loss (Private center IbnSina IVF, Sohag, Egypt. unpublished data). This observations are never tested in a well designed randomized clinical trial (RCT) to eliminate the probability of chance and to reach a solid evidence. The question that should be asked : is high humidity culture should be applied or there is no difference between dry and high humidity culture conditions?