A new method for evaluating cervical penetrability using daily aspirated and stored cervical mucus.
Cervical mucus samples from 33 women undergoing fertility work-up and married to normospermic husbands were aspirated daily with a tuberculin syringe during the periovulatory period. Samples were transferred to polyethylene tubing, sealed, and stored at 4 degrees C for 7 to 14 days. In vitro sperm penetration tests were performed in each case, using only one sample of husband's semen with all of the mucus samples that were collected during one cycle. Preliminary studies with 50 samples of cervical mucus taken at random showed that no difference in physicochemical and penetrability properties existed between fresh mucus and mucus stored for 10 to 14 days. Very often the optimal penetrability of the cervical mucus occurred on unpredictable days. In contrast, many tests performed on days which would have been predetermined for in vivo postocital tests were poor; consequently, those in vivo tests would have been falsely interpreted as negative. This new test using daily aspirated and stored mucus, which is simple to perform, is valuable mainly because it may eliminate the false negative results of other penetration tests. In this way the diagnosis of a truly hostile cervix may be more accurate.