Vaginosonography for recording of cycle-related myometrial contractions.

It has been recognized from experimental or invasive studies that the nonpregnant human uterus has an inherent contractibility. We used vaginosonography for imaging contractions of the inner third of the myometrium. The direction, frequency, and symmetry of contractions were noted. We studied 53 women and subdivided them into four groups based on the cycle phase. During menstruation we found contractions toward the cervix with irregular frequency varying between 1 and 3/min. In the periovulatory period we noted the highest frequency of 10/min of regular contractions toward the fundus. The results showed that active myometrial contractions can be detected sonographically throughout the whole menstrual cycle. Increased myometrial contractions toward the fundus in the periovulatory period may be involved in sperm transport to the tubes.