THE DYNAMICS OF RAPID SPERM TRANSPORT THROUGH THE FEMALE GENITAL-TRACT - EVIDENCE FROM VAGINAL SONOGRAPHY OF UTERINE PERISTALSIS AND HYSTEROSALPINGOSCINTIGRAPHY

Vaginal ultrasonography of uterine peristalsis during the follicular p hase of the menstrual cycle demonstrates an increasing frequency and i ntensity of subendometrial and myometrial peristaltic waves as the fol licular phase progresses, During this time the numbers of contraction waves ,vith a fundo-cervical direction decrease considerably in favour of waves of contraction with a cervico-fundal direction, There is evi dence that rapid sperm transport through the female genital tract is p assive and is provided by these uterine contractions. Using hysterosal pingoscintigraphy, rapid sperm transport was studied by placing techne tium-labelled albumin macrospheres of sperm size at the external os of the uterine cervix and following their path through the female genita l tract, Ascension of the macrospheres occurred immediately following deposition at the external os of the cervix, As early as 1 min thereaf ter, the macrospheres had reached the intramural and isthmical part of the tube, Quantitatively, the extent of ascension increased with prog ression of the follicular phase, While only a few macrospheres entered the uterine cavity and even fewer the tubes during the early follicul ar phase, the proportion of macrospheres that entered the uterine cavi ty increased dramatically during the mid-follicular phase despite cont inuing limited entry into the tube, During the late follicular phase t here was considerable ascension of the macrospheres which was directed preferentially into the tube ipsilateral to the dominant follicle. Th ese data indicate that rapid transport of the spermatozoa through the female genital tract is under the endocrine control of the dominant fo llicle, ensuring the preferential accumulation of spermatozoa at the s ite of fertilization.