Peristaltic flow in a tapered channel: application to embryo transport within the uterine cavity

Cyclic uterine peristalsis plays a central role in assisting the transport of sperm to the fallopian tube and later in the conception process in trans porting the embryo to a fundal site for implantation. Fulfillment of these essential events within the time limits of fertilization and implantation d epends on concomitant intrauterine fluid motion induced by uterine wall mot ility. A model of wall-induced fluid flow within a finite tapered two-dimen sional channel was developed to simulate intrauterine fluid flow pattern an d transport phenomena due to symmetric and asymmetric wall displacements. T he analysis showed that the transport phenomena are strongly dependent on t he phase shift of wall displacement and the angle between the walls. The ve locities, flow rates, pressure and the axial transport of massless particle s are reduced to zero when contractions are completely out of phase. Cases of reflux and trapping in a tapered channel are discussed for the first tim e. The reflux phenomenon is most likely to occur when wall motility is asym metric, especially when the angle between the walls increases, while trappi ng is enhanced as the asymmetric motility and the angle between the channel walls decrease. The relevance of the results to intrauterine fluid transpo rt phenomena, embryo transfer and hydrosalpinx was explored. (C) 2001 IPEM. Published by Elsevier Science Ltd. All rights reserved.