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Capacitation, the Acrosome Reaction, and Motility in Mammalian Sperm
Published in Claude Gagnon, Controls of Sperm Motility, 2020
Susan S. Suarez, John W. Pollard
After passing through the cervix, spermatozoa traverse the length of the uterus, either by their own flagellar activity or by some action of the uterus itself. At the anterior end of the uterus or uterine horns, they enter the oviducts through the uterotubal junction. The junction and/or the caudal portion of the oviductal isthmus apparently acts as a sperm reservoir, preventing most of the spermatozoa from continuing on to the ampulla.44 Although the uterine environment is capable of fully capacitating spermatozoa,45 the primary site for the completion of capacitation is thought to be the oviduct.33 In fact, capacitation may not even be initiated in spermatozoa destined to fertilize until they enter the oviduct, especially in species having uterine insemination sites. In some species, spermatozoa have been observed to be immobilized in the caudal isthmus.12,46 Perhaps they are inhibited from continuing or completing capacitation at this time as well. Capacitation could resume when they are released or release themselves from the isthmic reservoir. The isthmic sperm reservoir is discussed in greater detail in the chapter in this volume by Overstreet and Katz.
Acquired uterine conditions, reproductive surgery, and recurrent implantation failure
Published in Efstratios M. Kolibianakis, Christos A. Venetis, Recurrent Implantation Failure, 2019
Dimitra Aivazi, Eleni Tsakalidou, Grigoris F. Grimbizis
Mechanical interference affecting sperm transportation, as well as embryo implantation, is in line with the hypothesis that the location of EP may influence pregnancy rate; Yanaihara et al. showed that removal of EP located near the utero-tubal junction provides the best results on fertility compared with other locations.52
Gynecologic Microsurgery
Published in Waldemar L. Olszewski, CRC Handbook of Microsurgery, 2019
The uterotubal junction is not crucial because patients can conceive following tubal implantation in either the cornual region or posterior uterine wall. Since conception can occur following either tubal implantation of the ampulla or anastomosis of ampullary interstitial segments, the isthmus is not required. Successful pregnancy can follow a salpingoneostomy, an operation in which no fimbria are present. The ampulla is probably crucial because isthmic salpingoneostomy never succeeds.
Zooming in on the endometrial factor of recurrent implantation failure
Published in Human Fertility, 2022
Chibuzor Ifenatuoha, Babatunde Okewale
The mechanism by which EPs contribute to subfertility and RIF is poorly understood, but it may be due to mechanical interference imposed on sperm movement, embryo implantation, or may be due to the high production of glycodelin by the polyps (Al Chami & Saridogan, 2017). An investigation involving 230 subfertile women who were undergoing hysteroscopy and polypectomy, showed that the location of EPs may disturb the flow of normal reproductive processes like the transport of sperm, implantation of the embryo or early development of pregnancy (Fatemi et al., 2010). The results obtained from this study, 6 months after the surgery, showed that the pregnancy rates for EPs removed from the uterotubal junction was 57.4%, 40.3% for multiple polyps, and were 28.5%, 18.8% and 14.8% for EPs removed from the posterior, lateral, and anterior walls respectively (Fatemi et al., 2010). A number of other studies also support the claim that the removal of EPs will improve the outcome for natural conception and ART (Al Chami & Saridogan, 2017; Gregoriou et al., 2009). A study showed that the sizes of the EPs do not correlate with the pregnancy outcome (de Ziegler, 2009).
Hysteroscopic evaluation of tubal peristaltic dysfunction in unexplained infertility
Published in Journal of Obstetrics and Gynaecology, 2018
Burak Yücel, Emine Demirel, Sefa Kelekci, Osama Shawki
To achieve pregnancy, in addition to patency, two paradoxical peristaltic movements occur in the tubes. First, muscular contractions of the distal part of tube and second, the cilia of its inner lining, move the egg toward the interstitial segment of the tube. This segment acts like a muscle sphincter and prevents the egg from being released into the uterus until it is ready for implantation (Darwish 2015). Two distinct types of contractions have been described in the oviductal smooth muscle: sustained tonic contractions and frequent brief episodic contractions. Sustained tonic contractions are localised to the ampullary-isthmic junction and the utero-tubal junction and probably serve as a sphincter. This mechanism transiently arrests at the time of the tubal transport of gametes and embryos. During this transient arrest, the proximal part of the tube expresses peristalsis to attract sperms to the site of fertilisation. On the other hand, the other type of contractions in the form of frequent but brief spells of contractions will mix the tubal passengers including the gametes and embryo with the tubal fluid (Maia and Coutinho 1970; Kunz et al. 1997).
Removal of uterine polyps: clinical management and surgical approach
Published in Climacteric, 2020
A. Ludwin, S. R. Lindheim, R. Booth, I. Ludwin
The etiology related to infertility is not entirely understood. Endometrial polyps are found most commonly in the posterior uterine wall, uterine fundus, and uterotubal junction. They range in size from millimeters to lesions that occupy the entire endometrial cavity36. A uterotubal polyp may lead to loss of function of the ostium and could affect sperm migration, with 57.4% of women achieving pregnancy within 6 months after polypectomy8,36. Interestingly, Ben-Nagi et al. noted that improvement in pregnancy rates following hysteroscopic polypectomy was independent of polyp size, suggesting not simply mechanical but possibly biochemical interference with implantation posed by the presence of an endometrial polyp37.