Changes in cervical compliance at parturition independent of uterine activity

Spontaneous motility of the cervix in cyclic and ovariectomized ewes and changes induced by exogenous hormones

“…It appears that the cervix contains the richest innervation of any part of the human uterus (Krantz & Phillips, 1962) and isolated strips of human (Najak, Hillier & Karim, 1970) and sheep (Edqvist, Einarsson, Gustafsson, Linde & Undell, 1975) cervix exhibit spontaneous contractility in vitro and responsiveness to different drugs. In addition, the independence of uterine and cervical motility in vivo has been demonstrated in ruminants (Chen, MacDonald & Hawes, 1966;Fitzpatrick, 1957; Stys, Clewell & Meschia, 1978). Stress conditions or general anaesthesia impair the passage of spermatozoa in the ewe (Brinsfield & Hawk, 1969).…”

The effects of oestradiol benzoate, progesterone, relaxin and ovariectomy on cervical extensibility in the late pregnant rat

“…Oestrogens alone and in combination with progesterone and/or relaxin can increase cervical size and produce small increases in cervical extensibility in non-pregnant and mid-pregnant, ovariectomized rats (Kroc, Steinetz & Beach, 1959;Cullen & Harkness, 1960;Zarrow & Yochim, 1961). Cervical dilatation in the pre-term sheep following fetal dexamethasone infusions was said to be inhibited by progesterone injections (Liggins, 1973) although this has not been supported by more quantitative measurements (Stys, Clewell & Meschia, 1978).…”

Pregnancy-related changes in rat cervical glycosaminoglycans

“…More recent evidence suggests, however, that softening results instead from intrinsic alterations in the extracellular components of the stroma (Danforth et al, 1960(Danforth et al, , 1974Zarrow & Yochim, 1961;Buckingham et al, 1962;Cretius et al, 1966;Bryant et al, 1968;Kondo, 1972;Danforth & Buckingham, 1973;Rimmer, 1973; Maillot & Zimmermann, 1976;Kleissl et al, 1978). Indeed, initiation of cervical softening and onset of uterine contractions may, at least in some species, be under independent hormonal control (Stys et al, 1978).…”