Steer P J
Baillieres Clin Endocrinol Metab. 1990 Jun;4(2):333-49. doi: 10.1016/s0950-351x(05)80054-0.
Current evidence suggests that oestrogens, progesterone, relaxin, the prostaglandins, and oxytocin are all hormones concerned to a major degree with the onset and maintenance of parturition. Oestrogens, relaxin, and the prostaglandins are particularly involved with cervical ripening, while prostaglandins, progesterone and oxytocin are more involved in regulating myometrial contractility. Catecholamines may also have some regulatory function in relation to uterine contractions. Progesterone dominance during pregnancy is associated with a firm closed cervix, few myometrial gap junctions, low calcium levels in the cells, and a quiescent myometrium. At term, a change in the oestrogen/progesterone balance favours cervical ripening and increased uterine activity. Of particular importance at the level of the muscle cell are changes in the number of oxytocin receptors; a complex interaction between cAMP and phosphoinositide metabolism governs the intracellular level of calcium, thus regulating contractile activity.
目前的证据表明，雌激素、孕酮、松弛素、前列腺素和催产素都是在很大程度上与分娩的发动和维持相关的激素。雌激素、松弛素和前列腺素尤其与宫颈成熟有关，而前列腺素、孕酮和催产素则更多地参与调节子宫肌层的收缩性。儿茶酚胺可能也对子宫收缩具有某些调节功能。孕期孕酮占主导与宫颈紧闭、子宫肌层的缝隙连接较少、细胞内钙水平较低以及子宫肌层静止有关。足月时，雌激素/孕酮平衡的改变有利于宫颈成熟和子宫活动增加。在肌细胞水平特别重要的是催产素受体数量的变化；环磷酸腺苷（cAMP）和磷酸肌醇代谢之间的复杂相互作用控制着细胞内的钙水平，从而调节收缩活动。
