McNeilly A S, Tay C C, Glasier A
MRC Reproductive Biology Unit, University of Edinburgh, United Kingdom.
Ann N Y Acad Sci. 1994 Feb 18;709:145-55. doi: 10.1111/j.1749-6632.1994.tb30394.x.
Breastfeeding delays the resumption of normal ovarian cycles by disrupting the pattern of pulsatile release of GnRH from the hypothalamus and hence LH from the pituitary. The plasma concentrations of FSH during lactation are sufficient to induce follicle growth, but the inadequate pulsatile LH signal results in a reduced estradiol production by these follicles. When follicle growth and estradiol secretion does increase to normal, the suckling stimulus prevents the generation of a normal preovulatory LH surge and follicles either fail to rupture, or become atretic or cystic. Only when the suckling stimulus declines sufficiently to allow generation of a normal preovulatory LH surge to occur will ovulation take place with the formation of a corpus luteum of variable normality. Thus suckling delays the resumption of normal ovarian cyclicity by disrupting but not totally inhibiting, the normal pattern of release of GnRH by the hypothalamus. The mechanism of suckling-induced disruption of GnRH release remains unknown. It does not appear to involve prolactin, dopamine or opiates although a combination of these factors might be involved. Prolactin is the major hormone responsible for milk production and is present in sufficient quantities in almost all women to allow the establishment of normal lactation. Oxytocin is essential for milk let down and is susceptible to inhibition of release by stress. The successful initiation of lactation which would lead to the potential of utilizing breastfeeding as contraceptive may require more attention to be paid to the establishment of non-stress release of oxytocin.
母乳喂养通过扰乱下丘脑促性腺激素释放激素（GnRH）的脉冲式释放模式，进而影响垂体促黄体生成素（LH）的释放，从而延迟正常卵巢周期的恢复。哺乳期促卵泡生成素（FSH）的血浆浓度足以诱导卵泡生长，但LH脉冲信号不足导致这些卵泡产生的雌二醇减少。当卵泡生长和雌二醇分泌确实增加到正常水平时，哺乳刺激会阻止正常的排卵前LH峰的产生，卵泡要么无法破裂，要么发生闭锁或形成囊肿。只有当哺乳刺激充分减弱，使得正常的排卵前LH峰得以产生时，才会发生排卵并形成正常程度各异的黄体。因此，哺乳通过扰乱但并非完全抑制下丘脑GnRH的正常释放模式，延迟了正常卵巢周期性的恢复。哺乳引起GnRH释放紊乱的机制尚不清楚。虽然这些因素的组合可能参与其中，但似乎不涉及催乳素、多巴胺或阿片类物质。催乳素是负责乳汁分泌的主要激素，几乎所有女性体内都有足够量的催乳素以建立正常的泌乳。催产素对乳汁排出至关重要，且易受压力抑制其释放的影响。成功启动泌乳从而有可能将母乳喂养用作避孕方法，可能需要更加关注建立无压力状态下催产素的释放。
