546 THE PHYSIOLOGY OF REPRODUCTION 



is put to the breast, a fact which seems to indicate a nervous 

 connection between the uterus and the mammary glands. 

 In primiparous women the tonicity of the puerperal uterus is 

 usually greater than in multiparous ones, so that the uterus is 

 capable of remaining during this period in a state of almost 

 uninterrupted retraction unless blood clots or other foreign 

 bodies are present in the cavity, in which case the organ under- 

 goes movements in attempting to expel them. 



This tonic retraction of the uterus is an important factor in 

 closing the blood sinuses, and so preventing bleeding. If, owing 

 to any circumstance, the normal contraction and retraction of 

 the uterus are interfered with, post-partum haemorrhage is 

 liable to occur. This is not infrequently the case with white 

 women who have migrated to the tropics, or with ill-nourished 

 women in the slums, in whom, owing apparently to an inefficiency 

 in the uterine nerve supply, the organ tends to become inert. 1 

 It follows from what has been said that multiparous women 

 are more liable to post-partum haemorrhage than primiparous 

 ones. 2 



According to Longridge the anaemic condition of the normal 

 puerperal uterus is due partly to the effacement of the ovarian 

 and uterine arteries which occurs when the uterus contracts. 

 ' The reality of this occurrence is supported by an observation 

 which can be made in many cases of Caesarian section ; in this 

 operation it is noticed that as long as the uterus remains outside 

 the abdomen it tends to bleed, but that as soon as it is dropped 

 back bleeding ceases. It is not the warmth of the abdominal 

 cavity that checks the bleeding, since it may continue when the 

 uterus is wrapped in warm towels outside the abdomen. But 

 the mere fact of pulling up the uterus opens out the concertina, 

 as it were, and allows blood to flow through the arteries. If 

 the bladder is full at the end of labour, the uterus is pushed 



1 Longridge, The Puerperium, London, 1906. 



2 Longridge has pointed out, however, that the amount of post-partum 

 discharge in multipane is not as a rule in proportion to the severity 

 of the "after-pains," and consequently that the latter cannot be ascribed 

 simply to defective retraction on the part of the uterus. He suggests, 

 therefore, that the " after-pains" in multipart are largely due to the uterus 

 suffering from cramp resulting from the excessive exertion involved in dis- 

 charging the child. 



