Another circumstance which influences to a certain extent the frequency of rupture of the uterus, is the rank of the patient: in private practice, especially among the better classes of society, it is an extremely rare occurrence; but in the lower grades of life several causes concur to render it more frequent. They are "much more exposed to falls, bruises, and other accidental injuries during pregnancy, in consequence of which the uterus may be either ruptured at the time they have sustained the violence, or may be so weakened in structure at some particular point, as readily to give way during its efforts to accomplish delivery. Lastly, they are more liable to fall into the hands of ignorant inexperienced midwives, who not unfrequently, with a view of expediting the process of delivery, rupture the membranes at an early period of the labour; in consequence of which, the firm unyielding head of the child is prematurely brought in contact with the passages, exciting by its pressure, swelling, inflammation, and an interrupted state of the circulation in the uterus and adjacent parts. In such a case should there unfortunately exist any disproportion between the parts of the mother and the head of the infant, or should proper measures not be employed to obviate distressing symptoms, and that the labour pains continue to recur with extreme violence, there is great risk of the uterus giving way, the laceration being of course most likely to occur at that part where the greatest pressure has been sustained." (M'Keever, _op. cit._ p. 3.) The _premonitory symptoms_ of rupture of the uterus are not always sufficient to warn us of the impending danger, for in many cases nothing unusual has occurred until the actual injury has been produced, and it has then been inferred by the alarming change observed in the patient's appearance. In many cases, especially where the muscular substance only of the uterus was torn, the pains have continued with a sufficient degree of power to expel the child; in others the mischief has been attended with so little suffering at the moment, and for the time with so little constitutional derangement, as to excite no suspicion, either on the part of the patient, or her attendant. "Farther, as on some occasions, the uterus has been known to give way during the very pain which effected the delivery of the child, instances of which may be found in the works of Crantz and Guillimeau." (_Ibid._ p. 15.)