DYSTOCIA 305 



occasionally to prevent pregnancy. It may develop as a 

 simple hydrometra, in which case there will be no serious 

 effects upon the animal. 



Symptoms. Distention of the abdomen^ which becomes 

 pronounced and simulates pregnancy. Its persistence and 

 the absence of lactation differentiate it from pregnancy, 

 however. There are no general symptoms, no pain on manip- 

 ulation of the abdomen, and no change in the other parts 

 of the reproductive organs. 



Diagnosis. Hydrometra should not be confused with 

 pregnancy, tumors of the uterus, ascites, and pyometra. A 

 laparotomy may be necessary to make an accurate diagnosis. 



Prognosis. Favorable. 



Treatment. If due to an inguinal hernia, a surgical opera- 

 tion is necessary for relief. In other cases the entire uterus 

 together with the ovaries should be removed. 



DYSTOCIA. 



Definition. Difficult parturition. Dystocia is of frequent 

 occurrence in the bitch and cat. 



Etiology. Many etiological factors produce dystocia: 



1 . In a mechanical way we find numerous obstacles which 

 interfere with the expulsion of the fetus. 



(a) Lack of expelling power of the uterine muscles. This 

 is frequently due to general weakness, anemia, etc. 



(6) A narrow and undilatable pelvic canal, which is too 

 small for the fetus to pass. 



(c) Constriction of the os uteri, which prevents the pas- 

 sage of the fetus. 



(d) Torsion or displacement of the uterus, closing the 

 uterine exit. 



(e) Abnormal development of one or more of the fetuses 

 which are too large to pass through the pelvic canal. 



(/) Malpresentation or position of the fetus which pre- 

 vents it entering or passing through the pelvic canal. 



(g) Deformity or abnormality in the development of the 

 fetus. In some instances, as in hydrocephalus, ascites, or 

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