THE HORMONES IN HUMAN REPRODUCTION 



taneous abortion of the embryo or fetus ("miscarriage"). 

 About one pregnancy in three terminates prematurely, ac- 

 cording to generally accepted figures.^ These accidents have 

 many causes. Sometimes the embryo is itself unhealthy, 

 through some mischance of heredity or development, like a 

 seedling plant that will not grow. Sometimes illness or acci- 

 dent to the mother upsets the course of events. Sometimes, we 

 may suppose, the hormones go wrong. Perhaps the supply of 

 progesterone from the corpus luteum or placenta is not ade- 

 quate. In such cases it might conceivably be useful to supply 

 the hormone by injection, thus making up the lack. The main 

 difficulty at present is to diagnose such cases in time to treat 

 them. 



There is another way in which progesterone might help. 

 No matter what the cause of an abortion, it is always accom- 

 panied by spasmodic contractions of the uterus, trying to get 

 rid of its burden. Sometimes, we think, the contractions come 

 first, as the result of injury or illness, and dislodge a normal 

 embryo. We have seen that progesterone will quiet the uterine 

 muscle; by reason of this, we may hope that it will help to 

 steady the uterus in the case of a threatening abortion. With 

 these thoughts in mind, the doctor tries progesterone in the 

 face of such a disaster. Sometimes the pregnancy goes on, 

 sometimes not. How can he tell whether his hormone worked 

 the cure ? His case records are not altogether helpful, for no 

 two cases are alike; and what is more, the physician in his 

 anxiety generally tries two or three remedial measures at 

 once, any one of which might have been responsible. If he 

 controls a large clinic with many such patients, he can use 

 the treatment on alternate cases only until he is satisfied 

 which group does better. By this method, while the physician 



3 This statement need cause no alarm to any prospective mother who 

 happens to read it. Once pregnancy is past the first weeks and under 

 medical care, it goes safely on in an overwhelming majority of cases. 

 The figure of one loss in three includes many pregnancies of the earliest 

 weeks, and even some that occur so early as to be recognized only by 

 microscopic methods. 



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