As soon as physicians and surgeons turned to midwifery, they claimed to transform this field into a science. They pretended to have better knowledge than ignorant midwives. All questions concerning the diagnosis of pregnancy, however, were among the fields where the knowledge of the would-be specialists of the female body remained highly insecure for a long time. This article analyzes more than 1,300 medical case histories from the hospital diaries at the maternity of the hospital in the University of Göttingen, hand-written by the director and professor of obstetrics, Friedrich Benjamin Osiander (1792 – 1822). The focus is on the negotiations between pregnant women and the doctor in reaching a diagnosis. To what extent did the obstetrician rely on what the women told him, or by what means did he try to establish an independent knowledge of his own?