This book is based on the research that was carried out on adolescent females who were in their gestation period, all of them natives of the district of Saman (at an altitude of 3830 m.a.s.l.) in the department of Puno in Peru. In this research we evaluated the clinical characteristics of gingivitis in relation to adolescent pregnancy. During the process, the oral cavity of each patient was inspected, observing in them the different clinical characteristics of the gum, place where this disease manifests itself and according to the territorial and geographical altitude in which these people are, different manifestations were observed that were the reason for the study. With the elaboration of this investigation a precedent of a study carried out in the high Andean zone of the country was left and the beginning for next related studies, for the benefit of the public health and the pertinent institutions.