To establish a description of the psychiatric population of the Instituto Nacional de Perinatología (INPer), as well as of the exposed newborns to psychopharmacological treatment during the gestation.One hundred forty-six women were gathered, by means of serial files; 85 of them had an obstetric episode of high risk and 61 were assisted in the institution due to gynecological alterations. A clinical psychologist and a psychiatrist carried out, each one, an interview and the clinical history of all the women. Once the type diagnosis was determined (DSM-IV), they received psicotherapeutical, pharmacological or mixed treatment, until the resolution of the obstetric episode and the gathering of the neonatal data.The findings reported that the prevalence or mental disorders (DSM-IV) that are not adaptive at the INPer is 1.8%. The diagnostic distribution of the psychiatric population ranked in first place the affective disorders (63.7%), particularly major depression disorder (42.5%). These percentages correspond at the institutional total population's 1.19 and 0.79. As for the treatment type, 57 women received psychotherapy, 75 received psychopharmacological treatment and 14 received both treatments. The newborn babies of obstetric patients who received psychopharmacological treatment did not show differences in Apgar, weight, size, complications or obstetric resolution in comparison with patients who received psychotherapy and again with respect to institutional media.The prevalence found in the Institution is significantly inferior to that reported at a national and global level, due to the use of two diagnostic interviews by mental health specialists. The wrong use of the sieve is one of the reasons for overdiagnosis in mental health.