Este trabajo comparo la incidencia de desgarros perineales en pacientes nuliparas sometidas a episiotomia mediana rutinaria y selectiva. Durante marzo de 1997 Y febrero de 1998, los autores seleccionaron aleatoriamente pacientes nuliparas atendidas en el Hospital General de Medellin (HGM), practicando episiotomia mediana rutinaria o selectiva durante el periodo de expulsivo del parto. Se presentan los resultados preliminares de 47 pacientes que recibieron episiotomia rutinaria y 53 selectiva. En las selectivas hubo 23 (43.4 %) episiotomias. Se observo desgarro perineal en 20 (43 %) del grupo rutinario y en 33 (62 %) de las selectivas, sin diferencias estadisticamente significativas (Ch] = 3.85 p = 0.04985387). Se presento 8.6 % desgarros perineales grado 1 y II en las episiotomias rutinarias y 43 % de las selectivas (R.R = 0.20, Le. 95 % = 0.07 - 0.53). Los desgarros grado III y IV ocurrieron en 34 % del grupo de rutina y 18.9 % de las selectivas (R.R = 1.80, IC 95 % = 0.91 - 3.58). En su conjunto los grupos no presentaron diferencias estadisticamente significativas (Ch] = 3.85 Y P = 0.04985387). 13 de las 23 episiotomias selectivas se realizaron por inminencia de desgarro perineal. Se concluye que hasta la fecha no hay diferencias en la incidencia de desgarros perineales utilizando episiotomia mediana rutinaria o selectiva. Igualmente no se evidencian diferencias significativas en la incidencia de desgarros leves (1 y 11) Y graves (Ill y IV) con episiotomia mediana rutinaria o selectiva. ABSTRACT This Study compared the incidence 01 perineum lacerations among nulligravidas patients who were subjected to routine midline episiotomy or selective midline episiotomy, during the time comprehended between March 011997 to February 011998 at the Hospital General 01 Medellin HGM). 47 patients were in the routine midline episiotomy group and 53 patients were in the selective episiotomy group, in the later group 23 patients (23.4%) received episiotomy and it was lounded 20 patients (43%) with perineum laceration. 33 patients (62%) had perineum laceration in the selective episiotomy group. lt isn significant statistic difference (CIi = 3.85 p = 0.04985387). There were 8.6% 01 perineum lacerations grade 1 or 1I in the routine episiotomy group and 43% in the selective episiotomy group (RR= 0.20, C195% = 0.07 - 0.53). The grade III and IV perineum lacerations were in 34% patients in the routine episiotomy group, and 18.9% patients in the selective episiotomy group (RR = 1.80. C195% = 0.91 - 3.58). There weren ~ significant statistic differences between the group (CIi= 3.85 p= 0.04985387). 13 procedures Irom the selective episiotomy group were done because imminent perineum laceration. until today we coud not~ find differences in the incidence 01 perineum lacerations using midline episiotomy or selective episiotomy, neither we observed significant differences in the incidence 01 grade 1 or 1I perineum lacerations and grade III or IV ones with routine or selective episiotomy.