Journal of Research in Medical Sciences1735-199512520071016The relation between endometrial thickness and pattern with pregnancy rate in infertile patients257261ENZibaZahiriDepartment of Obstetrics & Gynecology, Guilan University of Medical Science, Guilan, Iran.. drzibazahiri@yahoo.comSeideh HajarSharamiZahraAtrkar Roshan2006082620070520BACKGROUND: The usefulness of determination of endometrial thickness and pattern by ultrasound for pregnancy prediction has been confirmed as well as questioned in the literature. In an effort to help clarify this controversial issue and to find the relation between endometrial thickness and pattern and pregnancy rates, this study was undertaken. METHODS: This was a cross-sectional study. One thousand and thirty infertile couples with ovulatory factor infertility that underwent 1,030 cycles of induction of ovulation were included in this study. All patients charts were reviewed for endometrial thickness (<7, 7-14 and >14 mm) and pattern (triline versus homogenous) on the time of HCG administration. Age, duration of infertility and number of follicles were evaluated in all patients. Treatment outcome was clinical pregnancy rate. The SPSS 10 software and chi-square t-test and ANOVA were applied for statistical analysis. P<0.05 was determined as statistical significant. RESULTS: The overall pregnancy rate was 25.8% (266 from 1030). There was no statistically significant difference in pregnancy rates in three groups of endometrial thickness (<7, 7-14, >14 mm) and two groups of endometrial patterns (trilene and homogenous). CONCLUSIONS: This study showed that there is no significant relation between endometrial thickness and pattern and pregnancy rate. Further studies are recommended. KEY WORDS: Endometrial thickness, endometrial pattern, pregnancy, ultrasound.