AbstractObjectiveTo evaluate if, and to what extent, Pipelle de Cornier® endometrial sampling influences the ultrasonographic features of the endometrium.MethodsThis was a prospective descriptive study on 99 consecutive women in whom a Pipelle endometrial biopsy was performed. All patients first underwent a transvaginal ultrasound evaluation of the uterus. The endometrial thickness (ET) was measured and endometrial sonographic features were recorded. Thereafter, a Pipelle endometrial biopsy was taken. Finally, the ultrasound examination was repeated. The patients' characteristics, the sampling procedure, the endometrial histology and the sonographic findings before and after Pipelle biopsy were compared.ResultsNinety‐nine women, of whom 45% were postmenopausal, entered the study. The mean age was 59.0 years (SD, 9.9) for the postmenopausal women, and 41.6 years (SD, 8.7) for the rest. On histological examination, endometrial cancer was diagnosed in four patients and endometrial hyperplasia in eight patients. The average ET before Pipelle sampling was 9.0 mm (SD, 6.6) vs. 8.6 mm (SD, 7.0) after biopsy (P < 0.0001). After Pipelle sampling, the endometrium was less clearly delineated (P = 0.03) and more echogenic endometrial spots were seen (P < 0.0001). If an endometrial three‐layer pattern was noted before sampling, it was not observed in most women after Pipelle biopsy (P = 0.0003).ConclusionsET measurements are affected by Pipelle sampling and the quality of the ultrasound features tends to be altered by biopsy. Performing the ultrasound examination before proceeding with endometrial sampling may therefore improve diagnostic accuracy of ultrasound. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.