Thickened lining, Endometrial biopsy was benign but scant tissue sample. Dr says repeat biopsy in 30 days or do D & C & hysterscopy. How do I decide?

Discuss with doctor. This decision will need to be made by you and your doctor together. The sonogram should be reviewed to determine the thickness and appearance of the endometrial lining. If there are concerns that adequate sampling was not obtained by biopsy then direct visualization by Hysteroscopy may be warranted.