Final answer:
A digital pelvic exam is not performed in cases of placenta previa due to the risk of causing further bleeding.
Step-by-step explanation:
A digital pelvic exam is not performed in the case of placenta previa due to the risk of causing further bleeding. Placenta previa is a condition where the placenta partially or completely covers the cervix. The cervix is very sensitive and can easily bleed when touched, so a digital pelvic exam, which involves inserting fingers into the vagina to examine the cervix, could potentially cause significant bleeding and harm to the mother and baby.