Contraindication for dilatation and curettage:
Ref. The Short Textbook of Pediatrics. Pg 650
 
Dilation and Curettage
Indications

Retained placenta after vaginal delivery (postpartum)
Retained products of conception after missed, incomplete, or inevitable abortion/miscarriage
Elective first-trimester abortion
Molar pregnancy
Evaluation of abnormal uterine bleeding

Contraindication

Untreated acute pelvic infection (endometritis, salpingitis, pyometra)
Coagulopathy
Possible fetal viability (except for elective termination)
Patient refusal
TB Endometrium
Acute PID
Post-menopausal bleeding
Carcinoma endometrium