Hi Doctor. I Had A Missed Miscarriage Detected In 8th

Hi doctor. I had a missed miscarriage detected in 8th gestational week. Got Dn E done then and was detected with chronic cervicitis during the procedure. In my follow up check up doctor has prescribed inj. Placentrex for 14 days. Is the injection safe and is it absolutely required. Meanwhile doctor has told me to not to try to conceive for the next six months as I will be starting Gardasil vaccine. Please advice.