Hi , i will try best to answer your query, Calcium oxalate are the crystals which are normally seen in urine,they may be increased due to ingestion of certain foods like tomatoes, spinach,cabbage,rhubarb etc... Many epithelial cells may be due to contamination of your urine sample with vaginal secretions and normally RBC and pus cells will be only 0-2/hpf there increase in number shows that you are having a urinary tract infection, which is very common in pregnancy, consult a gynaecologist they will prescribe you a course of antibiotics. your urine results have to come to normal with that , if not so then you might be having a renal or ureteric stones