Can i use a feminine intimate wash with ph- balanced after frozen embryo transfer?

Don't do it. Despite all the available commercial vaginal douche ("intimate wash") products, douching is very unhealthy. It's unnecessary for vaginal hygiene, removes natural healthy bacteria, and prootes their replacement with unhealthy ones, often resulting in bacterial vaginosis, increased risk of STDs if exposed, and sometimes contributes to pelvic inflammatory disease. Never douche!