Lonopin injection. Require to take this?

After a couple of rounds of unsuccessful iui, our doctor suggested we go a little aggressive this cycle. I already had underwent a hysteroscopy and polypectomy in September n everything else looked normal. One concern that surfaced was my endometrium thickness which hardly reached 7/7.5 by ovulation. This cycle I was taking progynova and 6 Newmon R 150 injection. My doctor then asked me to get a endometrium doppler done on day 9. Blood flow was just reaching zone 2, nothing in zone 3&4. She advised me to take lonopin injection 40 mg everyday. After two days I was to re do an endometrium Doppler and blood flow improved to zone 4. Then I had my iui and am taking Duphaston, progynova n the lonopin injection. My question how does the lonopin injection helps in implantation and how long would I require to take this? I have no history of miscarriage.