What Causes Reddish Vaginal Bleeding During IVF Procedure?

I m safi and my ivf procedure done last 18 march after 2 or 3 days I saw lite reddishnes bleed sometimes than for doctor recommend I take trenexa mf tablet is this safe or normal and one thing more I had a conticipation today morning I go to the bathroom and after freshen up after that I had some stomache is it fine for my ivf procedure I m so worried about this