Hiya, and sorry for your loss
Im no expert but the only thing i can think of is this..
Sometimes your hormone levels are monitored after a mc to see whether your hcg levels are dropping or have left your system as if they dont it can indicate you still have retained tissue which will have to come out due to a risk of infection.
Unless, your doctor indicates to you that he thinks there was a hormonal imbalance that caused your mc (like low progesterone) i think its more likely that he's checking for the hcg. cd 35 is not rare at all with no af so i suppose, in my humle opinion, he's just being proactive with you.
If you're really worried speak to him, that what he's there for.
Good luck, hun..sorry i have no better info..

, Omi xxx