Talk to Gynecologist on Light Menstural Flow

I had two miscarriages in last two years. I had last miscarriage six months back in 8th week of pregnancy. I used abortion pills to remove the tissues. My ultrasound report was also clear Bt after that my periods are regular Bt every month the flow is very light just like spotting for 5 to 6 days. Than it stops. Kindly suggest shud I go for ultrasound again or some hormones test or its normal? Doctor suggested me to take multivitamin iron tablets for 6 months after the miscarriage Bt I didn't continued it more than a month. So this bleeding could b bcz of some nutritional deficiency?