Concered dating scan

mamabear

So long story short I had two ultrasounds 12 hours apart the first showed a baby measuring 6weeks 4 days with HR of 113 (should have been 6weeks 5 days)the next morning I had another and baby measure only 6 weeks 3 days with HR of 113. (Should have been 6 weeks 6days) Is baby shrinking and not doing well why did it not progress? I know it was short time between the two but now I’m left confused and worried any input?