I had IVF so my dating is well known. I am currently 10w1d and have had a very eventful pregnancy so far (ruptured corpus luteum, plateauing HCG, spotting), so have had 5 ultrasounds at the RE. So far, every CRL measurement has been 2-3 days behind known dating--so well within normal limits, and growth exactly on track. I had an ultrasound on Wednesday, 2 days ago, at my RE's office because of some bleeding. (Irritated cervix.) I was 9w6d, CRL measured 9w4d. So completely consistent with all previous scans/growth rate. Heartbeat 180. Embryo moving around a little. Went to the regular OB for the first time today. Two days after my 9w4d measurement. I'm 10w1d. CRL measurement...8w2d. OB was completely unconcerned. She said she has lousy equipment, basically for quick bedside checks, embryo might be curled up, equipment might be off, don't give it another thought. She didn't measure the HB but said it looked good. Embryo was moving around a lot--waving arms and nodding head and wiggling. OB was totally happy. I have my NT scan in 2 weeks. In the meantime, can someone please reassure me that the RE just has better equipment than the OB, and that a moving embryo with a strong heartbeat and nicely forming placenta cannot simply shrink by nine days' worth in 2 days? After growing consistently for 8 weeks? Because at this point I am paranoid.