Baby slow developing...

Jennifer
I did <a href="https://glowing.com/glow-fertility-program">IVF</a>, so my conception dates are pretty spot on.  Today I went in for my 7w ultrasound and the baby is measuring 6w1d with a normal heartbeat for that time frame. My RE said this is okay, but wants another ultrasound in 1 week. Has anyone ever had this happen before? It seems like one thing after another.