Hello everyone) I have a question. My last period was on June 26th…

Hello everyone) I have a question. My last period was on June 26th, according to my gynecologist's diagnosis. According to the ultrasound, I had it on June 23rd. The question is: who gave birth according to the ultrasound or by the gynecologist's deadline? It's interesting. My first childbirth happened according to the ultrasound, coinciding with the date. So, the gynecologist diagnosed me on April 2nd, but I gave birth on March 28th. Not more than a month difference. What's going on now? ?