Baby measuring big?

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I went to my ultrasound today (I'm 16w6d) and everything looks great, but they told us the baby is measuring about 8 ounces! According to this app and everything else I read, babies should be about 5 ounces around now. He's always measured a few days ahead because I have a short cycle, but some of his parts were measuring a full week and a half ahead! Doctor and tech reassured us all of this is normal and that babies fluctuate a lot at this stage, but just wondering if anyone here has had this experience and, of so, did your baby stay big, or did things even out?