Cerebellum measurement?

Today while going over my anatomy scan my OB said the cerebellum was measuring in the less then 5th percentile. She said the tech also noted it was hard to get a scan of that area so we are rescheduling another scan in 8 weeks. She didn’t say much about it but then asked me if I had done genetic testing (we didn’t) ....now I have to wait 8 weeks to find out if something is wrong or if it was just a bad measurement! Anyone else experienced this? I’m not find much in what a small cerebellum could indicate...all other measurements were fine.