Interesting, I'm not sure I'd ever really heard or paid attention to this.
DS was born at just past 37 weeks after preterm labor starting at 30 weeks - including 18 days in the hospital (32.5-35 weeks). He had a traumatic birth and had head trauma as well. He is definitely gifted but may have some other stuff going on - we've always said he had the preemie problems but wasn't the preemie.
DD was born at 29 weeks after preterm labor starting at 23 weeks - including 18 days in the hospital (26.5-29 weeks). She had an easy delivery and then spent 45 days in the NICU having many many feeding and intestinal issues. While physically delayed early on she has since fully caught up and while we haven't had her tested I would say she is most likely gifted - just differently then her brother. She is also on the taller/larger side compared to many of the other kids her age (or even a bit older).