My Niece Is Having Her First Baby...she Has Had All

My niece is having her first baby...she has had all her blood work,ultra sounds and they all came back normal.
The Doctor mentioned that she has a little longer uterus then usual ...she is in her 6th month..The Doctor said not to worry ...the uterus is long....not wide. I just want to know how the longer Uterus would be any different then a normal one. I do know a smaller uterus you must be careful!