Fundal height fluctuation

Amanda
So for my entire pregnancy my fundal height was measuring exactly where it was "supposed" to. That is until 29 weeks when it measured at 31. My midwife wasn't concerned and said we'd see where I measured next visit. Well I just had my next visit and sadly my midwife was outta town so I had to visit with one of the practices OBs and she said my measurement was at 31. Sadly she was very quick to get away from me so she didn't really leave room for me to ask questions. 
It just occurred to me that my measurement being on schedule means there been no fundal growth in the last two weeks. Is this ok? Did she just have a growth spurt? I had some lower abdominal aches and my belly is further out now so I think my uterus has grown out/my abs finally split. I don't wanna call my midwife if it's normal/ok that the height didn't change since it's now matching my week