Your supposed to be measured every few weeks from 26 weeks onwards. My best friend wasnt and it wasnt until she went to c a specialist doctor about coming off anixety tablets, and by chance that he measured her bump "just out of curiosity" that they found out her baby was small for size and had to be put on growth watch, she was delivered 4 weeks later at 34 weeks weighing 3lb because she wasnt growing properly. She was told that if it had gone un-noticed her baby would have been a stillborn.
Please push to have your selves measured.