My daughter is having cramps and some tightening of her tummy she is 5 months pregnant 2nd child is this a concern? she feels like she just did a bunch of sit ups

It : It sounds as though she may be having contractions. These may or may not be concerning. You should call her ob/gyn right away. They will be able to guide you as to whether she should go to the er, go to the ob's office or if the contractions are unconcerning. If she has any bleeding, severe pain or fluid leakage, she should proceed to the er. Good luck!