It is always better to get it checked out properly, so I would bring this up with your gynae or PD at your next appointment, or even go to the polyclinic sooner if it keeps happening. They can do a urine test to rule out anything like a UTI or protein in the urine, which will give you a clearer picture than us mummies can. Please don't wait too long, just get it looked at so you can have peace of mind, you and baby's health come first.