contraction is tightening of the uterus and then relax. kaya paninigas ng tiyan ang mararamdaman. this helps to push the baby out. kaya its not good if you have a finding na may contraction at 16weks. i experienced cramping, parang magkakaroon. akala ko, ok lang. pero i informed my OB. pina TVS niako. nakita na may contraction. as per OB, threatened abortion daw un. kaya pinag bedrest at pampakapit ako for 2weeks.