Prenatal movement abnormality Fetal movements generally become apparent during the second trimester of pregnancy around the 20th week but occasionally up to the 25th week. The initiation of perceptible fetal movements is referred to as 'quickening'. HP:0001557 Abnormal intrauterine movements UMLS:C1849510 An abnormality of fetal movement. HP:0007629 Abnormal fetal physiology