complex, but quite stereotyped movements carried out slowly with a clear sequence of body parts
Head backward, trunk arching, and arms lifting. During pregnancy, they occur infrequently in the human fetes (see figure below).
Fetal stretches
Appearing for the first the first time 10-15 weeks of gestation, they occur infrequently from 10 to 19 weeks (0-9 times per hour), with a slight increase (and then decrease) in the second half of pregnancy. As with hiccups, startles and yawns, these movements persist throughout the life span without changing their pattern. The black line stands for the median and the tray lines for the interquartile range. Figure adapted from Roodenburg, P.J., Wladimiroff, J.W., van Es, A., & Prechtl, H.F.R. (1991). Classification and quantitative aspects of fatal movement during the second half of pregnancy. Early Human Development, 25, 19-35 for 20 to 36 weeks.
See General movements, Hiccups, Infantile responses, Startles