Temporal organization of fetal behavior from 24-weeks gestation onwards innormal and complicated pregnancies

Developmental aspects of behavioral organization were investigated in 29 he althy fetuses from 24-weeks gestation onwards: (a) short-term association b etween body (GM) and eye (EM) movements; (b) linkage of pairs of the three state variables [fetal heart rate pattern (FHRP), GM, and EM]; and (c) sequ ence of change of state variables during transitions. Linkage and sequence were also studied in complicated pregnancies. Short-term association between GM and EM was well established after 28 week s. Linkage of state variables improved considerably after 32-34 weeks. FHRP was the first variable to change during synchronized transitions from 1F t o 2F between 28-39 weeks, and the last variable during 2F to 1F transitions between 32-39 weeks. Although clear developmental patterns could be recognized, the interfetal v ariability was such that identification of the abnormal fetus is still diff icult. Only transitions were significantly different in growth-restricted f etuses, as they showed no specific sequence of change. Assessing the tempor al organization of fetal behavior seems, therefore, until now, not of great clinical value. (C) 1999 John Wiley & Sons, Inc.