The ontogeny of limbs movements towards midline in healthy infants born at term

Movements towards midline are part of the age-adequate motor repertoire of infants. They develop contemporaneously to general movements, changing from occasional simple contact to proper midline motor patterns. The aim of this study is to describe the ontogeny of movements towards midline in full term healthy infants. Parents were asked to record their infant every second week, from term age to 22 weeks post-term. 25 healthy full-term infants. Three main epochs of development were detected: in the first one, between birth and 4 weeks post-term, movements towards midline were occasional, apparently due to the dominant flexed posture of elbow and knees and the adducted posture of shoulders and hips. In the second epoch, from 4 to 8 weeks, the limbs movements towards midline markedly decreased. In the third one, after 8 weeks, movements towards midline increased again in frequency, first appearing in lower limbs then in upper limbs, first solely as contact and thereafter as manipulation. A temporal overlapping with the occurrence of intermittent or continual fidgety movements was detected. Movements towards midline progressively change, through a defined timeline, in full term healthy infants. The increased knowledge about the normal age-adequate motor repertoire can help physicians in clinical assessment of high risk infants. •Movements towards midline change during time from occasional simple contacts to more advanced midline motor patterns.•Movements towards midline increase in frequency first in lower limbs and then in upper limbs.•Movements towards midline develop contemporary to fidgety movements.