Human fetal and neonatal movement patterns: Gender differences and fetal-to-neonatal continuity

Longitudinal quantification of leg movements per minute for human subjects during both fetal and neonatal periods was accomplished from videotapings c onducted antenatally (ultrasonography 30, 34. and 37 weeks gestational age) and postnatally (birth and 6 weeks of age). Fetal/neonatal subjects displa yed decreasing numbers of leg movements per minute during antenatal develop ment (30 to 37 weeks), followed by increasing numbers of leg movements per minute during postnatal development (birth To 6 weeks of age). Male subject s displayed greater numbers of leg movements per minute than female subject s during both antenatal and postnatal development. Fetal-to-neonatal contin uity for numbers of leg movements per minute was found for comparisons betw een fetal (37 weeks gestational age) and neonatal (during sleep stares at b irth) measures, and females displayed a stronger and different movement con tinuity pattern than males. These results indicate a differential time cour se for neurobehavioral development of male and female fetuses/neonates, and the findings have implications for the clinical assessment of fetal neurob ehavioral development and well-being. (C) 2001 John Wiley & Sons, Inc.