Little is known about the manner in which motor behavior of the gross motor movements develops in early fetal period. Therefore, the goal of this study was to identify and classify the fetal distinct behavior patterns of the gross motor movements qualitatively in gestational weeks 10 through 17 (N = 69 fetuses). Using our unique Systematic Observation and Analysis Procedure based on conventional 2D ultrasound, we were able to identify the distinct behavior patterns with respect to the fetus' orientation (e.g., postural position and additional support by uterine wall) in real time and therefore distinguish 12 categories of behavioral patterns. The kappa coefficient for this procedure was 0.82, indicating high interobserver reliability. Interestingly, six of these 12 categories were not observed in gestational week 10–11, whereas all 12 movement categories were present in gestational week 16–17. Importantly, the occurrence of early development of gross motor control in utero emerges in the presence of dynamic and interactive environmental factors, providing new insights into the fundamental aspects of developmental motor behavior in the growing infant. Highlights We developed a system for real‐time monitoring of behavioral patterns of the gross motor movements with respect to the fetus' intrauterine orientation using a two‐step, non‐invasive observation protocol. Our monitoring system allowed us to detect twelve separate categories of distinct behavioral patterns of the gross motor movements in gestational week 10–17. Gross motor control develops in the early fetal period and is affected by the presence of dynamic and interactive environmental factors.