Behavioral States Duration (sec) Occupancy %I Fequency (cpm) A/B ratio (%) N Resting 0 0 0 0/0 12 Active 29.7 ± 10.3 32.7 ± 14.8 0.7 ± 0.2 1.4 ± 0.4 14 Intermediate 17.7 ± 3.7 6.4 ± 1.8 0.2 ± 0.03 1.2 ± 0.3 5 Highly active 88.6 ± 14.6 44.1 ± 5.3 0.5 ± 0.3 1.2 ± 0.1 3

Table 2: Quantitative values in four fetal behavioral states detected by fetal ACGs. The behavioral state of a fetus will be determined by comparing the ACG data to this table. The A/B value was constant among three behavioral states of normal fetus, i.e. the A/B ratio will be feasible to evaluate the fetal well-being.