Among 609 pregnant females observed at our three visits, the means in relative frequencies (%) of lying, standing, sitting, vacuum chewing, drinker playing, and bar biting for 6 h were 60.1 ± 0.91, 32.3 ± 0.87, 7.60 ± 0.44, 12.7 ± 0.65, 0.4 ± 0.06, and 0.2 ± 0.50%, respectively