Monitoring the progressive increase of the longest episode of spontaneous movements in Guinea pig fetus

The aim of this work was to determine the changes in the duration of spontaneous movements in the guinea pig fetus after the appearance of its first movements. Every day from the 25th to the 35th gestation day, one fetus from each of twenty pregnant animals was examined by ultrasound. Fetal movements were observed for 5 min. The episode with the longest period of movement was taken into consideration and was recorded as: <1 s, 1-3 s, and >3 s. Days 25 and 26 were characterized by episodes lasting <1 s; days 29 to 31 were dominated by episodes lasting 1-3 s, and days 34 and 35 by episodes lasting >3 s (?2 = 140.51 p <0.05). Tracking the dynamics of progressive increases in the longest episode of spontaneous movement could be a useful factor in estimating the maturity and condition of a fetus.