Effect of ritodrine hydrochloride infusion on fetal movement with the use of a fetal movement acceleration measurement recorder (FMAM recorder).

Aim: To investigate the effect of ritodrine hydrochloride infusion on fetal movement.

Method: We gathered 20 pregnant women who received ritodrine hydrochloride infusion as the treated group, and 147 pregnant women who did not as the control group. All women recorded gross fetal movement with the fetal movement acceleration measurement recorder after 28 gestational weeks. The record was divided into epochs of 10 s, and the ratio of movement-positive epochs to all epochs was calculated as the fetal movement index. Furthermore, the mean duration and the mean number per hour of no-fetal movement period, where the fetus did not move for 5 min or more, were calculated as the indexes of no-fetal movement. All indexes were compared between the two groups at 28-31 and 32-35 gestational weeks.

Results: The fetal movement indexes (%) were 17.29 ± 7.46 (mean ± SD) in the control group and 13.65 ± 7.13 in the treated group at 28-31 weeks (p = 0.139). At 32-35 weeks, they were 14.55 ± 6.43 and 18.50 ± 5.33, respectively (p = 0.03). Similarly, the no-fetal movement indexes (min, times/h) were 15.03 ± 10.99 and 1.61 ± 0.88, and 18.70 ± 15.80 and 1.75 ± 0.96 (p = 0.824, and 0.673) at 28-31 weeks. At 32-35 weeks, they were 18.13 ± 10.88 and 1.95 ± 0.97, and 9.20 ± 5.51 and 1.14 ± 0.71, respectively (p = 0.003, and 0.003).

Conclusion: Ritodrine hydrochloride infusion increased the fetal movement and decreased the no-fetal movement period at 32-35 weeks.