Objective: To evaluate the effects of prostaglandin (PG) E2, given for induction of labor at term, on fetal breathing and body movements.
Methods: Eighteen women with term pregnancies, mild gestational hypertension, intact membranes, and unripe cervices who were not in labor participated in this study. After a 60-minute baseline ultrasound examination of fetal chest and body movements, recorded on videotape, the patients were randomly assigned to either 3 mg intravaginal PGE2 tablets or controls (placebo intravaginal tablets). Following tablet insertion and a 3-hour observation time, a second 60-minute ultrasound recording of fetal movements was taped. The videotape recordings were interpreted according to the total amount of time occupied by fetal body movements and fetal breathing movements.
Results: There was a total of 2180 minutes of ultrasound tape recordings, with 136.2 minutes of fetal body movements (6.2%) and 207.8 minutes of fetal breathing movements (9.5%). Mean (+/- standard deviation) observation times per patient before and after tablet insertion were 60.3 +/- 1.2 and 56.4 +/- 1.2 minutes for the PGE2 group and 60.1 +/- 1.3 and 60.4 +/- 1.1 minutes for the control group. Three hours after PGE2 insertion, there were significant decreases in the percentage of time occupied by body movements (7.8 +/- 3.1 versus 3.4 +/- 2.0%; P < .003) and breathing movements (10.6 +/- 8.6 versus 3.9 +/- 2.3%; P < .007). Three hours after tablet insertion, there were statistically significant decreases in the percentage of time occupied by body movements (P < .025) and breathing movements (P < .01) between the control and study groups.
Conclusion: Induction of labor with intravaginal PGE2 tablets inhibits fetal body and breathing movements. The effects could be due to direct action on the fetus or indirect effects of PGE2 (through uterine contraction and/or endogenous PG).