A prospective randomized trial of acute tocolysis in term labour with atosiban or ritodrine.
OBJECTIVE
To study the effects of the tocolytics atosiban and ritodrine in term labour.


METHODS
Women in term labour, requiring acute tocolysis, were prospectively randomized for treatment with either atosiban i.v. (n=70) or ritodrine i.v. (n=70). There were three indications for acute tocolysis: (1) fetal distress followed by continuation of labour, (2) fetal distress followed by emergency caesarean section (CS), and (3) arrest of contractions in women waiting for a secondary CS in the absence of fetal distress. Primary endpoints were maternal blood pressure (MBP) and maternal heart rate (MHR). Secondary endpoints were intra-uterine pressure, fetal heart rate (FHR), 5'-Apgar score and umbilical arterial pH.


RESULTS
Baseline characteristics did not differ between the study groups. The ritodrine group showed a significant rise in MHR (p<0.001), MHR remained unaltered in the atosiban group (p=0.31). No significant changes occurred in systolic and diastolic BP in either group. FHR rose by a maximum of 11.6 bpm (8.5%) in the ritodrine group (p<0.001) compared to a rise of 4.9 bpm (4.8%) in the atosiban group (p=0.27). No differences were found in blood loss and fetal outcome. Compared to baseline, uterine pressure was reduced by a maximum of 55% (p<0.001) after ritodrine administration, compared to a maximal reduction of 54% (p<0.001) after atosiban administration. These effects did not differ between the two treatment groups.


CONCLUSIONS
Considering the maternal effects, our results suggest a possible role for atosiban bolus in acute tocolysis in term labour.
de Heus
Roel
R
Department of Perinatology & Gynecology, University Medical Centre Utrecht, The Netherlands. roeldeheus@hotmail.com
Mulder
Eduard J H
EJ
Derks
Jan B
JB
Kurver
Piet H J
PH
van Wolfswinkel
Leo
L
Visser
Gerard H A
GH
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007743:Labor, Obstetric / Q000187:drug effects*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012312:Ritodrine / Q000494:pharmacology* / Q000627:therapeutic use; D047929:Term Birth / Q000187:drug effects*; D015149:Tocolytic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D014668:Vasotocin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
D015149:Tocolytic Agents; C047046:atosiban; D012312:Ritodrine; D014668:Vasotocin