The Randomized Nitric Oxide Tocolysis Trial (RNOTT) for the treatment of preterm labor.
OBJECTIVE
This study was undertaken to assess the effectiveness of glyceryl trinitrate (GTN) patches in comparison with beta2 sympathomimetics (beta2) for the treatment of preterm labor.


METHODS
A multicenter, multinational, randomized controlled trial was conducted in tertiary referral teaching hospitals. Women in threatened preterm labor with positive fetal fibronectin or ruptured membranes between 24 and 35 weeks' gestation were recruited and randomly assigned to either beta2 or GTN with rescue beta2 tocolysis if moderate-to-strong contractions persisted at 2 hours. Obstetric and neonatal outcomes were assessed.


RESULTS
Two hundred thirty-eight women were recruited and randomly assigned, 117 to beta2 and 121 to GTN. On a strict intention-to-treat basis, there was no significant difference in the time to delivery using Kaplan-Meier curves (P = .451). At 2 hours, 27% of women receiving beta2 had moderate or stronger contractions compared with 53% in the GTN group (P < .001). This led to 35% of women in the GTN group receiving rescue treatment. If delivery or requirement for beta2 rescue are regarded as treatment failure, then a significant difference was observed between the 2 arms (P = .0032). There were no significant differences in neonatal outcomes.


CONCLUSIONS
GTN is a less efficacious tocolytic compared with ss2 sympathomimetics.
The Mothers and Babies Research Centre, Faculty of Medicine and Health Sciences, The University of Newcastle, Australia.
A
A
Bisits
G
G
Madsen
M
M
Knox
A
A
Gill
R
R
Smith
G
G
Yeo
K
K
Kwek
M
M
Daniel
T N
TN
Leung
K
K
Cheung
T
T
Chung
I
I
Jones
J
J
Toohill
D
D
Tudehope
W
W
Giles
D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D000328:Adult; D036861:Delivery, Obstetric; D005260:Female; D005865:Gestational Age; D006801:Humans; D005996:Nitroglycerin / Q000009:adverse effects / Q000627:therapeutic use*; D007752:Obstetric Labor, Premature / Q000188:drug therapy*; D011247:Pregnancy; D011256:Pregnancy Outcome; D013997:Time Factors; D015149:Tocolytic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome
D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists; D015149:Tocolytic Agents; D005996:Nitroglycerin