Feasibility of a randomized controlled trial testing nifedipine vs. placebo for the treatment of preterm labor.
OBJECTIVE
Nifedipine is believed to be a superior tocolytic agent on the basis of efficacy and side-effect profile, but was never prospectively evaluated in a placebo-controlled randomized clinical trial (RCT). In our study, we sought to identify limitations in participation for a would-be RCT comparing nifedipine to placebo.


METHODS
A prospective feasibility study was conducted at Ste-Justine Hospital, a tertiary care center, on women between 24 and 34 weeks' gestation, presenting to the labor and delivery room with obstetrical complaints. Patient information was collected and would-be participants were identified on the basis of pre-established clinical and ultrasound criteria as well as on willingness to participate, as determined by the study research nurse.


RESULTS
During a 6-month period, 483 women presenting with signs and symptoms of preterm labor (PTL) were eligible for further evaluation. A total of 321 (66.5%) women were excluded for obstetrical and medical reasons whereas 125 (25.9%) did not meet strict inclusion criteria (cervical length <25 mm or positive fetal fibronectin). When using strict criteria, only 37 women (7.6%) were found to be eligible for study participation. Subject willingness to participate as assessed by the research nurse was 50%.


CONCLUSIONS
If adhering to strict inclusion/exclusion criteria, the feasibility of an appropriately sampled RCT testing tocolytic therapy against a placebo would require a large concerted multicenter effort to meet sample size demands.
Abenhaim
Haim A
HA
Department of Obstetrics and Gynecology, Université de Montréal, 3175, Côte-Sainte-Catherine, Montreal, Quebec, Canada. haim.abenhaim@post.harvard.edu
Tremblay
Valerie
V
Tremblay
Lise
L
Audibert
Francois
F
D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D015337:Multicenter Studies as Topic / Q000379:methods; D009543:Nifedipine / Q000627:therapeutic use*; D007752:Obstetric Labor, Premature / Q000188:drug therapy*; D010358:Patient Participation; D018579:Patient Selection; D011247:Pregnancy; D011446:Prospective Studies; D011792:Quebec; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D018401:Sample Size; D015145:Tocolysis; D015149:Tocolytic Agents / Q000627:therapeutic use*
D015149:Tocolytic Agents; D009543:Nifedipine