BACKGROUND: Preterm prelabour rupture of membranes (PPROM) is a common preterm 
birth antecedent. Preterm infants experience increased adverse newborn outcome 
risks. Infection is a risk factor for early birth in PPROM. Current management 
is antibiotic therapy, antenatal corticosteroids and to plan delivery at 
37 weeks gestation. The microbiota and probiotics are potentially protective and 
may improve outcomes.
AIMS: The primary aim is to evaluate whether oral probiotic therapy 
(Lactobacillus fermentum CECT5716) administered during PPROM between 24 and 
34 weeks gestation prolongs pregnancy duration. The secondary aim is to evaluate 
maternal and neonatal outcomes.
MATERIALS AND METHODS: This is a pragmatic, multicentre, double-blind, 
placebo-controlled randomised controlled trial in Australia. The population will 
be women with a singleton pregnancy and PPROM less than 34 weeks gestation. The 
intervention will be an oral probiotic therapy compared with a placebo control. 
The primary outcome will be the proportion of women still pregnant at seven days 
following PPROM. One-to-one randomisation will occur within 24 h of PPROM. The 
trial is powered (80%, alpha = 0.05) to detect an absolute percentage increase 
in the primary outcome of 30%, (from expected rate of 20% up to 50%).
DISCUSSION: This trial will provide evidence for the effectiveness of the 
probiotic in prolonging pregnancy duration. Findings will inform the feasibility 
of a larger trial to examine the effect of oral probiotics on clinically 
important maternal and neonatal outcomes in PPROM.