Background: Placental dysfunction, inflammation and degradation of fetal 
membranes has been hypothesized as a cause of preterm prelabor of rupture of 
membranes.Objective: To examine the effect of aspirin, an anti-inflammatory 
agent, on the prevalence of preterm prelabor rupture of membranes 
(PPRoMs).Methods: A retrospective analysis was conducted to examine the effect 
of aspirin on the prevalence of PPRoM. Aspirin (150 mg, nocte) was prescribed to 
women who were identified through a screening program at 11-13+6 weeks' 
gestation as being at high risk for developing early-onset preeclampsia. Women 
who were at low risk for developing preeclampsia did not receive aspirin. The 
prevalence of PPRoM was compared with an observational cohort.Results: In the 
observational cohort, there were 3027 women, including 32 (1.1%) cases of PPRoM. 
The prevalence of PPRoM in the high risk group was 3.1% (4/128) and was 
statistically significantly higher compared to the low risk group (1.0%) 
(28/2899). The relative risk was 3.02 (95% CI 1.2-7.7; p= .04). In the 
interventional cohort, there were 7280 women, with 114 (1.6%) cases of PPRoM. 
The prevalence of PPRoM in the high risk group who were treated with aspirin was 
1.8% (14/766) compared to 1.5% (100/6516) in the low risk group (p= .54). The 
prevalence of PPRoM in high risk patients in the observational group (who did 
not receive aspirin) compared with the high risk patients in the interventional 
group (who were treated with aspirin) was not statistically significant 
(p= .31).Conclusions: PPRoM is significantly associated with a description of 
high risk for ePET; although, this algorithm is not a good screening tool for 
predicting PPRoM. Aspirin treatment of women deemed high risk for ePET is safe 
in the context of PPRoM and there may be some reduction in prevalence of PPRoM 
in treated high risk women; although, this study was not powered to demonstrate 
a small reduction in the prevalence of PPRoM. The findings merit further 
investigation through a larger prospective study with adequate sample size.