Objective
To assess systemic inflammation in relation to fecundability and anovulation. Design: Prospective cohort study among participants in the Effects of Aspirin in Gestation and Reproduction trial who were assigned to the placebo. Setting: Academic medical centers. Patient(s): Healthy eumenorrheic women (n = 572), 18-40 years of age, with one or two pregnancy losses, attempting spontaneous pregnancy. Intervention(s): Baseline serum high-sensitivity C-reactive protein (hsCRP) values <10 mg/L were categorized into tertiles. Main outcome measure(s): Discrete Cox proportional hazards models estimated the fecundability odds ratio (FOR) and 95% confidence interval (CI) and adjusted for potential confounders. Log-binomial regression estimated the risk ratio (RR) and 95% CI of anovulation. The algorithm to define anovulation used data on urinary concentrations of hCG, pregnanediol-3-glucuronide, and LH as well as fertility monitor readings. Result(s): Higher hsCRP was associated with reduced fecundability but not with an increased risk of anovulation.