High-sensitivity C-reactive protein levels and pregnancy outcomes in women with unexplained infertility after ovarian stimulation with intrauterine insemination in a multicenter trial

OBJECTIVE: To determine if chronic inflammation, assessed by basal high-sensitivity C-reactive protein (hs-CRP) levels, is associated with pregnancy outcomes in women with unexplained infertility undergoing ovarian stimulation with intrauterine insemination. DESIGN: Prospective cohort analysis of the Reproductive Medicine Network’s Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) randomized controlled trial. SETTING: Multicenter university-based randomized controlled trial. PATIENT(S): A total of 781 couples with unexplained infertility. INTERVENTION(S): Secondary analysis. MAIN OUTCOME MEASURE(S): Adjusted risk ratios of live birth, clinical pregnancy, and pregnancy loss rates by hs-CRP levels. RESULT(S): Associations between hs-CRP levels and clinical pregnancy rates were not observed after adjustment for baseline body mass index. There were fewer live births among women with higher hs-CRP levels, although confidence intervals crossed 1.0. The risk of pregnancy loss was greater in women with increased hs-CRP levels (1–3 mg/L: risk ratio [RR], 1.67; 95% confidence interval [CI], 1.00–2.79; >3–10 mg/L: RR, 1.84; 95% CI, 1.06–3.20; and >10 mg/L: RR, 2.14; 95% CI, 1.05–4.36 compared to women with hs-CRP <1 mg/L). CONCLUSION(S): This investigation suggests that chronic inflammation may increase the risk of pregnancy loss but not impact the clinical pregnancy rate in women with unexplained infertility undergoing ovarian stimulation with intrauterine insemination. Associations between inflammation and pregnancy outcomes in women with infertility merit further investigation. CLINICAL TRIAL REGISTRATION NUMBER: clinicaltrials.gov NCT01044862.