High-sensitivity C-reactive protein is not independently associated with self-reported infertility in National Health and Nutrition Examination Survey 2015–2018 data

OBJECTIVE: To study the association between high-sensitivity C-reactive protein (hs-CRP) and infertility among reproductive-age women while controlling for obesity and other metabolic markers. Previous studies found a link between infertility and cardiovascular diseases (CVDs). C-reactive protein is a sensitive marker of CVDs, and its levels are affected by obesity. DESIGN/SETTING: We conducted a cross-sectional study using national data from 2015 through 2018. PATIENTS: A total of 940 women aged 20–45 years who self-reported infertility, had hs-CRP values measured, and did not have CRP >10 mg/L, asthma, arthritis, bronchitis, thyroid disease, bilateral oophorectomy, hysterectomy, and who were not breastfeeding or pregnant, premenarchal at the time of study or had menarche after the age of 20. INTERVENTIONS: N/A. MAIN OUTCOME MEASURE(S): Infertility status (ever reporting inability to conceive with 12 months of trying to become pregnant). RESULTS: In comparison to noninfertile women, self-reported infertile women had higher mean of hs-CRP (3.11 mg/L vs. 2.40 mg/L) and higher percentage of moderate/high hs-CRP values (77.0% vs 58.8%). However, after adjusting for metabolic markers, there was a nonsignificant association between moderate/high hs-CRP and self-reported infertility in the multivariable logistic regression analysis. Odds ratio estimates of the association between hs-CRP and infertility increased over 40% after removing obesity measures and/or high-density lipoprotein from regression models. CONCLUSION: There was no association between hs-CRP and self-reported infertility after controlling for obesity measures and other risk factors for CVDs in a sample of U.S. women aged 20–45 years.