Associations between BMI and infertility.

<div><p>Background</p><p>One of the risk indicators of infertility is obesity. The cardiometabolic index (CMI) comprises obesity and blood lipids and is regarded as a novel indicator for evaluating obesity. Nevertheless, it is unclear whether it has any connection to infertility. This study set out to investigate the association between infertility and CMI.</p><p>Methods</p><p>Based on cross-sectional data from the 2013–2018 National Health and Nutrition Examination Survey (NHANES), infertility and CMI statistics with complete information were selected. This study investigated the correlation between CMI and infertility using multivariate logistic regression analyses and subgroups. Use fitted smooth curves and threshold effect analysis to describe the nonlinear association between CMI and infertility.</p><p>Results</p><p>202 (13.31%) among the 1720 participants that got involved in the investigation were female infertile. Among the three models, the outcomes confirmed a positive correlation between CMI levels and the incidence of infertility (OR = 1.12, 95% CI: 1.01–1.24). Additionally, significant relationships were maintained in subgroup analysis (p > 0.05). Smooth curve fitting indicated a nonlinear positive connection between CMI and infertility, and an inflection point of 0.93 (log-likelihood ratio <i>P</i> < 0.05) was shown by threshold effect analysis.</p><p>Conclusion</p><p>Our findings suggest a significant relationship between CMI and infertility in American females. This helps identify high-risk groups for infertility, informing clinical practice and public health policy to improve metabolic and reproductive health.</p></div>