Introduction:
To explore the association between childbirth experience and multiple health outcomes, and to discuss the role of blood lipids.

Material and methods:
The cross-sectional study utilized data from NHANES from 2007 to 2020. Blood lipid indexes were included triglyceride,TC, LDL-C and HDL-C. Then, RC was calculated.

Results:
A total of 3889 participants were included in this study. The incidence of most diseases among women who had childbirth were significantly increased (p<0.05), especially high blood pressure (40.77% vs 19.57%, p<0.001), diabetes (13.15% vs 5.86%, p<0.001), heart disease (7.75% vs 1.69%, p<0.001) and arthritis (35.22% vs 17.57%, p<0.001). The individuals with two diseases were the most common (29.1%), and overweight-high blood pressure-arthritis was the most important comorbidity mode. After additionally adjusting, the risks of seven kinds of medical conditions (heart disease, cancer, kidney stones, arthritis, thyroid problem, diabetes and high blood pressure) in the women who had given birth were significantly increased. The odds ratios (OR) were 1.57~3.54 and 95% confidence intervals (CIs) were 1.15~6.97 (p<0.0001), and birth number would increase the risks. In addition, the level of RC was significantly increased in the women who developed the seven kinds of medical conditions (p<0.001). A nonlinear (L-shaped) relationship of blood RC was observed in heart disease, arthritis, cancer, diabetes and high blood pressure, and mediation analysis demonstrated that blood RC accounted for 8.2%, 10.6%, 6.84%, 17.7%, 12.5% of observed association.

Conclusions:
Childbirth history leaves an indelible imprint on women’s multiple health outcomes, with RC serving as both a biomarker and mediator of long-term disease risk.