Allostatic load in women with infertility: a cross-sectional analysis study from NHANES 2015-2018

Infertility affects approximately 15% of couples globally and is recognized as a major public health concern. Infertile women often experience significant psychological stress due to various factors, including work-related pressures, family dynamics, and reproductive challenges. However, the role of allostatic load-a marker of chronic stress and physiological dysregulation-in infertile women has been scarcely investigated.

This study aimed to explore the association between allostatic load and infertility, as well as to identify potential biomarkers that can predict allostatic load in infertile women.

The study included 419 participants from the 2015-2018 National Health and Nutrition Examination Survey (NHANES), comprising 59 individuals with infertility and 360 controls. Allostatic load was assessed using a composite of biomarkers, including diastolic blood pressure (DBP), systolic blood pressure (SBP), body mass index (BMI), abdomen circumference (AC), homeostatic model assessment of insulin resistance (HOMA-IR), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and high-sensitivity C-reactive protein (hs-CRP). Data analysis was performed using R (R Core Team, 2021) and IBM SPSS Statistics 22.0, with statistical significance set at P < 0.05.

Women with infertility had significantly higher AC, BMI, and SBP, but lower HDL levels compared with controls (all p < 0.05), after weighting, the differences between the two groups in AC, BMI, and HDL remained statistically significant (P = 0.021, 0.035, 0.024. respectively). The allostatic load score was also significantly higher in the infertility group (p = 0.011), after weighting, this difference remained statistically significant (P = 0.029). Subgroup analysis suggested a stronger association between allostatic load and infertility among non-smoking women. BMI, LDL, TG, HDL, and hs-CRP were identified as key biomarkers predictive of allostatic load in infertile women.

Allostatic load was significantly higher in infertile women, highlighting the importance of assessing allostatic load in clinical management, particularly among non-smoking women. BMI, LDL, TG, HDL, and hs-CRP were identified as key biomarkers associated with allostatic load in this population.