(373) Allostatic Load Score is Associated with Gestational Age at Delivery in a Dose Dependent Manner

Allostatic load (AL) is a multidimensional construct that encompasses cumulative stressors, and is associated with a multitude of adverse health outcomes outside of pregnancy. Despite this, there is no ‘standard’ definition of AL, and the relationship between AL and preterm birth (PTB) remains poorly defined.


Study Design:

Secondary analysis of a prospective cohort enriched for those at high a priori risk of PTB. Participants identifying as Black, White, and/or Hispanic, with singleton, non-anomalous gestations were recruited < 22 weeks, 2017-2022. At enrollment, baseline health data and blood samples collected. We considered 6 markers previously considered in other AL indices: CV domain factors (initial prenatal systolic BP, initial prenatal diastolic BP), a metabolic factor (pre-pregnancy BMI), and inflammation (plasma IL-6, IL-10, and IL-1β levels). Each marker was classified as ‘high’ (≥75^th centile; 1 point) or ‘low’ (< 75^th centile; 0 points). The total AL score was calculated by summing these 6 factors for a max AL score = 6. The primary outcome was GA at delivery (continuous). Secondary outcomes were PTB < 37, < 35, and < 28 wks.  Data were analyzed by t-test, chi-square, Cox regression, and Kaplan-Meier survival.

 


Results:

493 participants were included, delivering at a median 38.3 (IQR 36.9, 39.3) weeks’. The median AL was 1 (IQR 0, 2). Clinical characteristics are shown in Table 1. In Cox regression models, an AL score of 0 was associated with pregnancy prolongation [adjusted Hazard Ratio (aHR) 0.81, 95% CI 0.67, 0.99]; in contrast, AL scores ≥1 were associated with an increased aHR of delivery in a dose dependent manner (Figure 1A). In survival analyses, those with a high AL scores [≥75^th centile (≥2)] delivered earlier (Figure 1B, log-rank p=0.0014).


Conclusion:

A multidimensional AL score calculated early pregnancy is associated with delivery gestational age in a dose-dependent manner. Several of these AL components are potentially modifiable; future studies should evaluate whether optimization of health / improvement in these metrics is associated with improved perinatal outcomes.