Red blood cell long-chain polyunsaturated fatty acid (LC-PUFA) levels in pregnant women predict length of gestation via effects on sleep quality and inflammation

Abstract

Objective Mechanistic pathways linking maternal long-chain polyunsaturated fatty acid (LC-PUFA) status with gestational length are poorly delineated. Key LC-PUFAs implicated in this association are the antiinflammatory omega-3 docosahexaenoic acid (DHA) and proinflammatory omega-6 arachidonic acid (AA). We hypothesized that (1) lower red blood cell (RBC) DHA:AA ratios would predict shorter gestation and (2) this effect would be mediated by both inflammation and sleep quality. Methods Pregnant women (n = 135) provided blood and completed the Pittsburg Sleep Quality Index at 20–27 weeks gestation. RBC fatty acids were determined by gas chromatography and serum inflammatory markers (IL-6, IL-8, TNF- α , IL-1 β , CRP) were determined by high-sensitivity ELISA. Results Lower DHA:AA ratios predicted higher serum IL-8 (r = −0.20, p = 0.02) and poorer sleep quality (b = −13.8, p = 0.02). These relationships remained after adjusting for depressive symptoms, age, BMI, income, race, and smoking. Mediational analyses demonstrated indirect effects linking lower RBC DHA:AA with shorter gestation via higher IL-8 (95% CI = 0.10, 3.84) and poor sleep (95% CI = 0.35, 3.99). A significant race X DHA:AA interaction in predicting preterm birth (PTB) was observed (p = 0.049); among African Americans only, the odds of PTB decreased significantly as DHA:AA increased (OR for 0.1 unit increase = 0.25 (95% CI = 0.06, 0.99, p = 0.048). Discussion These data support both inflammatory pathways and sleep quality as significant mediators linking maternal DHA:AA status and length of gestation. African Americans may be at greater risk for PTB related to suboptimal DHA levels.