Combined elevated midpregnancy tumor necrosis factor alpha and hyperlipidemia in pregnancies resulting in early preterm birth

Objective The objective of the study was to determine whether pregnancies resulting in early preterm birth (PTB) (<30 weeks) were more likely than term pregnancies to have elevated midtrimester serum tumor necrosis factor alpha (TNF-α) levels combined with lipid patterns suggestive of hyperlipidemia. Study Design In 2 nested case-control samples drawn from California and Iowa cohorts, we examined the frequency of elevated midpregnancy serum TNF-α levels (in the fourth quartile [4Q]) and lipid patterns suggestive of hyperlipidemia (eg, total cholesterol, low-density-lipoproteins, or triglycerides in the 4Q, high-density lipoproteins in the first quartile) (considered independently and by co-occurrence) in pregnancies resulting in early PTB compared with those resulting in term birth (n = 108 in California and n = 734 in Iowa). Odds ratios (ORs) and 95% confidence intervals (CIs) estimated in logistic regression models were used for comparisons. Results Early preterm pregnancies were 2-4 times more likely than term pregnancies to have a TNF-α level in the 4Q co-occurring with indicators of hyperlipidemia (37.5% vs 13.9% in the California sample (adjusted OR, 4.0; 95% CI, 1.1-16.3) and 26.3% vs 14.9% in the Iowa sample (adjusted OR, 2.7; 95% CI, 1.1-6.3). No differences between early preterm and term pregnancies were observed when TNF-α or target lipid abnormalities occurred in isolation. Observed differences were not explicable to any maternal or infant characteristics. Conclusion Pregnancies resulting in early PTB were more likely than term pregnancies to have elevated midpregnancy TNF-α levels in combination with lipid patterns suggestive of hyperlipidemia.