Advanced lipoprotein measures and recurrent preterm birth.

Objective: Lipoproteins are associated with atherogenic and inflammatory processes, and these processes may be related to adverse pregnancy outcomes. We therefore examined whether variations in lipoprotein particle size and concentration are associated with preterm birth (PTB) <35 weeks' gestation.

Study Design: This is a case-control ancillary study to a randomized trial of omega-3 fatty acid supplementation to prevent recurrent PTB. We measured standard lipids and used nuclear magnetic resonance (NMR) spectroscopy to characterize 17 lipoprotein particles from plasma collected at the baseline randomization visit (16-21 weeks' gestation) in 128 cases (PTB <35 weeks' gestation) and 132 term controls. Logistic regression models controlled for study center, race/ethnicity, number of prior PTB, smoking, and treatment group, as well as total low-density lipoprotein (LDL), high-density lipoprotein, and triglyceride concentrations when examining LDLNMR, high-density lipoproteinNMR, and very LDL (VLDL)NMR, respectively.

Results: Only 1 of the 17 NMR lipoproteins was associated with recurrent PTB. We observed an increased odds of recurrent PTB of 1.04 (95% confidence interval, 1.01-1.08; P = .02) per nanometer increase in VLDLNMR particle size and an odds ratio of 3.00 (confidence interval, 1.40-6.43; P = .005) for the third tertile of VLDLNMR particle size compared with the first tertile.

Conclusion: In women with prior PTB, variations in midpregnancy lipoproteins were not associated with recurrent PTB overall, however the association observed with VLDLNMR particle size is suggestive that PTB may be amenable to lifestyle, nutritional, or pharmacologic interventions.