Mid-Trimester Maternal Serum Alpha2-Macroglobulin and Pregnancy Outcome in a Non-Indigent Population

Abstract

Alpha2-macroglobulin is a 725,000 d glycoprotein involved in proteolytic enzyme inhibition and immunoregulation. Previously, we demonstrated an association between increased maternal serum alpha2-macroglobulin and intrauterine growth retardation (IUGR) in two distinct population samples. In this study, we sought to determine whether elevated maternal levels of alpha2-macroglobulin were associated with IUGR, preterm delivery (PTD), or low birth weight (LBW) in a non-indigent population. We measured alpha2-macroglobulin concentrations in serum obtained at the time of maternal serum alpha-fetoprotein testing in a sample of 549 patients enriched for IUGR (14%), PTD (24%), and cigarette smoking (16%). Subjects were selected from local private care settings. Mean serum alpha2-macroglobulin concentration (± standard deviation) was 3.16 (± 0.85) g/L. Similar to our previous studies, in the upper quartile of alpha2-macroglobulin, 20.4% of subjects delivered a growth retarded infant vs. 12.4% in the lower three qua...