Mid-pregnancy levels of angiogenic markers as indicators of pathways to preterm delivery

Objective: To determine whether mid-pregnancy levels of angiogenic markers were associated with increased risk of preterm delivery (PTD). Methods: We studied a subcohort from the Pregnancy Outcomes and Community Health Study for whom mid-pregnancy angiogenic markers (soluble fms-like tyrosine kinase-1 [sFlt-1], soluble endoglin [sEng] and placental growth factor [PlGF]) and covariate data were available (N = 1301). Angiogenic marker levels were grouped as high/not high (sFlt-1 and sEng), low/not low (PlGF) and high/intermediate/low (sFlt-1). Associations between levels of angiogenic markers and PTD/PTD subtype were determined for women who were nonsmokers during pregnancy (N = 933). Results: Low PlGF and high sEng were associated with medically-indicated PTD and PTD <35 weeks, largely due to preeclampsia (PE). Excluding PE and small-for-gestational-age infants, low sFlt-1 was positively associated with medically-indicated PTD. Conclusions: Among nonsmokers, mid-pregnancy levels of angiogenic markers may mark multiple pathways leading to PTD, only one attributable to PE.