Objective: To assess whether circulating IGF-I and IGF-binding protein-1 (IGFBP-1) in the first and second trimester are associated with subsequent risk of preterm and term preeclampsia.
Methods: Nested case-control study within a cohort of 29 948 pregnant women. Cases were women, who later developed preeclampsia, and controls were randomly selected women, who did not develop preeclampsia. IGF-I and IGFBP-1 were measured with ELISA in maternal blood samples that were collected in the first and second trimesters. We assessed associations of IGF-I and IGFBP-1 concentrations with later development of preterm (before the 37th week of gestation) and term preeclampsia.
Results: An increase in IGF-I from the first to second trimester was associated with higher risk of preterm preeclampsia; the odds ratio (OR) for the highest compared with lowest quartile of increase was 4.9 (95% confidence interval, 1.1-21.8). Low concentrations of IGFBP-1, both in the first and in the second trimesters, were related to higher risk of term preeclampsia (OR 4.0, 95% confidence interval, 1.9-8.4) and moderately increased risk of preterm preeclampsia (OR 2.3, 95% confidence interval, 1.2-4.4).
Conclusion: The higher risk of preterm preeclampsia related to IGF-I increase may reflect placental disease, whereas low concentrations of IGFBP-1 associated with term preeclampsia may reflect maternal metabolic aberrations, indicating different etiologies in preeclampsia.