Association between serum soluble fms-like tyrosine kinase-1 and the central choroidal thickness during pregnancy: a prospective study

OBJECTIVE: To investigate the association between serum soluble fms-like tyrosine kinase-1 (sFlt-1) and the choroidal structure during the pregnancy. METHODS AND ANALYSIS: This prospective study enrolled 24 eyes of 12 consecutive healthy pregnant women. Each participant was evaluated during the first, second and third trimester of pregnancy and the postpartum period. The central choroidal thickness (CCT) and Choroidal Vascular Index (CVI) were measured using enhanced depth-imaging optical coherence tomography. Moreover, serum sFlt-1 and vascular endothelial growth factor (VEGF) concentrations were measured manually using ELISA. The association between choroidal structural parameters and serum sFlt-1/VEGF was analysed using a linear mixed model. RESULTS: The CCT was significantly thicker in the second and third trimester than the postpartum period (p<0.05). In contrast, there was no significant difference in the CVI throughout pregnancy or the postpartum period. Serum sFlt-1 levels were significantly higher during pregnancy than the postpartum period (p<0.05), whereas the serum VEGF levels were significantly lower during pregnancy than the postpartum period (p<0.05). Furthermore, serum sFlt-1 levels were significantly associated with CCT throughout pregnancy (p=0.011, linear mixed model). On the contrary, sFlt-1 levels was not associated with the CVI during the pregnancy. CONCLUSION: Our results suggest that serum sFlt-1 might have an influence on the choroidal thickness during the pregnancy.