Results

Infants born by pre-labour CS had significantly decreased levels of the inflammatory markers (CRP, MCP-1, IL-18) and the stress-marker HSP70, and significantly increased levels of the growth factors (VEGF and EGF) compared to infants born by VD. Comparing pre-labour CS with in-labour CS showed a similar pattern: CRP, MCP-1 and HSP70 were significantly decreased, and VEGF was increased, in infants born by pre-labour CS compared to infants born by in-labour CS. When comparing in-labour CS to VD, only CRP was significantly different. We found no delivery form depending differences in neonatal levels of the neurotrophic factors (S100B, BDNF and NT-3), or the anti-inflammatory marker sTNF RI (Figure 1).
Most biomarkers were different between genders: males had significantly lower levels than females of the anti-inflammatory marker sTNF RI, the growth factors (EGF and VEGF), and the neurotrophic factor BDNF. The inflammatory markers CRP and MCP-1 were higher in males compared to females. Delivery form has an overall effect on S100B and IL-18 in males, but not in females. The gender differences were generally more significant after VD (CRP, MCP-1, sTNF RI, EGF, BDNF, VEGF), than after in-labour (CRP, BDNF) and pre-labour CS (CRP, VEGF) (Figure 2).
We saw an overall increase of the inflammatory markers CRP, IL-18, and MCP-1 from GA 37-42, and a decrease of the anti-inflammatory marker sTNF RI. The stress-marker HSP70 decreased from GA 38-40. The growth factors EGF and VEGF, and the neurotrophic factor S100B, decreased overall in samples from GA 37 to 42, while no overall significant difference was found for the neurotrophic factors BDNF and NT-3 (Figure 3).
There was a significant difference in infants’ birth weight between delivery forms, where the heaviest infants are born by in-labour CS and the lightest by pre-labour CS (table 1). Birth weight was included in the first calculations, but did not make any differences as long as GA was included in the final model, and thus were excluded in the final calculation. The maternal BMI was higher for mothers in the CS group (no matter type) compared to VD, and the maternal age was higher in the pre-labour CS group compared to the other groups. Neither of the factors could explain any of the differences found in the biomarkers. The age at sampling could not explain the differences observed in biomarkers between the different delivery forms, neither could it explain the differences in males and females. There were significantly more cases of PROM before in-labour CS and VD. Removing all cases with PROM did not change the results.