Introduction Fetal cells persist in mothers for decades after delivery; in a phenomenon called fetal microchimerism. The aim of this study was to determine whether microchimeric fetal cells improve wound healing after pregnancy.

Methods Skin biopsies were taken from caesarean sections scars and compared with laparotomy wounds in nulliparous women. Blinded histological analysis of scar tissue by a consultant Histopathologist, in H&E stained sections, measured differences in wound healing between the groups. Elastin staining quantified the amount of elastic tissue in the scars. XY-FISH (fluorescence in situ hybridisation) was used, in multiple tissue sections from 65 patients, to locate and quantitate microchimeric male presumed-fetal cells.

Results H&E comparisons suggested that wound healing improves after pregnancy. There were few differences between healed scars and uninjured skin, with only increased vascularity and increased number of fibroblasts in the scarred tissue. Elastin stained up to 50% positive in the scar tissue, confirming that the scar not only restores normal structure but almost normal function after pregnancy. XY-FISH confirmed the presence of isolated 0–9 male fetal cells per section in the epidermis of the healed CS scars from only those women who had their first male child by CS. To investigate the fetal cell type responsible, combined FISH and immunostaining experiments are still in progress.

Conclusion This study may demonstrate that wound healing is more fetal-like (scarless) after pregnancy and provide information on the long-term benefits of pregnancy.