Microchimerism: how pregnancy changes the mother’s very DNA.

(…) another body of research has found that foetal cells can protect the mother. They appear to congregate at wound sites, including Caesarean incisions, to speed up healing. They participate in angiogenesis, the creation of new blood vessels. A recent survey of the immunological implications of microchimerism in Nature Reviews by researchers at the Cincinnati Children’s Hospital asserts that these cells ‘are not accidental “souvenirs” of pregnancy, but are purposefully retained within mothers and their offspring to promote genetic fitness by improving the outcome of future pregnancies’.