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is very common cause for worsening the vitiligo
there are many theory to explain the cause of vitiligo .
its not proven that it is heredity condition ,but we see that in some cases it runs in heredity
unfortunately no doctor can predict that baby will get the vitiligo or not
but be relax because we rarely see transmission to mother to baby ,its more from father to baby .
just good thing you can do is avoid stress
i hope i answered your question