It can be for the first child.Let the child know there's a baby in "there" and that is a little brother or sister.I wouldn't say anything until the mother is somewhat showing or the baby moves.Then let your little one feel it move and watch her belly grow.Telling the child all along the baby's growing and pretty soon the doctor will take it out.Stress how important it will be for the older child to "help" and how excited you are to have another baby to love.Make sure you say things like I hope the baby is beautiful like you etc.
On you as a couple it may not be much of a stress or it may.Depends how you are as a couple.My stress level was fine with the children.It all depends on a HUGE sense of humor while you raise kids.Believe me.

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