התינוק שלי

האישה שלי ואני מצפים לילד החמישי שלנו להיוולד. אימא שלי היא המילדת שלנו אבל היא אמרה לי ״אתה יילד את התינוק שלך!״. המלים שלה. לא תודה!

I'm guessing that you meant this: "My wife and I are expecting our fifth child to be born.  My my is our midwife, but she told me, "you deliver your own baby!"  Her words.  No thanks.  

The infinitive of "to be born," which is what I assume you meant by לנולד, is l'hivaled (להיוולד).  Because אימא actually means, "the mother," in Aramaic-- אם + -א --it is often written without the definite article.  Stylistically, it contributes a little more to the casual tone, and the humor, to say "אימא שלי היא," instead of "האימא שלי היא."  Also, unless I misinterpreted this, you meant that your mother was jokingly telling you to "deliver your own baby!"  If so, the imperative is needed, which in this case would be yaled! (יילד!), not m'yaled (מיילד).  

Hope this helps, and congratulations!