Quotation zu Jirmejahu 18:3

And God remembered Rachel (Gen. 30:22). May our master teach us whether a man may recite the prayer “May it be Your will that my wife give birth to a son” if she is already pregnant. Our masters teach us: The man who prays “May it be Your will that my wife give birth to a son” when she has already conceived is uttering a vain prayer (and is taking the Lord’s name in vain).