Birth
One can hear the sound of joyfulness by heavenly beings from the city of Medina. There is a ray of light beaming out of the simple and affable home of Imam Kazem (Peace Be Upon Him). The stars have become brighter and the moon is shining like the sun. The sound of crying has broken the silence of the skies and has terminated the lovely anticipation of a father and has created a smile on the shining lips of the seventh infallible Imam and brought about a companion for Imam Reza (Peace Be Upon Him) to become another Zeinab for another Hussein. Yes, Medina is filled with the pleasant scent of Fatima Ma'soomah (Peace Be Upon Her). End of anticipation Since Imam Sadiq (Peace Be Upon Him) prior to the birth of Imam Kazem (Peace Be Upon Him) had recounted the birth of Hazrat Ma'soomah (Peace Be Upon Her), the household of Imam for more than 45 years were awaiting the birth of this noble lady. What adds to the significance of this anticipation is that Hazrat Najmah was the mother of Hazrat Reza and Hazrat Ma'soomah (Peace Be Upon Them) who had only two children. Imam Reza (Peace Be Upon Him) was born 25 years prior to the birth of Hazrat Ma'soomah (Peace Be Upon Her). Hence, Hazrat Najmeh and Imam Reza were awaiting the birth of the noble lady during the said period of time.
source : www.tebyan.net