When to Announce Pregnancy in Islam
Question

My wife recently became pregnant for the second time and we want to announce it to everyone. Is it permissible to announce it right away or is there a waiting period of three months before announcing pregnancy? Could you please tell me what the ruling is on that.
Praise be to Allah.We ask Allah to bless you with righteous offspring and to bless this child. 
There is nothing wrong with telling other people about the pregnancy after you find out about it, and it is not essential to wait until three months have passed. Rather it is permissible to tell others before then, but you should limit that to family and close friends only. This is a general principle which should be paid attention to when telling others of blessings. The news should be given only to those who wish good for you and will rejoice over it, so as to ward off the evil eye and destructive envy. 
The evidence for that is the words of the Prophet (peace and blessings of Allah be upon him): “Be discreet in order to achieve what you want, for everyone who is blessed is envied.” (Narrated by At-Tabarani and Abu Nu`aym; classed as authentic by Al-Albani in Sahih Al-Jami`, no. 943) 
For more details, please refer to the following answers: 82465 , 119767 , 12368 , 7889 , 12287 , and 88734 .            
And Allah knows best.