It is part of etiquette to refrain from asking people about their private affairs
Question

Everyone ask me and my wife these question Are you pregnant ? Any plans? update? due date ? and they do never ending guessing and all these sort of questioning etc. sometimes also ask in public in high voice. This put us in very embarrassing situation, we both are very shy. we would like to ask Is it permissible for people to enquire about things of such a private nature, Do we require to announce pregnancy, Is it a public concern or affair, We believe it is private thing and want to keep private till the end, we Believe once Allah bless Us with child, we will anounce the birth. We believe it is against modesty and have privacy issue and there could be many implications. One of the brother was very upset when I told him not to ask, Do I have to tell him that my wife is prgnant now and expecting. Please advise with refernces.
Praise be to Allah.Many people overstep the mark in speaking to others, and they do not observe any good manners or modesty. The reason for that is ignorance and a lack of interest in developing a good attitude or good manners. That includes what many people do of interfering in that which does not concern them and asking about people’s private affairs. 
It was narrated from Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said:  
“Part of a person’s being a good Muslim is leaving alone that which does not concern him.” Narrated by al-Tirmidhi (2317); classed as saheeh by al-Albaani. 
Ibn Rajab said in Jaami’ al-‘Uloom  wa’l-Hikam (1/114-116): 
This hadeeth represents an important principle of etiquette. Imam Abu ‘Amr ibn al-Salaah narrated that Abu Muhammad ibn Abi Zayd, the imam of the Maalikis of his time, said: All good manners and etiquette are based on four ahadith: 
The words of the Prophet (peace and blessings of Allah be upon him): “Whoever believes in Allah and the Last Day, let him speak good or else keep silent.” 
And the words of the Prophet (peace and blessings of Allah be upon him): “Part of a person’s being a good Muslim is leaving alone that which does not concern him.” 
And the words of the Prophet (peace and blessings of Allah be upon him): “Do not get angry.” 
And the words of the Prophet (peace and blessings of Allah be upon him): “The believer loves for his brother what he loves for himself.” 
The meaning of this hadeeth is that part of his being a good Muslim is that he refrains from doing and saying that which does not concern him, and he does and says only that which does concern him, i.e., he has something to do with it. Mostly what is meant by refraining from that which does not concern him is guarding his tongue against idle talk. 
In al-Musnad (1/201) it is narrated from al-Hasan that the Prophet (peace and blessings of Allah be upon him) said: “Part of a person’s being a good Muslim is talking little about that which does not concern him.” [al-Arna’oot said: It is hasan because of corroborating evidence]. 
‘Umar ibn ‘Abd al-‘Azeez (may Allah have mercy on him) said: The one who regards his words as being among his deeds speaks little except about that which concerns him. And it is as he said. Many people do not regard their words as being among their deeds, so they are careless and do not watch what they say. But Allah has stated that there is nothing good in much of what people talk about amongst themselves. He says (interpretation of the meaning): 
“There is no good in most of their secret talks save (in) him who orders Sadaqah (charity in Allah’s Cause), or Ma‘roof (Islamic Monotheism and all the good and righteous deeds which Allah has ordained), or conciliation between mankind” [al-Nisa’ 4:114]
al-Tirmidhi and Ibn Maajah narrated from Umm Habeebah that the Prophet (peace and blessings of Allah be upon him) said:  
“Everything that the son of Adam says is counted against him and not for him, except enjoining what is good and forbidding what is evil, and remembering Allah, may He be glorified and exalted. 
[It was classed as da’eef by al-Albaani in Da’eef al-Tirmidhi]. 
Some people stated in the presence of Sufyaan al-Thawri that they found this hadeeth strange, and Sufyaan said: Why do you find this strange? Allah says (interpretation of the meaning): “There is no good in most of their secret talks save (in) him who orders Sadaqah (charity in Allah’s Cause), or Ma‘roof (Islamic Monotheism and all the good and righteous deeds which Allah has ordained), or conciliation between mankind” [al-Nisa’ 4:114]. 
Al-Tirmidhi narrated that Anas (may Allah be pleased with him) said:  
One of the companions of the Prophet (peace and blessings of Allah be upon him) died, and a man said: Glad tidings to him of Paradise. The Messenger of Allah (peace and blessings of Allah be upon him) said “You don’t know; perhaps he spoke of that which did not concern him, or he was miserly with something that he could do without.” Classed as saheeh by al-Albaani in al-Silsilah al-Saheehah (3103). 
Reports with similar meanings were narrated via numerous isnaads from the Prophet (peace and blessings of Allah be upon him) and in some of them it says that the man was killed as a martyr. End quote. 
Al-Munaawi said in Fayd al-Qadeer (7/3): 
It is possible that what is meant is asking a man too many questions about his situation, which includes asking about that which does not concern one. That also may lead to embarrassment for the one who is being asked, because he may prefer not to tell him about his situation, and if he tells him he may feel upset about that, but if he lies to him or tries to give indirect answers he may still feel upset, and if he ignores his question that will be bad manners. End quote.
There are reports from some of the salaf which point to this matter of etiquette: 
‘Amr ibn Qays al-Malaa’i said: 
A man passed by Luqmaan and there were people with him. He said to him: Aren’t you the slave of such and such a tribe? He said: Yes. He said: Didn’t you used to farm by Mount So and so? He said: Yes. He said: Then how have you ended up as I see you? He said: Speaking the truth and keeping silent for a long time about that which does not concern me. 
Muwarriq al-‘Ijli said:  
It is something that I have been seeking for so many years, but I was not able to do it, but I will never stop looking for it. They said: What is it? I said: Refraining from that which does not concern me. 
Both reports were narrated from Ibn Abi’l-Dunya. 
Abu ‘Ubaydah narrated that al-Hasan al-Basri said: One of the signs of Allah’s turning away from a man is that he becomes involved in that which does not concern him, as a sign that Allah, may He be glorified and exalted, has left him to his own devices. 
The above shows people how to adopt this important attitude and etiquette, and how to interact with one another in accordance with the guidance of the Prophet (peace and blessings of Allah be upon him) and the righteous. 
For more information on this sublime etiquette that is lacking among many people, see the commentary on hadeeth no. 12 in Jaami’ al-‘Uloom by Ibn Rajab al-Hanbali (may Allah have mercy on him), where there is a useful discussion under the heading: Mu’allim fi tarbiyat al-nafs min husni islaam al-mar’i tarkuhu ma la ya’neehi, written by ‘Abd al-Lateef ibn Muhammad al-Hasan, in the al-Bayaan book series published by al-Muntada al-Islami in London.  
And Allah knows best.