Why keep pregnancy 'secret' for the first trimester?

[spamforbrains]

A second factor is - arguably - even more grisly. It is at the 12-week scan that we find out whether or not the child has any obvious pending birth defects (and so, implicitly, gives the parents the option of deciding whether or not they want to abort the child). We therefore delay telling the world at large about pregnancies before this period, because ‘We decided to abort our kid because we can’t deal with having a child with Down’s Syndrome’ isn’t the sort of thing you would want to post on Facebook.

Is this 12-week thing universal, or specific to our corner of the world/socioeconomic demographic? And for those who observe it, why?

You frequently cannot actually tell until around 20 weeks if the fetus has serious abnormalities. Therefore the “keep it secret” is almost certainly due to the incredibly high rate of natural early pregnancy losses. Every woman not on some type of hormonal birth control that prevents ovulation will experience multiple “miscarriages” throughout life, often without ever realizing that anything happened. So announcing a pregnancy prematurely will often lead to many annoying explanations to people that yeah, it wasn’t really a pregnancy, it was a biological accident.