I've heard that women are meant to wait until after the first trimester to reveal that they are pregnant. (One rabbi I heard say they should wait even beyond, if possible.) The idea being to avoid drawing the evil eye from others, by which I'm referring to Artscroll's Talmud's explanation: a negative spiritual force that can arise as a result of causing jealousy in others, leading to the Heavenly Court questioning anew someone's aptitude for receiving a bracha.
I have a few questions about that:
- When does the 'first trimester' start, in this regard? Modern medicine counts the start from the first day of the last period before a woman conceived. (Which seems weird - saying someone's pregnant during a time when they were on their period. Any doctors who want to elaborate?) If you count one trimester from that date, you get a date about two weeks earlier than if you count from the mikveh night following the last period.
- Also, is 'one trimester' 12 weeks? 90 days? From the date a woman becomes pregnant (e.g. 15 Nisan) to the same date three calendar months later? Something else?