I remember learning that before a certain point in pregnancy the phrase “X weeks pregnant” is a meaningless term. What point is that?

Yeah I get you. I mean surely most people would just say "months pregnant".

I meant: BEFORE a certain week of pregnancy, saying “X weeks pregnant” isn’t a thing. I BELIEVE it’s 2 weeks. (IOW a woman wouldn’t say “I’m 2 weeks pregnant)

According to Google, most women don’t know until week 4, AND pregnancy isn’t detectable until a missed period.

Oh right

Going by weeks is more for the medical side of it, each week determines development

1) "Weeks pregnant" is defined as "weeks since last period".
2) A woman is fertile for a window of time during each menstrual cycle.  Let's say it's 1-3 weeks after the last period with 2 weeks after being the most fertile point.
3) A fertilized egg does not implant into the walls of the uterus until some period of time after an egg is fertilized (and may never implant).  Let's say that's 1-2 weeks.
4) Bleeding can occur during implantation, which is around the time a period would have occurred anyway.

Combining these facts, conception could have occurred as recently as 3 weeks ago and implantation as recently as 1 week ago for a woman who is nominally "6 weeks pregnant" but plausibly has no indication she's even pregnant.

(September 1, 2021, 5:29 pm)Justpreggin 1) "Weeks pregnant" is defined as "weeks since last period".
2) A woman is fertile for a window of time during each menstrual cycle.  Let's say it's 1-3 weeks after the last period with 2 weeks after being the most fertile point.
3) A fertilized egg does not implant into the walls of the uterus until some period of time after an egg is fertilized (and may never implant).  Let's say that's 1-2 weeks.
4) Bleeding can occur during implantation, which is around the time a period would have occurred anyway.

Combining these facts, conception could have occurred as recently as 3 weeks ago and implantation as recently as 1 week ago for a woman who is nominally "6 weeks pregnant" but plausibly has no indication she's even pregnant.

TY for that refresher! Biology is almost 30 years in my rear view mirror. And I was a TERRIBLE science student.

In the 1980s, I never recalled women themselves said they were weeks pregnant, but since 2000, they went by that "X weeks" instead of "X months". It is a form of political correctness, also they want women to be Ms. not Mrs or Miss and to not assume an unborn baby is a "boy" or "girl" as well just refer it as a "fetus". I'm on the center-Left and consider myself a feminist in some way, I notice women are fighting for the right to drink alcohol and smoke cigs, they point out the father's sperm could have damaged DNA to produce birth defects instead of what the mother does during pregnancy, and these women also said "don't call us big, don't touch our belly and don't tell us pregnancy stories". Pregnant women fought for the right to work in any job they want, to exercise and even have sex, but she and her partner should talk about this private issue among themselves, I had it with PC-ness, "social justice" and "everything's sexist/hate/offensive/too political/too controversial". And let's not start on the issue of abortion, the most triggering issue among a large percentage or majority? of (cis-) women.

I’d argue that it’s more scientific as a ‘month’ is an inconsistent measure of time (Sometimes 30 days, sometimes 31, sometimes 28 and occasionally 29). It can give you a general idea of progression but not specific.