Has the method of calculating changed?

[endofthelinefinally]

Recently I have seen discussions when posters say they are 3, 4 weeks pregnant. I am a retired midwife and admittedly probably out of date. However, EDD was always calculated from the first day of LMP. So generally 5 weeks would be the earliest one would get a positive test.
Can anyone explain this 3/ 4 weeks pregnant thing and is this universal now?
Thanks.

I tested positive with DS 6 days before my period was due, so yes, 3 weeks pregnant.
Makes for a long pregnancy.

Nope it hasn’t changed just tests can detect it earlier now. I found out I was pregnant at 3 weeks after my last period. But calculated as 3 weeks 1 day pregnant as I ovulated a day earlier, I know my dates are exact as I had fertility treatments

Two weeks before conception not beyond.

Yep calculation method hasn't changed, everyone still goes off LMP. I got my BFP at 3 weeks and 5 days after LMP because I was impatient and tested early, a few days before the expected first day of my next period.

@lucymagoo

I was 3 weeks 1 day from LMP when I found out, by my now adjusted dates from my dating scan I was exactly 4 weeks pregnant on that date so 5 weeks definitely isn't the earliest

I was also 3+1 (by lmp) when I found out with a positive test (6 days before af was due). Wasn’t a particularly sensitive test. Just an easy at home cheapie. Confirmed the next day with a strong line on a first response.

Those saying 3/4 weeks are still using the old method. Pregnancy tests can be used 5 days before period is due so you would find out at just over 3 weeks. 5 weeks would be a week after period is due and people are less likely to wait until then to test if they are actively trying.

I guess earlier testing is both good and bad. There will be more chemical pregnancies and very early miscarriages discovered where in the past they would have just been a "late period", potentially more disappointment. OTOH, there are advantages to knowing very early I suppose.

@Babdoc

Retired doc here. Yes, OP, I’ve noticed these strange timings on here too! I don’t think our colleagues have changed anything, it’s just ignorance on the part of patients. I’ve had to explain to some who were puzzled why term pregnancy is described as being 40 weeks, when that would be “ten months”! I assume the posters are counting from the theoretical date of their missed period, not the actual known date of their LMP.

Retired doctor or not, I need to correct you here. It’s certainly not the ignorance of patients. It’s the knowledge that we now have that previous generations may not have. We are acutely aware that the gestational period is counted as 40 weeks which starts at the first day of the last menstrual period. None the less, it is quite common now for sensitive pregnancy tests to detect HCG at 7 or 8 DPO which is usually 3 weeks pregnant based on a woman who ovulates on day 14 of their cycle.

So no, we are not counting from missed period, we’re just much more educated than you may believe even if we don’t have that medical degree on the wall.

I ovulated on day 12 of my cycle. I tested positive 9 days after that. That made me 21 days pregnant, or exactly 3 weeks from date of LMP when I found out, so 3 weeks pregnant. I am so surprised to see medical professionals questioning this.

On average the day when you test ( day of missed period) would be 4 weeks.

I tested 5 days before I was due on so that would have been 3 weeks plus however many days.

And 5 weeks is typically when maybe the peeing on a stick thing wasn't such a crAze haha! And people actually waited a good few days to a week for a missed period! ☺️

It never adjusts dates! Just because you test early... anyone who is say 5 weeks would also have been 3 weeks at some point! Everyone ovulates slightly different.

At my dating scan and an early scan at 8 weeks matched to the exact date ( give or take a day) of when I ovulated.

Everyone is individual and has different ovulation dates and length of cycle.

I can only speak for myself where I know my regular cycle length etc x

I tested positive at 3+5, I even knew exactly when we dtd which was 11 days before I got the positive, my cycle was always 31 days but I ovulated on day 15, I had been tracking fertile period with ovulation tests & temperature tracking.

I had IVF so knew exactly how pregnant I was. I had ashermans and no periods (hence the ivf) so going by the date of my LMP my baby would have been several years old at 4weeks pregnant!