How many weeks pregnant am I?

[CSSL7]

I literally cannot comprehend how the NHS uses your first day of last period as a way to measure your gestation.

for example, my LMP was 10th September. I didn’t ovulated until CD18. The NHS puts my due date as June 16th so I’m technically six weeks pregnant on Tuesday.

going off ovulation (OPK sticks and bbt) I am only five weeks yesterday. So that’s literally almost one week difference.

I don’t understand how my baby’s development is going to be judged off a 14 day cycle, so when I get scanned they’ll say they’re measuring a week behind.

does anyone else have this issue?

so I’m supposed to consider myself and symptoms as 6 weeks tomorrow when actually I’m only five weeks and one day.

It’s measured right from when the egg is coming down the tube etc so yes you take it from lmp and that’s accounted for with symptoms etc then at your dating scan you’ll get a more accurate due date

If you ovulated on day 18 then it’s only 4 days behind. The nhs system assumes ovulation on cd14 really when it goes off the lmp. 28 day cycle, ovulate on day 14.

I tracked my ovulation with my ds and my current pregnancy. The 12 week scan had surprisingly been accurate- both times they have only put me 2 days ahead of when I ovulated. In the grand scheme of things it doesn’t matter. I say that as my son was born at 35+0 from their view so technically 34+5! (He’s now an energetic fully healthy 18 month old).

With my son I ovulated late on day 24. I had a private scan at 9 weeks and my midwife listened and put my dating scan back a bit (even if she hadn’t I would have just had my scan at 12weeks rather than 13+3). As long as it’s <14 weeks for the combined test it doesn’t matter. I think that’s why they aim for 12-13 weeks for the scan so then if it’s 11-14weeks it’s still in range for the majority.

Im now 13+6 with this pregnancy. I had a epu scan at 8 weeks exactly due to intense pain and they put me back 1 day to 7+6. By my 12 week scan at 12+1 they put me forward 2 days to 12+3.

The purpose of the lmp is to give a rough idea of when to book your dating scan. Then that date becomes the exact date you will give birth until the end when there's a 5 weeks window of normal gestation. Those few days that felt so important feel less important when it's the difference between 39+4 and 40+2.
In terms of symptoms they are so varied from pregnancy to pregnancy. One person might only get a few days of sickness at 7 weeks where as another would be bed bound at 5 weeks.

They're aware that cycle lengths differ and people can ovulate early or later. My EDD was adjusted to be a week later at my dating scan. Both the 12 and 20 week scans have windows of a few weeks where they're done, so being under a week out by your dates isn't a problem. No-one says anything about the baby measuring small or behind, they just adjust your dates and only use the due date measured in the scan. Personally on my dates, I think my original due date was more likely to be accurate than the new one done by measurements.

Guys you have all just eased my overthinking mind. All make so much sense. Thank you so much!! And also means I’m technically six weeks tomorrow which is exciting! Thank you for taking the time to comment. I knew it was somewhat of a silly question but I just couldn’t wrap my head around it!

Tysm!!!!

I have long cycles but knew when I ovulated so I just told my midwife that my LMP was two weeks prior to ovulation and I have 28 day cycles. I'm almost 10 weeks now but if I went off LMP would be 12!