if you have long cycles why do they still count baby from gestation period?

[wantbabiesnow]

Ok so I don't understand why GESTATIONAL date is so important

I have 33 day cycle

Say another lady has a 37 day cycle

Say lady C has 28 day cycle

All ladies have their period on Jan 1
Lady C ovulates Jan 14
I ovulate Jan 17
37 day cycle lady Ovulates Jan 19th

Say all women get pregnant

Wouldn't an ultrasound on Feb 5th show very different fetal size for each of these women?

The Drs would say all women are just as far as eachother in pregnancy based off the date of the last period.. BUT there's a 5 day difference in ovulation.

Is the late ovulator baby supposed to turbo speed grow to catch up to the growth of the 28 day cycle ladies baby?

Am I stupid?

 

[Flueky88]

Before the dating ultrasound they use lmp to determine your due date/weeks. It's just "easy" but certainly not accurate. I O on CD18 not CD14 so my "weeks" is inaccurate by lmp.

With my first pregnancy the adjusted my due date after doing the ultrasound. I Od on Cd 21 or 22 when I conceived that time.

They use lmp because not all women know when they O and so it's just an "easy" thing to date from lmp.

 

[MissMarpleFan]

I have a long cycle and so I am always over a week behind where they think I should be. They adjust the due date based on the size measurement of baby.

 

[Curlymikes]

My dr goes by your last period until they do an ultrasound. They also test your blood hormone level and watch it go up to over 2000 then they will give you an ultrasound which is usually around 6 weeks. Then based on thst ultrasound they get your newdue date and base everything off that. I ovulated 2 weeks late this cycle thst i got pregnant so at first they thought i was 2 weeks further along. Then they corrected it and never mentioned it again.

 

[Mummafrog]

Last menstrual period calculation is supposed to include cycle length!
To get a more accurate first due date from the doctor if they're not using cycle length, say that your lmp date is the date that was 14 days before O date and you have a normal 28 day cycle and it will be calculated correctly

 

[coquis224]

I know what you mean! my periods are usually 5 weeks apart and I'm always a week behind by what the dr says. It's frustrating.

 

[missielibra]

I'm going with what others have said. All they had to go with at first is your lmp. Usually that's why your date changes after the first ultrasound.

Because I mean, unless you can 100% pinpoint, you wouldn't really know when you ovulated.
Let's say I'm 28 days, but I ovulate at CD 17 all the time.
And you're 33 and you ovulate at CD14. We can have different luteal phases too. And then, your baby would be conceived earlier than mine, despite a longer cycle. Some ladies have 9 days luteal phases and still a 28 days cycle. There is so many variables, so they use what they have at first, and then change your date accordingly with your first ultrasound. But yes, at the very beginning, you'd all sorta would have a same due date, but it's not set in stone.

Actually, there's a girl here she was ahead of me (cycle, BFP, DPO) and you see, now I have a due date early than hers because it got changed at my ultrasound. So they do adjust.

 

[Buttercupbabi]

My periods are all over the place!
I came on the Tuesday 20th March and came off Tuesday 27th March. Got a positive OPK Sunday 01st April with a due date being 25 Dec...

Went to my dating scan and baby was 5 days ahead? Which would mean this baby was conceived the day I came off my period but we didn't even do the DD till the Friday and Sunday lol and from what scientist say the egg is liable for a 24hours only!!!

I think take it with a pinch of salt, at your dating scan they will tell you what they think and go with that date xx