Yeah defo trust they know what they're doing, just me being me and wondering how or why.. haha lol thanks again for messages xx

It doesn't matter when you DTD because it still takes time for the sperm to reach the egg, etc. Ovulation occurs roughly 2 weeks after the start of your last period but there's no way to tell for certain what day you conceived. That's why your due date is calculated by the first day of your last period. But at the 12 week and 20 week scan they can tell if the dates are correct. For example, my 20 week scan little one measured 10 days bigger even though I definitely knew the first day of my last period. But the ultrasound technician said that they have to be over 10 days bigger at 20 weeks before your due date gets changed and because he was spot on at my 12 week it just means he's a bit bigger. It is confusing but the midwives should know what they're doing xx

nevermind lol x

Yeah that would make sense but they havnt worked it out like that.. if they did then due date would be more like 19th September

They go from when you ovulate cause that's technically the start of the baby whether fertilised or not. Xx

Because on average people with a 28 day cycle ovulate day 14 or there abouts. So they use your last period to work out when that is.

Yeah if worked out from start of last period then due on 7th September bit at scan said 5th

thanks for your messages though. appreciate it x

Also due date changes once you have a scan & they go by babies size I think...

but they worked it out from start of last period.. not when I ovulated that's why confused

It's calculated from when you ovulate so they need to know the date of your last period :)