Conception date help

[Annonymous24]

I need help trying to figure out when I most likely conceived.

I have irregular periods with my last one being 20th September, this would give me and EDD of 26th June however my ultrasound has given me the due date of 3rd July.

Is the ultrasound based from the likely conception date? As this would mean I conceived around 27th September which is only a few days after my LMP ended. Or do I need to add the standard 2 weeks on to that and then I most likely conceived around 11th October?

Either way am I going to be 41 weeks pregnant rather than the standard 40 as I at least know for certain the date my LMP was and that’s 41 weeks exactly from my given due date.

Very confused any advice would be appreciated as do not have another midwife appointment for a while to help clear it up.

The twelve week scan will give you the estimated due date and that’s the date you work with.If they’ve given you the 26th of June then go with that date, you don’t need to add any weeks onto that. The scan measures the size of the baby- sometimes your baby can grown quite quickly in the first 12 weeks and the due date is moved forward or they grow slowly and the due date is moved back.

Due date is calculated from your growth scan - they look and the size and development of the fetus to determine age

Pregnancy is calculated from the beginning of your last period. So for the first few weeks of pregnancy although this is included in the calculation, you haven't actually conceived yet.