What is more accurate? Date of conception or dating ultrasound?

[Mad Scientist]

Both my ultrasounds were out by 10-12 days (saying i was due later than i thought with my dates). DD1 came a month before my date and six weeks before my u/s date but she definitely wasn't six weeks early. Dd2 came right on MY due date, 10 days before my u/s due date. I'd be putting faith in your due date seeing as you were so sure of conception

[BellyBelly]

Your own menstrual cycle, always. Machines are based on averages and mathematics. We all have unique cycles hence why we never give birth on the guess date either.

[Faithful Mumma]

Yep, I would go with your conception date. I totally understand where you are coming from though....my DS was 11lbs 2 oz, although he was two weeks late (going by my conception dates).

[~Kim~]

DTD date isn't always the same as O date though. Do you know when you O'ed cos that could be the 5 days difference IYKWIM?

[Twin Sister]

I would say U/S due date since ovulation day and BD day are not necessarily the same. When I was PG with DS my LMP due date was 6 days before my U/S due date and he was born on his U/S due date.