What due date calculation is more reliable?

[PrEgSeCoNdJoY]

most drs do go by lmp some use a wheel to tell them the due date and others use the old fashioned way you take your lmp subtract 3 months and add seven days and this should be your due date!! With Valerie my doc was right on using this method!!! good luck ladies!!

 

[x-amy-x]

I had my last baby on her due date according to LMP xx

 

[staceymy]

Docs & MWs go from first day of last period for estimated due date. Then get actual due date at dating scan. Its just easier for them to work it out that way.

 

[Seraphim]

We've used OV date because we knew it.
I guess it's not always available, so they opt for LMP.

Docs don't usually expect most women to know their O date (unless they're charting), so that's one of the reasons they tend to go by LMP only. I think O date is more accurate, though. LMP doesn't take into account the length of a woman's cycle - which often varies far from the average 28 days. If you ovulate 3 or 4 weeks into your cycle - say on CD24 or CD30, then to me, it would be more accurate to go by O date.