Do you calculate based on LMP or conception?

[Tonka106]

Hi all! This is my first post in this forum in 9 years!! Just found out that I'm pregnant with baby #2. I'm curious if other people go by their LMP for dating, or the conception date if you know it? DH was working away so I know what day we conceived for sure. Going by LMP I would be 3w5d but going by conception I would be 4w1d. I know a few days difference doesn't really matter but I'm just curious

 

[Bevziibubble]

Hi and welcome back! Congratulations

 

[SCgirl]

If you know conception, use the conception date as exactly 2 weeks. Otherwise use LMP. (So you won’t even find out until at least 3.5-4w pregnant)

 

[DobbyForever]

Agreed. I'd go by conception. Your doctor may not though. I know conception with DS because I was tracking O, but they didn't want to hear it haha. Also, just keep in mind the BD day isn't always necessarily conception day. Sperm can live in the body for a couple of days waiting for the egg, so really anywhere in that timeframe could be a viable conception date.

No matter when the day, congrats!!!!!

 

[Tonka106]

Yeah, I figure my doctor will go by my LMP too. We BD'd on CD 11 so it's somewhere around there for sure. I have a slightly shorter cycle too so today is CD26 and would have been AF day. I'm gonna go with that CD11 as the 2 week mark, for myself anyway haha.

 

[LALSmith]

Ultimately any dates you have in mind will probably be scrapped at the dating scan anyway. Mine have always moved forward from LMP when I have the scan but all babies have still been late haha. I was always pleased when they jumped forward a few days to a week as i thought it meant meeting baby sooner but not for me. DD1 & DS2 were 7days late and DD3 was 13 days late lol

 

[Rags]

I had AI so knew exactly my date, as pp said the midwife ignored that and went from lmp - ds was born pretty exactly to my insemination date.

 

[Twag]

I knew the conception dates of both of mine and worked out their EDD but Dr's go by LMP and then at dating scan they were both moved forward a week so they ended up being late by the official dates but they both pretty much arrived when I expected and calculated them by