[CandaceDianne]

how do you calculate how far along you are? From the start of your last period?

[~April04~]

If you don't know your conception date (which is usually when you ovulated) - then you go by your LMP.

Docs usually go by your LMP unless you did something like IUI or IVF.

[Etph007]

Not a stupid question!! Your dr should be able to give you a for sure date with a dating u/s... but usually they are either based on your LMP or conception date. Here are a few calculators that may help:

Pregnancy Due Date Calculator | Tools | BabyCenter
Due Date Calculator
Due Date Calculator - Pregnancy Weeks Calculator

[Lauren S]

Doctors usually always go by your last period. I ovulate late and knew exactly which day I O'd on, so I counted back 14 days and told them that was when my last period was.

No, I didn't tell the truth. But I had to have a c-section at 38 weeks, and if I had let them go by my LMP then he would have been even earlier and even smaller. Worth a little white lie to me!

[CandaceDianne]

Ok because I had a late ovulation date as well....I have my period of August 19th, O'd on September 9th (Cycle Day 22) and got my BFP on CD 33 (11DPO).
Ok I used one with my conception date and then one based off of my estimate LMP (only have one full cycle off of bcp and it was 34 days long)....the one based off of my conception date is June 2nd and the one based off of my LMP is June 1st....close enough for me!

[Christine-MA]

I did what Lauren did even though it was only a few days different. Even still, I had an early ultrasound (because of two previous m/c) and they dated from that. I know from ovulation I'm "really" due 12/28 but the first u/s dated me 12/26.

[stlgirl]

mine was almost a WEEK apart, so I went by O date not LMP. my first ultrasound confirmed that I was right on the money