What's more accurate to calculate # of weeks pregnant?

JulesF84 · July 2011

I put in my EDD to get my ticker calculated and I also tried putting in my 1st day of my last period. It's about a week difference. If I go by the 1st day of last period, I'm 5 weeks, but if I just put in my EDD, I'm almost 5 weeks. What is more accurate? I'm not seeing my doctor until the 29th.

mjmonkeylove · July 2011

Most Dr.'s will go by first day of LMP unless you O late which a U/S will be able to confirm for you

speckledfrog · July 2011

At my first appointment they gave me an EDD based on the first day of my last period. I go in for a sonogram at the end of the month and I'm interested in what the doctors says at that point.

greeneyed_bride · July 2011

JulesF84:

I put in my EDD to get my ticker calculated and I also tried putting in my 1st day of my last period. It's about a week difference. If I go by the 1st day of last period, I'm 5 weeks, but if I just put in my EDD, I'm almost 5 weeks. What is more accurate? I'm not seeing my doctor until the 29th.

I'm confused. If you haven't seen your doctor yet, how do you have an EDD that's based on anything other than your last period? Unless you were charting and know exactly when you ovulated, the first day of your last period is really the only way you can estimate a due date until you've seen your doctor.

mjmonkeylove · July 2011

greeneyed_bride:
JulesF84:

I put in my EDD to get my ticker calculated and I also tried putting in my 1st day of my last period. It's about a week difference. If I go by the 1st day of last period, I'm 5 weeks, but if I just put in my EDD, I'm almost 5 weeks. What is more accurate? I'm not seeing my doctor until the 29th.

I'm confused. If you haven't seen your doctor yet, how do you have an EDD that's based on anything other than your last period? Unless you were charting and know exactly when you ovulated, the first day of your last period is really the only way you can estimate a due date until you've seen your doctor.

for now yes

RN4Babies81 · July 2011

If I go by my LMP I am a week ahead of where I actually am and I know this because I was cycle monitoring and I ovulated on day 21, not day 14. I know the exact day I ovulated so my EDD is actually a week later than what my LMP would say.

greeneyed_bride · July 2011

RN4Babies81:
If I go by my LMP I am a week ahead of where I actually am and I know this because I was cycle monitoring and I ovulated on day 21, not day 14. I know the exact day I ovulated so my EDD is actually a week later than what my LMP would say.

Yeah, that makes sense. I know exactly when I ovulated, so I know that my EDD is actually two days later than what it would be based on my LMP. OP didn't mention that she charts, so I was confused as to how she could have an EDD based on anything other than her LMP.

JulesF84 · July 2011

Yes, I was charting, so I know when I ovulated. My chart is linked in my sig.

greeneyed_bride · July 2011

JulesF84:

Yes, I was charting, so I know when I ovulated. My chart is linked in my sig.

Wow, I'm out of it today! Ok, since you know when you ovulated, your EDD based on Fertility Friend is going to be more accurate than the first day of your last period, because an EDD based on your LMP assumes that you ovulated on CD14. Since FF knows you ovulated later, the EDD it gave you is more accurate.

Sorry for my complete lack of observational skills today!!

cinderella4282 · July 2011

I based my ticker on the the EDD that my doctor gave me based on my first u/s. I wanted to be accurate with what I hear from the doctor.

I would suggest you base your ticker on the later date and then if you need to adjust it up you always can.

avalovesart · July 2011

And of course the baby's going to come when he/she's ready anyhow, despite what the EDD says

SweetBaby2004 · July 2011

RN4Babies81:
If I go by my LMP I am a week ahead of where I actually am and I know this because I was cycle monitoring and I ovulated on day 21, not day 14. I know the exact day I ovulated so my EDD is actually a week later than what my LMP would say.

I always go by what date I get based on ovulation, temping, etc, since the dr will go by LMP. Since I always ovulate on CD 21 or 22, I know I am always a week behind a "normal" calculation. Usually by the first u/s, they discover that in fact, I am a week behind and adjust my due date anyway.

sunnyday016 · July 2011

Go by your ovulation date if you know it.

ghdst1 · July 2011

From what I have read on here from the other ladies it really depends on your doctor. Some Drs will go by LMP and really don't want to know about your charting. My Dr was very open to talking to me about my charting and the fact that I knew I ovulated on CD 20 which moved my due date a week later than if it was based on my LMP.

I would talk to your dr at your appointment and when they ask about your LMP you can also mention you know when you ovulated. If for some reason they still base your DD on your LMP it can always change once you have a dating u/s.

diana.filipi · July 2011

avalovesart:
And of course the baby's going to come when he/she's ready anyhow, despite what the EDD says

In the end this is the hard truth :-)

annapolischick · July 2011

I know my body well enough to know when i ovulated but I also know that my periods have been between 35-40 days... so the typical 28 day cycle they normally calculate is incorrect for me. I told my OB that i have a 35 day cycle and they based it off that which would put me right where i think i should be.