Due date more accurate from date of conception or first day of last period??

gubeedal · Mar 27th, 2012, 12:21 PM

I ovulated early this month. I know my date of conception was 2/21/12. The first date of my last cycle was 2/11/12. According to my last cycle, I am due November 18. According to my conception date, I am due November 13.

Which date should I go by????

Kare2012 · Mar 27th, 2012, 12:24 PM

They go by LMP because a lot of women don't know when they ovulated but if you know for sure when you did then I'd go by that!

taylorxx · Mar 27th, 2012, 13:25 PM

Conception date is the most accurate because most women don't always ovulate on CD14. If it's more than a week off, they go by conception date as it is the most accurate. However, if it's pretty close, they go by LMP. If you go by LMP, keep your conception due date in mind in case you measure behind/ahead, etc. If I were you I'd go by conception date since you'd be further along xx

linzay55 · Mar 27th, 2012, 13:51 PM

Conception date is most accurate, for this pregnancy I did ovulate on cd 14 so I just went with lmp but if it was off I would go with ovulation date.

minties · Mar 27th, 2012, 14:33 PM

Gets even more confusing when you have a scan and that comes up with a 3rd date!

My LMP was December 31st, so no way I am going by that haha! My conception date is the 17th of Feb, but according to the scan I had, it was Feb 20th (4 days after I last had sex, and 5 days after I had any EWCM and OV pains).

So by LMP I'm 15.5 weeks, by MY dates I'm 7w5d (also by the sac size at my 6 week scan that is correct), then according to the tech at my 7w3d scan I was 7w at the most. Confusing. The midwives will go by the second scan. They don't trust women to know their own cycles.

2016 · Mar 27th, 2012, 14:35 PM

If you are very sure when you ovd (like by OPKs and temping), then I would use that. You may find as I did that a doctor won't want to hear that you could actually know when you ovulated. To get around this I normally adjust my LMP date and tell them a date that would mean I ovd on CD14....so in your case you would say your LMP was 6th Feb. I can't do that this time cos they know my dates due to having fertility bloods done on CD2.

I only ovd on CD17 though so am going by LMP to save a petty argument over 3 days.

Oddly enough with DS my EDD by LMP was 28th December, by ov 31st December. At 12 weeks they changed my date after a scan to 24th December so a whole week earlier than I knew for certain the date should be. And STILL he measured 1-2 weeks ahead this new date the whole pregnancy. He then arrived on 25th November, 6lbs 6oz so was clearly in a hurry!

Nikki Leigh · Mar 27th, 2012, 19:19 PM

I use my conception date. I used my LMP date to book my initial scan, and then when we did the scan, the OB dated closer to my conception date and uses that as my EDD (off by two days).

Chrisy77 · May 2nd, 2012, 03:32 AM

going from my lmp my edd is 13th October but I've had 3 scans all saying 16th October so my conception date is about 21st January. does that sound accurate?

gubeedal · May 3rd, 2012, 10:30 AM

Quote:

Originally Posted by Chrisy77

going from my lmp my edd is 13th October but I've had 3 scans all saying 16th October so my conception date is about 21st January. does that sound accurate?

Yup. I posted this a long time ago actually. I ended up having a scan to determine my due date, because when I got examined, my doc agreed that I was likely further along that what my LMP was. After my scan, they pushed up my date. My original due date as 11/18, and now its officially 11/12

Almost a full week earlier.

ashleyann · May 3rd, 2012, 10:41 AM

The doctor's will give you a due date and I would go by that. They will monitor along the way to make sure baby is measuring where hes supposed to and may adjust accordingly. They went by my LMP for me even tho I was temping and knew that I ovulated later than day 14. (More like CD 20) Every ultrasound I was right on where I should be according to the LMP tho and now measuring even a little farther along so I guess they were right.

Mar 27th, 2012, 12:21 PM	#1
gubeedal Pregnant (Expecting) Active BnB Member Join Date: Mar 2012 Location: chicago,il Posts: 190	Due date more accurate from date of conception or first day of last period?? I ovulated early this month. I know my date of conception was 2/21/12. The first date of my last cycle was 2/11/12. According to my last cycle, I am due November 18. According to my conception date, I am due November 13. Which date should I go by????

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Mar 27th, 2012, 12:24 PM	#2
Kare2012 Pregnant (Expecting) Active BnB Member Join Date: Jan 2012 Posts: 200	They go by LMP because a lot of women don't know when they ovulated but if you know for sure when you did then I'd go by that!

Status: Offline

Mar 27th, 2012, 13:25 PM	#3
taylorxx Pregnant (Expecting) BnB Addict Join Date: Feb 2011 Location: US Posts: 5,312	Conception date is the most accurate because most women don't always ovulate on CD14. If it's more than a week off, they go by conception date as it is the most accurate. However, if it's pretty close, they go by LMP. If you go by LMP, keep your conception due date in mind in case you measure behind/ahead, etc. If I were you I'd go by conception date since you'd be further along xx

Status: Offline

Mar 27th, 2012, 13:51 PM	#4
linzay55 Mum (Mom) Active BnB Member Join Date: Sep 2011 Posts: 304	Conception date is most accurate, for this pregnancy I did ovulate on cd 14 so I just went with lmp but if it was off I would go with ovulation date.

Status: Offline

Mar 27th, 2012, 14:33 PM	#5
minties Mum (Mom) BnB Addict Join Date: Nov 2009 Location: New Zealand Posts: 6,163	Gets even more confusing when you have a scan and that comes up with a 3rd date! My LMP was December 31st, so no way I am going by that haha! My conception date is the 17th of Feb, but according to the scan I had, it was Feb 20th (4 days after I last had sex, and 5 days after I had any EWCM and OV pains). So by LMP I'm 15.5 weeks, by MY dates I'm 7w5d (also by the sac size at my 6 week scan that is correct), then according to the tech at my 7w3d scan I was 7w at the most. Confusing. The midwives will go by the second scan. They don't trust women to know their own cycles.

Status: Offline

Mar 27th, 2012, 14:35 PM	#6
2016 Mum (Mom) BnB Addict Join Date: Aug 2009 Location: UK Posts: 9,469	If you are very sure when you ovd (like by OPKs and temping), then I would use that. You may find as I did that a doctor won't want to hear that you could actually know when you ovulated. To get around this I normally adjust my LMP date and tell them a date that would mean I ovd on CD14....so in your case you would say your LMP was 6th Feb. I can't do that this time cos they know my dates due to having fertility bloods done on CD2. I only ovd on CD17 though so am going by LMP to save a petty argument over 3 days. Oddly enough with DS my EDD by LMP was 28th December, by ov 31st December. At 12 weeks they changed my date after a scan to 24th December so a whole week earlier than I knew for certain the date should be. And STILL he measured 1-2 weeks ahead this new date the whole pregnancy. He then arrived on 25th November, 6lbs 6oz so was clearly in a hurry!

Status: Offline

Mar 27th, 2012, 19:19 PM	#7
Nikki Leigh Mum (Mom) Active BnB Member Join Date: Aug 2010 Location: California Posts: 234	I use my conception date. I used my LMP date to book my initial scan, and then when we did the scan, the OB dated closer to my conception date and uses that as my EDD (off by two days).

Status: Offline

May 2nd, 2012, 03:32 AM	#8
Chrisy77 Pregnant (Expecting) New BnB Member Join Date: May 2012 Posts: 7	going from my lmp my edd is 13th October but I've had 3 scans all saying 16th October so my conception date is about 21st January. does that sound accurate?

Status: Offline

May 3rd, 2012, 10:41 AM	#10
ashleyann Pregnant (Expecting) Active BnB Member Join Date: Oct 2011 Posts: 879	The doctor's will give you a due date and I would go by that. They will monitor along the way to make sure baby is measuring where hes supposed to and may adjust accordingly. They went by my LMP for me even tho I was temping and knew that I ovulated later than day 14. (More like CD 20) Every ultrasound I was right on where I should be according to the LMP tho and now measuring even a little farther along so I guess they were right.

Status: Offline

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