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earliest possible DPO for positive test
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Anonymous
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I am trying to figure out when I ovulated and one piece of the puzzle is the day I got a BFP. Working back from the BFP, what is the shortest number of days past ovulation that a home test would show?
I don't think I'm being clear. Let's say your answer is 10 DPO, then you would be telling me that if I got a positive on the 30th, I had to have ovulated on the 20th or earlier. The home tests all count from the other direction, days until your period is due, but I have a later ovulation and 10-11 day lutueal phase so that isn't helpful. |
Anonymous
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That is a tricky question I don't think can be answered. Everyone ovulates differently. The time for conception would be the same, but then implantation is 6-10 days after ovulation. So, you could theoretically get a positive 10 days past ovulation or it really could be later.
Why are you trying to figure this out? Generally they decide your due date from the date of your last menstual period. just curious. |
Anonymous
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Thanks, PP. I am trying to find out ovulation/conception so I can know how far along I am and the due date. My practice prefers ovulation over the date of your last menstrual period because the difference can be a week or more, as it would be for me. The LMP date works if you have a 28 day cycle and ovulate on day 14. I ovulate (or used to) on day 18 or later.
I don't know when I ovulated this cycle or even the real date of the LMP because I just want off an IUD. I never really had bleeding on the IUD so the few days I spotted don't necessarily count as LMP. And my temperatures were all over the map so I don't know what day I ovulated. It's been two years since I've been able to chart (pregnancy plus birth control), I am older now, and this is the first cycle post-birth control, so I don't really think I can assume this cycle followed the two-year-old pattern. My bottom line question is, if you get a positive test on day T, you know you didn't ovulate the day before, day T-1. You know you didn't ovulated two days before, T-2. What is the earliest you could have ovulated? Could you have ovulated 6 days earlier, T-6, or would the test not show a positive then? I am pretty sure the tests can show by 10 DPO. |
Anonymous
| I think the best way to tell your due date would be early ultrasound - if you don't have regular cycles, anything else is just a guess. I have irregular cycles and got pregnant on a natural cycle. My due date by LMP was 7 days earlier than my actual due date based on gestational age by early ultrasound. |
Anonymous
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I agree that ultrasound is the final way to determine but we won't know that for weeks. I have chemical pregnancy reasons for wanting to know the timing before then.
It seems like this should be such a simple question. The makers of home pregnancy tests treat us like idiots. Their literature and online information assumes everyone ovulates on day 14 and has a 28 day cycle. |
Anonymous
This is the 8:19 poster again  This website shows average hcG levels for viable (heartbeat detected) singleton pregancies by DPO. As you can see, the ranges are so huge that you probably won't get a whole lot of insight from this chart either. If you figure that most home pregnancy tests can detect hcG values of around 25, most people woulnd't get a positive hpt until 11-12 DPO, but the hcG ranges are so huge, that you could get a positive hpt earlier than 10 DPO and as late as 20 DPO.
http://www.betabase.info/showBasicChart.php?type=Single |
Anonymous
Thank you! This is extremely helpful to see, even though you are right the ranges are so huge it doesn't tell me all that much. It does make me fear for twins. |