Statistics for HPT's

Discussion in 'Trying To Conceive' started by Zen_Jenn, Sep 2, 2009.

  1. Zen_Jenn

    Zen_Jenn Mother

    Joined:
    Aug 12, 2009
    Messages:
    960
    Likes Received:
    0
    Hi y'all,
    I've made it through my first 'active TTC' cycle, and have found the statistics a little baffling. Every time I took an HPT and saw a :bfn: I wondered what the probability of me actually being pregnant was. So, I thought I'd start this thread so we can discuss, not just here anecdotes about a friend's sister's cousin who . . .

    Anyway, to begin, here's what I found from FRER website:

    "In clinical research, FIRST RESPONSE® Early Result Pregnancy Test detected the hormone level in 69% of women four days before their expected period (which is five days sooner than the day of their missed period), in 83% of women three days before their expected period, in 93% of women two days before their expected period, in 93% of women one day before their expected period."

    Now, I would assume that it means of women who actually are pregnant at the time of the test, as opposed to determining a BFN when the woman is not pregnant. Also, the whole 'days before' thing is confusing. If I have a really long cycle (i.e. AF is expected at 20dpo), then 4 days before is 16dpo, and I would expect a BFP if I were pregnant, whereas if my cycle is short (AF expected at 14dpo), I may not expect to see a BFP at 4 days before (10dpo). Is this correct? Anyone have some insight?

    The First Response Rapid Result is "99% accurate at detecting typical pregnancy hormone levels. Note that hormone levels vary." It seems that it only finds 95% of actual pregnancies (i.e. 5% of pregnancies have hormone levels that are too low to be :bfp: at time of testing).

    Anyway, I like to have all the information so I can update my beliefs whenever I get a :bfn: . It would probably be easier just to wait until 2 days after expected AF, and not have to worry about the numbers ;) .

    - Jenn
     
  2. chubbin

    chubbin Proud mum of one

    Joined:
    Sep 1, 2009
    Messages:
    1,544
    Likes Received:
    0
    I dont have any insights, but I found your post interesting. I like the fact that you are prepared to interrogate the statistics. I tend to agree that if a person has a shorter or longer LP then they will not necessarily conform to these statistics. I can only assume that the stats are based on an 'average' 14 day LP.
    Sorry I couldnt really shed any further light on this :) xx
     
  3. XxXBubsXxX

    XxXBubsXxX 1 Littl'en but want 2!!!!

    Joined:
    Jul 31, 2009
    Messages:
    157
    Likes Received:
    0
    Ok.... I ovuolated on the 12th August and my period was due on the 26th August (periods nare on time to the min). I took a test on the 23rd Aug with a First resronse and it was a bfn, thats 3 days before my period. i then tested positive on the 25th Aug. It all depends on when the egg inplants and im guessing i implanted on the 23rd aug when i did the test so wouldnt hvae been much hcg, it all depends when the egg implants and considering it can be from 6-12 days after ovulation most people get a bfn at 10dpo and consider them selves out of the game!!1 It all just depends on when the eggy sticks!!! x
     
  4. BumpyCake

    BumpyCake Preggers with #1

    Joined:
    Jun 10, 2009
    Messages:
    1,421
    Likes Received:
    0
    Here's an interesting site I found. Click on 'Pregnancy Test Statistics'. Scroll down to find your brand and it will chart when bfps were recorded. Even an FRER has several faint +'s recorded at 20dpo.

    http://www.countdowntopregnancy.com/
     
  5. kmac625

    kmac625 Mom to baby Clara

    Joined:
    Aug 9, 2009
    Messages:
    5,312
    Likes Received:
    0
    Hey Jenn, thanks for the stats!

    Are you sure your lp is 20 days long? Do you temp to see when you ov? That seems awfully long seeing as the average is 14 days and most are 10-16 days. Usually if your temp stays up for 18 days that means you are pregnant (which would put AF late by a few days).
     
  6. Zen_Jenn

    Zen_Jenn Mother

    Joined:
    Aug 12, 2009
    Messages:
    960
    Likes Received:
    0
    Thanks for the link! That totally helps some of my anxiety (or it gives me false hope ;) ). At least I have a better idea of the numbers now.
     

Share This Page