How can you get a BFN when your pregnant?

Have had a lot of replies this week to my posts about AF being late but getting BFNs that have said it isn't over until AF arrives (I'm now three days late but had three BFNs), and I notice some people have not had BFP until one or two weeks after AF was due. So I just wondered why this is. I know that pregnancy tests measure the pregnancy hormone, but I thought if you were pregnant then you would produce this hormone from the day AF is due so why would you not get a BFP?

Hope this makes sense - just feeling a bit confused.


  • hi,
    i know what you mean about it not showing up but couldn't tell you why. when i did a test after af being 4 days late i got a BFN but after 9 days i got a BFP.
    i know the wait must be awful but just keep positive.
  • I think you start producing it from the day you conceive but it is in such small amounts for quite a long time that a preg test can't pick it up. I don't know why it vaires from person to person, I guess the same reason why we all get different symptoms, that all of our bodies are different.
    Hpt are very accurate when positive but years ago they didn't exist and people had to wait months to find out if they were pg as the hormone levels are low for quite a while.
    Hope you get your BFP soon.
  • You are testing for HCG which is only present once implantation has occured. So you may start producing it 7-10 days DPO if you have been successful and it increases daily. You you know how many DPO you are?

    PMA coming your way. x
  • It is probably when you have ovulated later in your cycle than you thought, so your period isn't actually due. The other explanation is that our bodies are complete mysteries to us...Ho hum.
  • I would imagine that if it is quite diluted in your urine then that can make the difference between a BFN and a BFP in the early days. Fingers crossed and babydust for you x
  • Thanks girls - it's all so confusing isn't it? I think you're right emmj - we're probably a bit too impatient about finding out asap in this day and age. I think I'm around 17 dpo but not certain this month as didn't use my ov sticks cos was on holiday but definitely did lots of bd'ing around ov time. I have been ov'ing and getting af at exactly the expected time for the last six months so am a bit flumoxed (sp!) because things are messed up!

    I wonder if boys have a similar forum where they talk about the amount of sperm they have produced and it's consistency, etc :lol:
  • I had 5 BFNs last month and my period was 5 days overdue. I think that in very rare cases some women don't produce enough hormones to register on a test (even at the doctors and even with a blood test) but it is very rare. Periods can come late for a variety of reasons and it being late is not always a sign of pregnancy.

    when did you come off the pill and have your periods always been regular? Do you know when you are ovulating (Are you using OPK?) and did you know this month?
  • I've been off the pill since October last year and ttc properly since February. Since October my periods have been 27 days and I have been using ovulation sticks (is this OPK??) since February and am ov'ing on day13. Didn't use sticks this month as was on holiday but definitely bd'd plenty around this time.

    I guess it's maybe just a wonky month for me!

  • how weird, apart from your cycle length (Mine is 24) you are almost identical to me image I started trying in Oct. I have had 2 months where I was really late with my period and both times I was hoping I was pregnant despite the BFNs. I still don't really know why I was so late and I was so disappointed both times when my period came. One month I think it's possible I didn't ovulate.

    yes OPK are ovulation thingies. I'm using a clearblue fertility monitor so I know when I am ovulating but this month I have ovulated 6 days earlier than usual which I think is weird as my period was six days late. Maybe my body is being a fool!!

    good luck!
  • blimey that is a bit of a weird cycle beanz. I would be 100% sure it was just a late af if I hadn't been cramping for the last week, and feeling like absolute poo aswell. Am not going to let it take over anymore though, and I know I'm lucky to usually have regular periods as there are others who are having a much harder time of it than me.

    Good luck to you too - will be looking out for your bfp!

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