sarah1989

Wasn't really asking if my pregnancy was viable or not, as I have had a . I was just asking in general

poppy

I would say that to have a viable pregnancy, the doctor should pick it up on a blood test. For urine tests, I am not sure - early on it may not show up - but you'd think that after a few weeks the hcg should have risen enough. However, there does seem to have been people who have not got BFPs on urine tests but have been pregnant.

moxie08

NHS Evidence suggests that when presented with a possible pregnancy, one should never rely solely on a urine test for a diagnosis. There are few valid and reliable indicators of pregnancy -- ultrasound being one of them.

The reasons HCG tests are not completely reliable: (1) HCG as a molecule shares many of its bits with LH (hence using OPKs sometimes gives a positive) and (2) there are different kinds of HCG molecules.

The reasons urine tests are even less reliable: (1) HCG gets chopped up unevenly into various bits before it gets excreted, (2) urine may be diluted, cloudy, or all other sorts of polluted, (3) all of the reasons HCG tests in general are not completely reliable.

Different pregnancy sticks test for different combinations/parts of the HCG molecule. They also have different sensitivities. If you suspect you are pregnant, you are perfectly right to request a blood test, as there is medical literature to support your request.

poppy

That's really interesting - I didn't know any of this.

MsLesley

I cant say for sure..but i think when she said "you"...she meant in general..know what i mean? I talk like this all the time...i will say "you" meaning in general terms and not actually directed to the person im speaking to...people hate when i do this tho..it confuses them

Congrats again on your bfp btw

sarah1989

Lol, now I do, after reading it over again sorry!!!

mandy81

I know a girl who never got A BFP, then found out she was 3 months pregnant. xx

moxie08

It's a concern in the medical field that there is a such a high reliance on HPT when a 'negative' is interpreted as 'not pregnant' ... and further concern when research shows that outside a laboratory the reliability of these tests drops from 99% to 50-70%. If you haven't gotten your period and you suspect pregnancy, you have every right to request a blood test from your GP in the NHS. My own GP offered the blood test if I didn't get a and my period was a week late.

sparkle83

very interesting... but I'm now curious as a step on from this, can you have bfps in previous pregnancies, and then never get one in a subsequent pregnancy?

moxie08

Probably very unlikely -- but I wouldn't rule anything out completely. There may be an environmental reason why a women processes her hCG molecules differently and/or her urine is a degraded quality. But it is very unlikely.