Hook effect?

[britgirl82]

sykesmom -that's fascinating. Thank you so much.

Do you think the different isoforms could explain why some women don't get positive OPKs despite getting positive HPTs (and being pregnant)? There is a theory that OPKs can be used as HPTs since HPT is like 'LH plus something' so a positive OPK shows pregnancy, but this doesn't seem to work for everyone.

And step away from the tests!! Your tests will still show positive for a while should you miscarry so they tell you very little at this stage.

 

[skyesmom]

OPKs test for a different hormone, the luteinizing hormone which rises just shortly before the ovulation and drops down afterwards if the fertilization doesn't occur... but if you do get pregnant and the egg is fertilized, the luteinizing hormone stays up and sustains the so called corpus luteum in the ovaries which otherwise would collapse (an active corpus luteum is needed only in case of pregnancy, as its function is to produce progesterone until the placenta takes over).

so if you are pregnant, the OPKs do "detect" pregnancy as they detect the high levels of luteinizing hormone, that wouldn't have been present if you weren't pregnant. (in fact,if you're not, the LH levels drop immediately and you don't pick it up anymore at 1, 2, 3 DPO and so on).

but OPKs don't detect the HCG. the HPTs detect the so called "pregnancy hormone" the HCG, so they're different from the OPKs and are not "the OPKs plus something". they detect a whole different hormone, that's present only a few days after implantation.

why some women keep getting negative OPKs while being pregnant has certainly to do with the isoforms and also a hook effect as the LH levels raise during pregnancy and may be too much for a test strip to read.

it's funny how the body changes immediately after the egg is fertilized, days before the HCG is set into production.. when i hear people saying you can't have any pregnancy symptoms before implantation etc etc etc... and that your body doesn't know it's pregnant before HCG is produced... i'd make them re-think... we live inside insane biochemical machines! HCG is the most famous pregnancy hormone but definitely not the only one to be affected or changed!

 

[RandaPanda]

hey randapanda! so happy to hear about your scan! yay!!

our's went great too...i was 6 weeks, 6 days - but baby was measuring 7 weeks, 2 days...heartbeat of 144...all looked perfect!! YAY!!

Awesome news!!

 

[skyesmom]

Randapanda and Anniecrock: SO SO happy for you both!!!