When do hcg levels show in blood?

[Ailsa84]

Long time lurker here but I wasn't too sure where to put this post.

I have a query about Hcg levels and when they can be detected in blood.

If I ovulated on or around the 1st July and the egg was fertilized would HCG show up in a blood test done on Monday 8th July?

I don't know the exact answer but I think you have to wait two days til after implantation for hcg to start being released.
This happens on average 6-12 days after ovulation, so it's possible but also if it's negative it could've just not implanted yet

Did your hCG who requested the blood tests specifically ask for beta hCG to be checked? It’s quite unusual for it to be checked so early unless as part of fertility treatment.

I am 28 weeks into an ivf pregnancy and had a blood test done 7 days post 5 day embryo transfer (so 12 days after eggs were fertilised) specifically to see if the cycle had been successful. I was warned that, even at that point, levels may be low enough that the result could come back negative but only because it was so soon.

I have read a few things about progression and measuring hCG levels and found that, it can take 12-36 hours from ovulation to fertilisation
3-5 days from fertilisation to implantation and
4-6 days from implantation to detectable levels of hCG so in total it can take 7-12 days from confirmed ovulation to detectable levels of hCG. Also, remember, that levels are set in a range not just a fixed point so you may be producing low levels that would not be classed as positive but you are actually pregnant - which is why they recommend a series of blood tests 48-72 hours apart to detect rising levels.

This is why, when you have ivf, they recommend blood hCG levels are done 12 days post transfer and urine test 14 days post transfer - to allow levels to build up sufficiently.

I had bloods taken to check for remaining hcg after a miscarriage but just wondered if I was really early on (like the dates above) with new pregnancy then the hcg may not be produced yet. Thanks for you comments, really helpful :)

Hi Alisa84! I took my beta hcg test about 11 days after my embryo transfer. Then i had to take another test two days after to see if the number doubled. Hope this helps!

did you get ivf too?

@Ailsa84, at those dates, I would say if there is any hCG detected then it’s more likely to be residual from your miscarriage. If levels were still quite high for length of time post miscarriage, then I would ask for a repeat blood test to see if it is rising or dropping.