hCG baseline, which matters?

[WantsALittle1]

The widespread view seems to be that hCG starts doubling every 48h from whatever the mother's pre-pregnancy baseline hCG is. That doesn't make sense to me, though. Isn't it the embryo's baseline hCG at implantation that matters, not the mother's?

With my son, at 12 DPO, my serum hCG was 44. My baseline (non-pregnant) hCG, as measured multiple times when not pregnant, is < 1 miU/mL. So that means, according to the idea above, I had already doubled from my baseline before my son had even implanted. How is that possible?

If my baseline is used, here is how the doubling would go. At 12 DPO my hCG should have been 8, right?

6 DPO: 1 miU/mL
8 DPO: 2 miU/mL
10 DPO: 4 miU/mL
12 DPO: 8 miU/mL
14 DPO: 16 miU/mL
16 DPO: 32 miU/mL
18 DPO: 64 miU/mL


It seems more likely to me that when my son implanted at 6 DPO, his baseline was already 5-6 miU/mL, and so things started doubling from his baseline, not from mine:

6 DPO: 5 miU/mL
8 DPO: 10 miU/mL
10 DPO: 20 miU/mL
12 DPO: 40 miU/mL

 

[sdc010905]

Never thought of this but interested to see response. What your saying makes so much sense and ive never understood why iv had 2 pregnancies that ended in mc with slow-rising hcg and then 2 more that went full-term with great numbers....could explain it but i never know for sure why mcs happen i suppose..

 

[lisap2008]

Human chorionic gonadotrophin is a hormone produced by the cells that surround the growing human embryo; these cells will eventually go on to form the placenta , levels can vary much from one pregnancy to another ,48 hours doubling time is a sign its a healthy pregnancy but numbers can double much faster then 48 hours or sometimes its slower and more of a 72 hour doubling time. Its important not to stress too much over HCG numbers.