And the answer is..........it all depends. Suck answer huh? Okay but here's why:
The embryo begins implanting anywhere from 4 - 12 days and it takes about 4 - 7 days to finish implanting. Although the conceptus starts secreting progesterone and estrogen at fertilization, it is the placenta itself that secretes the hCG. The placenta has to be attached (implanted) and vascular communication established before hCG from the placenta can be released into the mother's bloodstream. hCG is the hormone you're looking for when testing for pregnancy.
This is why some people can get a + HPT at 8 DPO and some not until 19 or so DPO, it depends on when implantation began and when it was complete.
I believe the statistics show that most implantation begins at 8 DPO and completes in about 6 days, which is why an HPT is 95% accurate at 14-15 DPO. This does not mean it is impossible to get a BFP after 15 DPO just more unlikely.
GENERALLY SPEAKING these are the most common beta levels ranges in pregnancy. Of course the level is not nearly as important as whether or not it is doubling every 2-3 days.
HCG level for single baby (mIU/ml or IU/L)
Week 3,
0 to 5
Week 4,
5 to 426
Week 5,
18 to 7340
Week 6,
1,080 to 56,500
Weeks 7 to 8,
7,650 to 229,000
Weeks 9 to 12,
25,700 to 288,000
Weeks 13 to 16,
13,300 to 254,000
Weeks 17 to 24,
4,060 to 165,400
Weeks 25 to birth of baby,
3,640 to 117,000
4 to 6 weeks after birth,
Less than 5
