Human chorionic gonadotropin (hCG) begins to rise shortly after implantation of the embryo into the uterine lining. Implantation typically occurs about 6 to 12 days after ovulation. hCG production starts approximately 1 to 2 days after implantation and then doubles roughly every 48 hours during early pregnancy
. Detectable levels of hCG in blood or urine usually take about 6 to 12 days post-implantation to reach a threshold that can be measured by pregnancy tests. This is why the common recommendation is to wait about two weeks after ovulation or embryo transfer before testing for pregnancy to avoid false negatives
. In summary:
- Implantation occurs roughly 6-12 days after ovulation.
- hCG production starts 1-2 days after implantation.
- hCG levels double approximately every 48 hours in early pregnancy.
- Detectable hCG levels for pregnancy tests appear about 6-12 days after implantation, often coinciding with the missed period.
This timeline explains the typical "two-week wait" after ovulation or embryo transfer before a pregnancy test can reliably detect hCG
