When does the placenta take over?

Question

When I Google it, I get contradicting results. Anyone know?

Answer

From my research, between 7-9 weeks the luteal-placenta shift takes place. This is when a lot of women have spotting or start feeling like they’re ‘not pregnant.’

Answer

My OB told me around 10 weeks. I had to take progesterone and was told I could stop at that time since the placenta takes over.

Answer

It can begin to start functioning around eight nine weeks but it's not solely functioning. It begins solely functioning and taking over fully around 12 weeks.

Answer

My OB said late into the first trimester.