Sciencey question about hormones and luteal phase

[VJONES1985]

Hello all. This is just a question I have often wondered, no real reason for my question but I know this board has lots of knowledgeable people ;-)

Am I right in thinking that after conception, a big progesterone will prevent menstruation from occurring? If so, why does it matter how long someone's luteal phase is? If the luteal phase is too short, why does the rise in progesterone not prevent menstruation? I sometimes have short luteal phases of around 8 days, so if I conceived and had not implanted by 8dpo, would implantation definitely not happen?

As mentioned, this isn't something in fretting about (at the moment), just something I've never fully understood. Thanks.

There are two stages:

fertilisation and implantation

With fertilisation, the fertilised egg (blastocyst) is just drifting through the Fallopian tube. It needs to implant in the endometrium in order to stick and grow, otherwise it just gets flushed out when your period begins.

It’s only at implantation that you are pregnant, and it’s only then that your hcg and progesterone levels rise

But yes. Short luteal phases could mean there isn’t enough time for the blastocyst to implant.

Progesterone is made by the ovarian follicle, after the egg has been released. If it doesn’t get the signal in time to keep going in, it packs up shop and flushes out the old endometrium, meaning you can’t get and stay pregnant