If sperm only live an average of 48 hours why is EWCM four days before ovulation?

[Meelly]

Can anyone explain it?

They can live up to 5 days?

Yes they can, but that’s only quite a small proportion that actually live that long. The majority die within the first 24-48 hours.

I think 48 hours is outside of the body. X

You only need one sperm to survive, so that's why!

It’s to give the best possible chance of pregnancy in any given month. EWCM is the best environment for sperm to live and move in, so if there’s lots of it there then more of the c. 200 million-500 million sperm in the average ejaculation will survive the 4 days to ovulation. By that time they’ll likely be in the right place (fallopian tubes), waiting for the egg to pop. Ok, better still if sex happens 2dpo as more of them will still be alive. But if there’s no EWCM 4dpo then any sex that happens then has a near zero chance of resulting in a pregnancy. If there is EWCM the chances are not as good as a day or two later, but it could still happen. It’s just evolution playing the odds.

There's no disadvantage to having a longer period of EWCM, but there would be a disadvantage to having less days with it.

In which case I don’t understand why EWCM isn’t in the two days immediately prior to ovulation?!

Do you mean you don’t understand why it gets thinner/more watery? Hmm, maybe that makes it easier for the sperm to swim through. So, they might not live as long in it but that doesn’t matter because the egg has a short shelf life anyway, so sperm longevity is less important than sperm speed?