A lot of people assume IVF solves this part.

Egg is there.
Sperm is there.

So it feels like:

“Fertilisation should happen, right?”

But sometimes, it doesn’t.

No embryos form.
Or very few.

And that can feel unexpected.

Because IVF is often seen as making fertilisation “guaranteed”.

But it’s not.

Even in IVF, fertilisation is still a biological interaction.

It’s not just about putting egg and sperm together.

They still need to respond to each other in the right way.

Sometimes that interaction doesn’t happen as expected.

Even when both look normal.

Then what about ICSI?

If sperm is injected directly, shouldn’t that solve it?

ICSI can help bypass part of the process.

But even then, fertilisation is not 100%.

Because after injection, the egg still needs to activate and begin developing.

And that step doesn’t always happen.

So fertilisation failure isn’t as rare as people think.

It’s just one of those parts of IVF
that still depends on things we can’t fully control.