A lot of people expect this part to be straightforward.

Egg and sperm meet.
Fertilisation happens.

So the assumption becomes:

“Once fertilised… it should keep growing.”

But then updates come in.

Some embryos stop.
Some don’t reach the next stage.

And the numbers quietly drop.

This is where expectation shifts.

Fertilisation is only the first step.

After that, the embryo still needs to keep developing over several days.

From a single cell
to multiple cells
to a more stable stage.

Not all embryos can continue that process.

Even if fertilisation looked successful at the start.

Then why does it stop?

Because early development depends on many small things working together.

Some of these are visible in the lab.

Many are not.

So an embryo stopping doesn’t always mean something was done wrong.

It often means that embryo
wasn’t able to continue developing further.

This is why IVF numbers tend to decrease step by step.

From eggs
to fertilised eggs
to embryos that keep growing

And that drop, although common,
is something many people don’t expect at the beginning.