IVF, cars, eggs, sperm , batteries and engines

1. Why an IVF Cycle is just like driving a Car
Doing an IVF Cycle is just like driving a car.
When we drive a car, our aim is to use the vehicle to reach our
destination. Similarly, when a couple undergo an IVF Cycle, their aim
is to get good embryos, so they can have a baby.
A car is powered by 2 main parts - the Battery and the Engine. In
baby-making, the major components are the Sperm and the Egg.
What does the Battery do in a Car
The Battery's job is to kick-start the engine, so it gets ignited into
action. This is just what the sperm do to the egg !

2. The sperm's Job is to fertilise the egg, and when it does so , it
activates it, so that the embryo which is formed can continue to divide
and grow.
What does the Engine do in the Car

3. The engine is powered by fuel, and provides the energy need to keep
the car going. This is role of the egg in reproduction too .
The mitochondria in the cytoplasm of the eggs are the powerhouse of
the cell, which provide the energy which drives embryo cleavage.
This means that in most cases, the role of the sperm is limited to
activating the egg. Once it has done so, it doesn't have much of a role
to play in embryo cleavage. Thus, once the battery has kick started
the engine, it remains a silent spectator during the rest of the journey.
What if the battery doesn't work properly
When the battery doesn't work, the engine won't start and the car
remains stuck ! Similarly, if the sperm don't work well, they won't be
able to activate the egg. Some sperm are dysfunctional, and cannot
activate the egg on their own. These sperm need some help, and this
is provided by doing ICSI. For example, in patients with
globozoospermia, the acrosome ( cap on the head of the sperm) is
missing.
Such patients cannot conceive naturally. They need to undergo ICSI
cycle, wherein we can assist Oocyte Activation (AOA) using 4-bromo
calcium ionophore.

4. What happens when the Engine of a Car doesn't work
properly ?
If the embryo fails to divide properly ( there's lots of fragmentation
during cleavage, and the embryo is poor quality, or if it arrests , this
suggests the problem is with the mitochondria in the egg cytoplasm.
Sadly, there is no way of testing their function, except by actually
doing IVF, and seeing how the embryos grow in vitro.
This is usually seen in patients who have poor ovarian reserve -
typically, older women and those with low AMH values .
Sometimes, we can improve egg quality by tweaking the
superovulation protocol, but often this remains the major hurdle to
achieving a pregnancy in these women.