First step: ovulation
Ovulation occurs when an egg from a woman's ovaries is caught by the ends of the
fallopian tube. Knowing exactly when you're ovulating is important because eggs
are only viable for 12 to 24 hours after ovulation. Once a released egg has expired
without meeting its sperm mate, the optimum conception window closes until the next
The race is on
Ejaculation sends millions of sperm into the vaginal canal for a 30 minute journey
to reach the fallopian tubes. It takes another 15 to 20 minutes for the sperm to
find the egg and only a few dozen will make it – the rest get trapped, lost or die
along the way. For the lucky few who make it, they must fight to fertilise it. Once
a sperm breaks through, a protective shell prevents any others getting into the
Within 30 hours of fertilisation, the egg divides into two cells and, within four
to five days, this will have reached a sixty-cell stage. All the time, the egg,
called a zygote, is making its way through the fallopian tube towards the womb.
The miracle of life
Now called a blastocyst – and made up of hundreds of little cells – this soon-to-be-baby
is then ready to be adhered to the uterine wall, known as implantation. This event
will start taking place towards the end of the week and within two weeks is complete.
This is about the time when a woman would usually expect her period to arrive, but
instead discovers she's pregnant.