Ok, so we’ve been taught about the birds and the bees, we’ve learnt that babies don’t come from the cabbage patch, we know that egg plus sperm equals baby, but what is actually happening within your body when conception occurs.
Women are born with around 1 million potential eggs which are called follicles. This number decreases to around 300,000 – 400,000 by the time menstruation commences at puberty. From then on, during each menstrual cycle, one dominant egg (or in rarer cases multiple eggs) is released from the ovary at ovulation to begin its journey down one of the fallopian tubes where tiny hair like cilia, sweep the egg towards the uterus. It is during this journey down the fallopian tubes where conception and fertilisation can occur if sperm are present.
During sexual intercourse, men release around 200 million sperm are released at a rate of up to 45km per hour! This rapid speed slows significantly to around 30cm per hour as they make their journey towards the egg. In the average male around 15 – 45 million of these will be healthy enough to fertilise an egg and only around 400 will survive after ejaculation. Of these 400 hundred surviving sperm, about 40 will be strong enough to reach the fallopian tube and the vicinity of the egg. These remaining 40 sperm then go through a process called capacitation, which is an explosion enabling the sperm to penetrate the outer layer of the egg. After this process only one, if any, sperm will remain to fertilise the egg and conception to occur.
When two become one
That one sperm lucky enough to reach the egg will then prevent any other sperm from entering by altering the surface of the egg. This is the moment when the 23 chromosomes from the egg and 23 chromosomes from the sperm merge to supply all the genetic material required to create another human being. Conception begins!
It is at this early stage of conception that your baby’s gender, physical characteristics, their personality traits and basically everything that will make them ‘them’ is set. Some people claim they can feel this occurring and may experience period pain like symptoms at the moment of conception, however for most people all these amazing transformations are taking place without us even knowing.
Once fertilisation and conception have occurred, this fertilised egg is now referred to as a zygote. Growth has already begun within the zygote as it makes its way towards the uterus. This conception process generally takes around 3 – 5 days.
Once in the uterus, the zygote continues to develop and grow until it becomes what’s known as a blastocyst. A blastocyst consists of an inner and an outer layer. The inner cluster of cells will go on to become the embryo and the outer layer will become the placenta and related tissue to support the development of your growing baby.
This blastocyst will then attach and implant into the wall of the uterus. Implantation will generally occur around 5 – 8 days after fertilisation and conception has occurred and the blastocyst will have completely imbedded itself into the uterine wall within 9 – 10 days. The embryo is now ready to form.
The inner and outer cells now begin to divide and grow, with the inner cells developing into the embryo and the outer cells becoming the placenta, which will provide nourishment to your baby during your entire pregnancy. These placental cells will continue to develop further to form a protective outer layer of membranes known as the chironic sac and an inner layer of membranes called the amniotic sac. These sacs will encase and protect the embryo. The amniotic sac will fill with amniotic fluid in which your baby will rest and grow for your entire pregnancy.
The entire process of conception progresses very quickly, with little awareness on our part. Only 4 weeks after fertilisation and conception, the neural tube – which connects the brain and spinal cord – has already developed and closed. This tube enables the brain to communicate with the rest of the body. This process relies on essential dietary nutrients including folate and choline for healthy growth, without which, neural tube defects may occur.
Just 10 weeks after fertilisation almost all organs are completely formed. It is during these critical 10 weeks that the embryo is most vulnerable to birth defects and miscarriage. This is why many couples choose to keep their pregnancy to themselves until they’re 12 weeks pregnant. The first 12 weeks of pregnancy, or the first trimester, can be a nervous time for many couples, especially if you’ve experienced multiple miscarriages. Ensuring a healthy diet and reducing stress is very important during this critical phase.