Conception is the all-encompassing term given to the general act of becoming pregnant. For most soon to be parents, conception refers to the moment that they create the miracle of life.
How does conception happen?
Conception occurs after sex, when the sperm from a man’s ejaculate and the ovum from a woman’s ovary merge together to form a viable zygote, or fertilized egg, which then implants in the uterus as an embryo and grows over 9 months to become a baby. Conception can also be assisted in the processes known as intrauterine insemination (IUI), in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ISI).
What is sperm, and where does it come from?
Sperm, or spermatozoa, is the male gamete, or male reproductive cell that carries the genetic information that will, along with the female gamete, make up the complete set of chromosomes that develops into an embryo. Besides the obvious importance of a sperm cell, they also carry one more huge responsibility in the conception process – whether the sperm possesses the chromosome X or Y determines the gender of the baby.
A man’s body produces billions of billions of sperm cells in his life. The number is astronomical. It takes on average 2-3 months for a sperm cell to mature to the point of being released through ejaculation, along with around 300 million others in each output of such. Sperm cells are the product of the typically male hormone Testosterone. Production of sperm originates in the two glands in the scrotal sac beneath the penis. Sperm thrive in temperatures of 34 degrees Celsius, around four degrees cooler than the average body temperature, which is why they are stored in the testicles which hang outside the body. The sperm, once created, is stored within a 6 metre long, coiled tube until just before ejaculation, where it is scooped up and mixed with semen.
What is an ovum, and where does it come from?
An ovum, or egg, is the female gamete, or female reproductive cell that carries the genetic information that will, along with the male gamete, make up the complete set of chromosomes that develops into an embryo.
The ovum, or egg, is formed inside the ovaries of a woman on a regular cycle, and released regularly in the process known as ovulation. Women are born with the building blocks to all the eggs they will ever produce, these are commonly known as ‘fertility opportunities’, and normally number in enough for on average around 1-2 million. During a woman’s life she will lose around one half to three quarters of these fertility opportunities before she even reaches puberty and starts to menstruate, in a process known at atresia. With each cycle of ovulation a woman uses approximately 1000 fertility opportunities, even though only one mature ovum is produced.
During ovulation, the mature ovum is released from the ovary into the fallopian tube, where it may be fertilized by the sperm and implanted into the womb. If the egg remains unfertilized it will slowly stop producing hormones, which causes the lining of the uterus begins to break down and exit the body in the process of menstruation.
How does the sperm fertilize the ovum?
Before the sperm makes it to the ovum, there has already been a flurry of activity leading to the act of it penetrating the egg. Even though millions upon millions of sperm are released in each ejaculation, only one single sperm cell is required to fertilize each egg.
Once those millions of sperm make it through the cervix, whether aided or hindered by the cervical mucus, they still have a long way to go. The path from cervix to fallopian tubes via way of the uterus is about 18cm, and can be traversed in as little as 45 minutes by a fast swimming cell. The trip can also take significantly longer, up to 12 hours. Once in the fallopian tubes the sperm can survive for up to 7 days waiting to find an egg, hence why you can still fall pregnant even if you don’t have sex at the exact moment of ovulation.