The secrets of conception

Fertility advice you can trust

Conception is a remarkably complex process. The male has to produce a sperm and the female has to produce an egg which then have to come together at just the right time and in just the right place. If you want to give yourself the best chance of conceiving, it is essential that you understand how the male and female reproductive systems work, and what happens when.

Did you know that women produce an egg from alternating ovaries each cycle?

The female

Each cycle, the woman produces an egg from one of her two ovaries, which lie on each side of the uterus (womb). The ovaries are glands which store the eggs in small sacs called follicles. Once the egg is released, fine hairs at the end of one of the fallopian tubes pick it up and waft it down the tube.

The egg then travels down the fallopian tube into the uterus. If it has been fertilised, the egg implants itself into the lining of the uterus (the endometrium). During each cycle the endometrium thickens ready to receive a fertilised egg. (If there is no fertilised egg, the endometrium breaks down and is shed from the body at menstruation, when a woman has a period.)

The male

Male semen contains several million sperm, but only one will be needed for conception, and that single sperm cell contains the father’s genetic contribution to the baby. The sperm need to swim through the cervix, into the uterus and along the fallopian tubes. As they travel, chemical changes mature the sperm so that they become capable of fertilising an egg.


When a couple has unprotected sexual intercourse, the man ejaculates his semen into the woman’s vagina near the cervix, the entrance to the woman’s uterus. The cervix is usually blocked by cervical mucus, but this thins around the time of ovulation (when an egg is released from one of the ovaries) to allow sperm to pass through.

The sperm and egg usually meet in the fallopian tube. A single sperm penetrates and fertilises the egg, which then travels into the uterus where it implants into the uterine lining. Once it has implanted, the growing embryo is sustained by hormones, until the developing placenta can take over and nourish the pregnancy. About nine months after conception, the developing baby is ready to be born.


Related Articles