How pregnancy happens

Pregnancy happens when a man’s sperm meets a woman’s egg and fertilizes it. This usually starts during sex, when semen is released into the vagina. Inside that semen are millions of sperm cells, and they begin to swim upward through the cervix into the uterus and then into the fallopian tubes.

Every month, a woman’s body releases an egg from the ovary, this is called ovulation. The egg then travels through the fallopian tube. If sperm are already there, or arrive soon after, one of them may meet the egg. When a sperm successfully joins with the egg, fertilization happens.

After fertilization, the combined cell (now a fertilized egg) begins to divide and grow as it moves toward the uterus. Once it reaches the uterus, it attaches itself to the lining of the womb. This process is called implantation, and it’s what officially starts a pregnancy.

It’s important to know that pregnancy doesn’t happen every time someone has sex, but it can happen if sperm enters the vagina, especially around the time of ovulation. That’s why protection and understanding your body are important if you’re trying to avoid pregnancy.