When pregnancy happens through sex, the following steps must happen:
- An egg is released from the ovary. This is called "ovulation."
- The partner's sperm swim up the vagina, into the uterus, and up the fallopian tubes. (These are the tubes that connect the ovaries to the uterus.)
- When the sperm reach the egg, at least one sperm must get through the outer casing of the egg and make it inside. This is called "fertilization."
- The newly fertilized egg travels down to the uterus.
- The egg secures itself to the wall of the uterus. This is called "implantation."
