What Happens if a Couple Has Sex Near the Time of Ovulation?
Sperm from the guy's penis enters the vagina when he ejaculates (a little is also released just before!). To help his sperm travel, she secretes a watery mucus. The sperm find their way from the vagina through her cervix and uterus, and eventually travel out to the ends of her Fallopian tubes. There they search for an egg, sometimes waiting more than four days. If they find the egg, the sperm attempt to penetrate it. Fertilization is the successful joining of an egg and sperm, triggering the start of a pregnancy.

As soon as fertilization occurs, the genetic material within the two sex cells (egg and sperm) combines. Shortly thereafter the new embryo-to-be begins dividing: one cell becomes two cells. Two becomes four. Four becomes 16. (You get the point.) After three days, the microscopic cell mass travels down the Fallopian tube and burrows into the thick lining of the uterus. In most cases, approximately eight-and-a-half months later, a baby is born.

What happens when there's no fertilization by sperm? If fertilization doesn't occur within 1 to 2 days after the egg is released, the egg dies. As a result, estrogen and progesterone levels drop. Pregnancy won't happen during that cycle. This withdrawal of hormonal support causes the built-up uterine lining to shed. This is called a period, or menses, or menstrual flow! It usually lasts three to six days. At this point, the stage is now set for the entire cycle to repeat: the brain notices the low estrogen levels and starts to stimulate the ovaries again.

What's important to remember from this is pregnancy can happen at almost any time of the month! Ovulation isn't always predictable and the millions of sperm released are both patient and determined in the quest to find an egg. The only way a sexually active couple can reliably prevent pregnancy is careful, consistent use of a birth control method. Understanding how human fertilization works is a great first step as well. Remember that having a child is obviously a huge responsibility. It's also one of life's greatest experiences, but we all know it's best to wait until both of you are ready!

Be safe out there on the highways of love!