Menstrual cycle and Pregnancy are two important experiences that ovulation dictates every month.
Each month when an egg is matured at any of the ovaries, it is released at ovulation, entering the closest inlet of the Fallopian tubes to travel down into the uterus. About the same time egg is released, the lining of the uterus begins to thicken and the mucus in the cervix becomes thinner to allow for easy movement on the lining.
As the ripe egg travels down the Fallopian tube, it is within the tube that a man’s sperm should be introduced to fertilize the gliding egg, and this is why couples must have sex about this time.
Usually, a woman trying for a baby should begin to have sex about 4 days before she ovulates, through to about 2 days after ovulation. This is a piece of advice, and not a rule. You can have sex once in 48 hours during the fertile days. Everyday sex is safe for would-be-dads who have normal sperm count.
About the same time of ovulation, the lining of the uterus begins to thicken and becomes thick enough for the budding egg to stick or implant itself to it, if already fertilized before getting into the womb (uterus).
But, if the ovulated egg were not fertilized by sperm, it would discharge out of the uterus through the vagina. Quite often, most women don’t notice it when the unfertilized egg passes out.
Then, the lining of the womb that became thick to allow fertilized egg implant itself to it, begins to shed; leading partly to the monthly period of bleeding.
And the cycle continues with your pituitary gland releasing the hormone that causes ovaries to produce new egg follicles for ovulation to take place again.
Could you figure out anything in the explanation of Menstrual cycle and Pregnancy above? Egg was present and perhaps sperm but zero fertilization. There was a missing in action "Goaless ovulation"!
According to the American Society for Reproductive Medicine, an average Menstrual cycle ranges between 21 and 35 days.
Most women have about 28 days menstrual cycle and for some, the cycle may be shorter or longer and still be considered normal. In which case, ovulation may occur much earlier or later than the estimated usual 28 days interval.
The varied menstrual cycle accounts for the difference in the date of ovulation from woman to woman. See the explanatory pregnancy infographic about menstrual cycle and ovulation as below.