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The First Step to Understanding Your Fertility? Knowing Your Menstrual Cycle.

Image of Menstrual Cycle

The first step to understanding your fertility is to understand your monthly cycle. Understanding the phases of your menstrual cycle will help you understand the natural process your body is going through, and when you are most likely to conceive.

The menstrual cycle is a naturally occurring function in women of reproductive age. The average length of the cycle is 28 days and is comprised of four phases: menstruation, the follicular phase, ovulation, and the luteal phase. Each month, this cycle will result in either pregnancy or menstruation.

During the menstrual cycle, your body undergoes many physiological and hormonal changes. The process begins with your brain triggering certain hormones to stimulate egg growth. Once the egg matures it will release from the ovary and travel through the fallopian tube into the uterus. If the egg is not fertilized by sperm, it will disintegrate and be absorbed. When the egg goes unfertilized, hormone levels will drop causing the lining of the uterus to shed and bleed resulting in a discharge through the vagina. Bleeding (also known as your “period”) will last around 5 days.

Days 1-5: Menstruation

During menstruation, your body realizes that the egg from the previous cycle did not fertilize or implant. The estrogen and progesterone hormone levels will begin to drop causing the lining of the uterus, called the endometrium, to shed and bleed through the cervix and vagina. This bleeding lasts an average of five days and consists of blood, mucus, and tissue.

The first day of menstrual flow is considered the first day of the next menstrual cycle. During this menstrual phase, your pituitary gland produces a hormone called FSH (Follicle Stimulating Hormone). This hormone level rises and triggers the next phase in the menstrual cycle where your body begins to prepare for another reproductive cycle.

Days 1-13: The Follicular Phase

At the beginning of your menstrual cycle the pituitary gland (located at the base of your brain) produces increasing amounts of two hormones – FSH (follicle stimulating hormone) and LH (luteinizing hormone). FSH works on your ovaries to stimulate approximately 10 to 20 egg-containing sacs known as follicles.

At around day five, increasing amounts of LH are released to help these follicles mature. As these follicles in the ovaries mature they begin to produce a hormone of their own called estrogen. Estrogen works to stimulate more LH production which continues the maturation process of these follicles.

Around day eight of your cycle, one of these developing follicles will emerge as the dominate one and all the others will begin to shrivel and disintegrate. Around the twelfth day, the increasing level of estrogen is also causing the lining of your uterus to thicken as it prepares for the implantation of a fertilized egg.

Days 10-18: The Ovulatory Phase

The Ovulatory Phase of the menstrual cycle occurs in the middle of your menstrual cycle. An increase in the the luteinizing hormone (LH) level causes the mature follicle to burst and release the egg, usually around day 14. This is what is commonly called ovulation. From the ovary, the egg travels to the fallopian tube where it awaits potential fertilization by a man’s sperm.

The best days for conception generally occur from days 11 to 17 – the days leading up to and immediately following ovulation. If the egg is not fertilized, it will dissipate within 12 to 24 hours.