Let’s take a deeper look to get a better understanding of what exactly occurs in the body during ovulation process. This ovulation graph displays what’s happening in your cycle around ovulation.
The cycle is the time from the first day of your period to the first day of the next period. Most women have a menstrual cycle that lasts between 28 to 32 days on average, but for others it might be as short as 21 and as long as 35 days. Your menstrual cycle tends to be longer in the first few years after menstruation begins and then become shorter and more regular over time.1 Because there are such differences in the length of women’s cycles, it can be difficult to determine your ovulation window. As already mentioned a cycle is considered to have a normal length if it lasts between 21 and 35 days. Having an irregular cycle is very common, in fact more than 70% of women have a fertile window that occurs before day 10 or after day 17 of their menstrual cycle.2 For women with irregular periods, keeping track of their cycle becomes even more difficult. If your period happens very frequently, rarely or the time between your periods start to change there is a risk that you have an irregular period. Other signs of irregular periods are if the period lasts more than 8 days, is late, early or missed.3 Types of irregular periods include:
- Oligomenorrhea (only six to eight period per year)
- Metrorrhagia (frequent periods but occur irregularly)
- Menometrorrhagia (long, heavy and frequent periods that occur irregularly)
- Amenorrhea (no period from 3 months on)4
The entire ovulation process is regulated by hormones. During your cycle your body produces five different hormones. The gonadotrophin-releasing hormone (GnRh), follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone. They are produced in different parts of your body and regulate what happens during your cycle.5 The process is broken down into three main stages, each of which is distinct due to the ways in which hormones are elevated during that phase.
The first phase of a woman’s cycle is the periovulatory, or follicular phase. This stage is started in the brain, when the hypothalamus produced GnRh. This hormone then tells the pituitary gland – which is a tiny organ in the brain – to produce FSH.6 FSH is responsible for the ripening of the eggs in the ovaries and the production of estrogen. Then a mucus forms around the ovum, and the uterus thickens. This step is important in case fertilization should occur.7
Next, the ovulation phase itself, also known as the ovulatory phase, takes place. During this time the luteinizing hormone is produced by the pituitary gland and signals the most mature egg to be released. The ovum and its accompanying cells exit the follicle through a hole created by enzymes. The ovum makes its way to the fallopian tube. When the ovum is in the fallopian tube it can be fertilized by a sperm. This is the time when women are most fertile and the sperm has between 12 to 24 hours to fertilize the egg. This is the timeframe during which women are most fertile, and it typically lasts for a period of 24 to 28 hours. If the egg is not fertilized it will leave the body together with the lining of the uterus, which is when you get your period.
Finally, there is the postovulatory, or luteal phase. This is when LH is secreted. The egg cell stays in the fallopian tubes for maximum 24 hours. If fertilized, an egg will become implanted in the womb. On the other hand, if the egg does not become fertilized, it stops producing hormones and disintegrates. This is also when the uterus lining begins to break down in preparation for menses.8
The menstrual period usually lasts three to five days. The lining of the uterus, which builds up in the periovulatory phase, is needed for pregnancy. If pregnancy does not occur, the body will shed this lining. This is what causes the bleeding during menstruation. If you do get pregnant, the fertilized egg will travel down to the lining of the uterus and therefore no bleeding will occur. While each woman has a unique menstrual cycle and therefore will ovulate at a different time from the next, there are a few ways that you can track your cycle, which we will discuss in the next section. [avafootnote]
- Mayo Clinic. (2013 April 16). “Menstrual cycle: what’s normal, what’s not.” Retrieved November 19, 2015, from http://www.mayoclinic.org/healthy-lifestyle/womens-health/in-depth/menstrual-cycle/art-20047186?pg=1 ↩
- Wilcox, A., Dunson, D. and Baird, D.D. (2001, January 6). The timing of the “fertile window” in the menstrual cycle: day specific estimates from a prospective study. Retrieved November 23, 2015 from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC27529/ ↩
- Sheehan, J. (2010, February 02). “The Facts about Irregular Periods.” Everyday Health. Retrieved November 19, 2015, from http://www.everydayhealth.com/pms/irregular-periods.aspx ↩
- Pagano, T. (2014, November 07). “Treating Irregular Periods”. WebMD. Retrieved November 20, 2015, from http://www.webmd.com/women/guide/treating-irregular-periods?page=3 ↩
- BabyCenter. (2013 April). “How your menstrual cycle works.” Retrieved November 20, 2015, from http://www.babycentre.co.uk/how-your-menstrual-cycle-works ↩
- Klibanski, A. and Tritos, N. ( 2013 May). “Pituitary Disorders.” Hormone Health Network. Retrieved November 20, 2015, from http://www.hormone.org/diseases-and-conditions/pituitary/overview ↩
- BabyCenter, see above. ↩
- Crosta, P. (2015 July 20). “What is Ovulation? What is the Ovulation Calendar?” Medical News Today. Retrieved, November 03, 2015, from http://www.medicalnewstoday.com/articles/150870.php ↩