The menstrual cycle is the hormonal process a woman’s body goes through each month in preparation for the possibility of pregnancy. The menstrual cycle which is normally counted from the first day of period to the day before the next period isn’t the same for every woman. It can say a lot about your health. To better understand if you’re on the normal or irregular cycle, it is important to know when your last period began and how long it lasted. While menstrual cycle irregularities generally aren’t serious, they can signal health concerns occasionally.
Your Menstrual Cycle and the Relevant Hormones
A normal menstrual cycle starts with menstruation period followed by the release of an egg to a woman’s body every month. During menstruation, the lining of the uterus is shed including blood, cells and mucus.
Day 1 of your cycle is the first day of menstruation. Your cycle ends the day before your next period. While a 28–day cycle is seen as the norm, it can vary and some can experience cycles between 20 to 40 days. Cycles longer than 6 weeks are considered unusual.
The length of your cycle can change throughout your life. Irregular periods are common among adolescent women, and in women who are approaching menopause. A variation in your cycle may indicate a hormonal imbalance. Factors such as stress, weight changes, extreme emotions (good or bad), excessive exercise and traveling can also cause irregularities in your menstrual cycle.
The hypothalamus, a brain structure, causes the pituitary gland to release certain chemicals which stimulates the ovaries to produce sex hormones oestrogen and progesterone. oestrogen and progesterone stimulate the uterus and breasts to prepare for possible fertilization. Premenstrual syndrome or PMS are symptoms that you may experience up to 14 days before your period. Mood swings, feeling irritable, upset, emotional, anxious, tiredness, trouble in sleeping, bloating or tummy pain, headaches and changes in appetite are the most common symptoms of PMS. They usually stop as soon as your first day of period starts. You can study and take-home remedies or talk to your doctor about ways to treat your PMS.
The Phases of your Menstrual Cycle
Your menstrual cycle has 4 distinct phases: starting with menstruation, the follicular phase, ovulation and then the luteal phase. In order to fully understand the cycle, I’ll explain each phase below.
Menstruation occurs when your body expels the broken-down lining of the uterus through the vagina. The length of your period can vary from woman to woman, but generally lasts from 3 to 7 days. The length of your period can also differ from one cycle to the next. The flow is also individual to you and may vary from time to time.
II. Follicular Phase
During this phase, the pituitary gland releases follicle-stimulating hormone (FSH) which causes follicles (cells that contain immature eggs known as ova) to begin developing in the ovary. They produce the hormone oestrogen which causes the lining of the uterus (endometrium) to become thick in preparation for the possible embedding of a fertilized egg. Usually only one follicle develops into a mature egg. This follicle moves towards the surface of the ovary, while the others break down and are reabsorbed by the body. The follicular phase begins on the first day of menstruation and ends with ovulation. It can vary considerably in length, depending on the time of ovulation.
Ovulation is the release of a mature egg from the ovary. During this phase, the rise in a woman’s oestrogen levels causes gonadotropin-releasing hormone (GnRH) to be released from her brain. This in turn causes the pituitary gland to produce increased levels of luteinizing hormone (LH). The abrupt rise in LH, known as the LH surge, triggers ovulation. Following ovulation, the egg is swept into the fallopian tube and moved along towards the uterus. If fertilization doesn’t occur, the egg disintegrates within 6-24 hours.
a. Cervical Mucus
Just before ovulation, you should notice your cervical mucus becomes clear and slippery, resembling raw egg white. It is very elastic and can be stretched into a string between 2 fingers. This kind of cervical mucus is known as ‘fertile mucus’ and I have a blog on it which you may want to read here.
b. When Ovulation Occurs
It is often believed that ovulation occurs mid-cycle. It usually occurs 12-16 days before the next period starts. So if you have a 28-day cycle, you may ovulate mid-cycle between day 12 and day 16. But if you have a 36-day cycle, you may ovulate between day 20 and day 24. Your body will give you clear signs that you are ovulating and if you want to find out more read here.
c. Fertile Window
After ovulation, the lifespan of an egg can be up to 24 hours but is usually between 6 and 12 hours. In contrast, sperm generally survive inside the vagina for up to 5 days if optimal fertile cervical mucus is present. Therefore, your fertile window can be from 5 days before ovulation to 24 hours after ovulation.
IV. The Luteal Phase
During this phase, the remnants of the follicle that released the egg (now called the corpus luteum) release large amounts of progesterone as well as some oestrogen. These hormones contribute to the further thickening and maintenance of the uterine lining. If fertilization doesn’t occur, the corpus luteum breaks down and progesterone levels decline, leading to the disintegration of the uterus lining. During the luteal phase, you may experience physical and emotional changes, called premenstrual tension (PMT) or premenstrual syndrome (PMS), including tender or lumpy breasts, fluid retention, bloating, mood swings, tiredness or anxiety.