The menstrual cycle is a series of changes your body goes through in preparation for the possibility of pregnancy. It is governed by a complicated process, involving many different chemicals called hormones produced by the ovaries and the brain.
What is normal?
The menstrual cycle is not the same for every woman and may vary for the same woman. The first day of your cycle (Day 1) is the first day of your period, while the last day is the day before your next period.
Although 28 days is the average cycle length, it is normal to have a cycle that is shorter or longer. A teen’s cycle may be long (up to 45 days), growing shorter over the years.
Most women’s cycles are regular between the ages of 25 and 35 and generally last 21 to 35 days. Cycles tend to be shortest and most regular by age 40 to 42. This is followed by 8 to 10 years of longer, less predictable cycles until menopause (when a woman’s periods stop).
Your menstrual cycle might be regular, i.e. about the same length or somewhat irregular, while your menstrual period might be light or heavy, painful or pain-free, long or short, and still be considered normal.
Within a broad range, “normal” is what is normal for you. Bear in mind that the use of hormonal birth control, such as pills, implants or injectables may alter your menstrual cycle.
Menstrual cycle phases, assuming the average 28 day cycle for purposes of this discussion:
Menstrual phase (Day 1-5)
Why do you get a period?
About once a month, the uterus (womb) is prepared to receive a fertilised egg to start a pregnancy. When there is no fertilised egg, the uterus sheds its lining (Day 1).
• You see this as the monthly menstrual bleeding;
• This will occur every 28 days and in most women lasts for two to seven days;
• You may experience cramping in your pelvis, legs, and back, which can range from mild to severe. These are caused by the contraction of the uterine and abdominal muscles as they expel the menstrual fluid;
Your doctor may recommend medication to ease some of the pain and discomfort.
Follicular phase (Day 1-13)
This phase also begins on the first day of menstruation, but lasts until the 13th day of the cycle.
• The brain releases a hormone (follicle stimulating hormone) which causes several dormant egg cells in your ovaries to grow in sac-like structures called follicles.
• One egg cell becomes dominant and begins to mature, non-dominant follicles shrink and die.
• The dominant follicle secretes a hormone, called estrogen, that thickens the womb’s lining with nutrients and blood vessels in preparation for a fertilised egg.
• Estrogen also causes the appearance of ‘sperm-friendly’ mucus. You may notice this as a thin, slippery discharge.
This phase can be short or long and plays the biggest role in how long your cycle is.
Ovulation (day 14)
On the 14th day the rising estrogen levels cause the brain to release another hormone (luteinising hormone) that causes the follicle to rupture and release the egg cell (ovum), a process called ovulation.
• Usually one ovum is released per cycle.
• Some women have less than a day of red spotting, or lower pelvic pain or discomfort. These symptoms are normal.
•Please note: women with cycles that are shorter or longer than average may ovulate before or after day 14.
The last 4-5 days of the follicular phase, plus ovulation day, are your fertile window when you are most likely to become pregnant if you have intercourse without contraception.
Luteal/ premenstrual phase (day 15-28)
• Straight after ovulation the remains of the dominant follicle produce another hormone (progesterone) that maintains and prepares the uterine lining for potential implantation (attachment) of a fertilised egg.
• The egg cell stays in the fallopian tube (where fertilisation occurs) for only about 24 hours and disintegrates if not fertilised by a sperm cell.
• Some women experience premenstrual symptoms and may feel tense, irritable, emotional, lethargic, depressed or gain water weight and feel bloated, or have tender breasts or acne.
• If fertilisation and implantation do not occur, the remains of the follicle will involute, causing a sharp drop in levels of both progesterone and estrogen, marking the end of the menstrual cycle (Day 28).
Bleeding occurs and your menstrual cycle begins all over again from Day 1.
* Dr Gina Rusike is a general practitioner at Aneni Health Services in Khomasdal and can be reached on 061 212696 or ginarusk@yahoo.com