Both young girls and women may be seriously concerned by the lack of menstruation over a period of time or even just a single period. While a period may be missed at some point in a woman’s life, the absence of menstruation could indicate more serious pathologies that warrants further investigation. The medical term for the long term absence of a period is amenorrhea. However at times, an absent period may be due to an irregular cycle which is known a oligomenorrhea. Other causes may result in a sudden missed period in women who otherwise menstruate regularly.
Process of Menstruation
The process of menstruation is an important stage in the menstrual cycle as it restores the uterus to a non-pregnant state after the expectation of a possible pregnancy following ovulation.
- The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which stimulates the pituitary gland.
- This chemical message prompts the pituitary gland to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
- These two hormones then stimulates the ovaries to produce other hormones like estrogen.
- It also triggers the release of an egg cell (ovum) in a process known as ovulation.
- Estrogen prepares the endometrium (inner lining of the uterus) for a possible pregnancy.
- Ovulation also prompt the corpus luteum, which is located at the site of the ovarian rupture, to begin secreting progesterone.
- Progesterone acts on the endometrium as well, making it secretory, a necessary state for implantation of the fertilized egg.
- If fertilization does not occur, the levels of estrogen and progesterone drop.
- This causes the endometrium to begin sloughing and the process of menstruation begins.
- After menstruation, all the hormones return to a baseline level.
The menstrual cycle is approximately 28 days which can be measured from the start of one period to the start of the next. This may fluctuate among individuals but a menstrual cycle between 22 to 32 days is considered as normal. Approximately 14 days before the start of menstruation, ovulation occurs. Menstruation can last from 3 to 7 days. To estimate your date of ovulation, refer to the ovulation schedule online calculator.
Differentiating between Amenorrhea and a Missed Period
Missing a single period is not considered as amenorrhea. Similarly missing a few periods followed by a period or two is also not amenorrhea but could possibly be an irregular menstrual cycle (oligomenorrhea). Amenorrhea is when there is a total absence of menstruation for 6 months or more in women who were previously menstruating. This is more specifically known a secondary amenorrhea. Primary amenorrhea is when no period ever occurs by the age of 16 years or if there is no period although the signs of puberty are present.
No Menstruation Causes
The most common causes of absent menses, irrespective of the duration, may include the following conditions :
- Pregnancy or breastfeeding.
- Menopause or premature ovarian failure.
- Polycystic ovarian syndrome (PCOS).
- Severe acute infections, including the common cold or influenza (seasonal flu).
- Stress or emotional shock.
- Starvation or extreme calorie reduction due to dieting.
- Drug (narcotic) abuse.
- Certain prescription drugs including oral contraceptives.
- Discontinuing hormone contraceptives – injection, patch or the ‘pill’.
A number of other possible causes of primary and secondary amenorrhea may also have to be taken into consideration. Any sexually active women who misses a period, irrespective of age, use of contraception or lack of typical pregnancy symptoms should conduct a pregnancy test before considering other possible causes.
Article reviewed by Dr. Greg. Last updated on March 3, 2010