The length of a normal menstrual cycle is 28 days, plus/minus 7 days. That is, a period may occur 7 days before the expected date of the period or may be normally delayed for 7 days beyond the expected date. But, if the delay is more than 35 (28+7) days, then the cause of the delay needs to be investigated.
Periods can be delayed for a single cycle or it can be delayed in every cycle. If the delay is in only a single cycle, the most likely cause is a temporary cause like stress. If the periods are delayed but regular in every cycle, then the chances are that the woman has a naturally long menstrual cycle and that this delay in her periods is normal for her.
A long cycle may be normal in some women. So, some women may get their periods normally after every 45 days or 60 days. It may even run in the family. As long as the periods are regular (even if they occur after more than 35 days), it is compatible with fertility and good health and is not a cause for infertility.
But if the periods are irregular in duration, then other causes should be suspected. Most irregular periods which are due to temporary causes like stress, settle down and regularize spontaneously in about 3 months.
If the periods are delayed or irregular for more than 3 cycles, then a medical examination and investigation is definitely called for.
Delayed periods usually occur due to lack of ovulation. If ovulation occurs, periods will generally occur. Estrogen and progesterone secreted by the ovaries during the ovarian cycle causes the endometrium or inner uterine lining to develop. If pregnancy does not occur in that month, the endometrium sheds with bleeding and a menstrual period occurs.
The menstrual period occurs within 14 -16 days of ovulation. This is because the life of the ovum is only 14 -16 days. Once the ovum is released at ovulation, it can have only two options. If fertilized, a pregnancy will occur and the fertilized ovum will develop into a new individual. If not fertilized, it will degenerate and die within 14-16 days. So, when the periods are delayed, it is due to delay of ovulation.
A normal luteal phase (or progestogenic phase) is always of the same duration – 14 days. The length of the estrogenic or follicular phase (the time before ovulation) is usually what determines the length of the cycle. In some cases, a low progesterone level can cause a short luteal phase and early periods. But progesterone levels usually do not cause a delayed period.
In some women, periods can occur in the absence of ovulation – these type of periods are called anovulatory periods. There is no luteal phase since there is no ovulation. Periods may be early or late or even regular.
Causes of Delayed Periods
Pregnancy is the first condition to be suspected when a woman complains of delayed periods, especially if the delay is in only one cycle. Even if the delay in the periods is in more than one cycle, pregnancy should still be considered and either confirmed or ruled out, before thinking of other causes.
Ovulation is generally irregular during breastfeeding. And irregular ovulation will lead to irregular and delayed periods.
Constitutional / Normal Delay
Periods may be normally delayed in the extremes of reproductive life, that is, just at the time of puberty and before menopause. This is because ovulation is irregular or delayed at these times of life.A long cycle may be normal in some individuals. So, some women may get their periods normally after every 45 days or 60 days. It may even run in the family. As long as the periods are regular (even if they occur after more than 35 days), it is compatible with fertility and good health and is not a cause for infertility.
Hormones like those secreted by the pituitary gland, the hypothalamus, the thyroid and the adrenal cortex are active partners in the menstruation process.A low thyroid hormone level (hypothyroidism), a high prolactin level (hyperprolactinemia), a high insulin level (hyperinsulinism) and high levels of androgens and cortisones can suppress ovulation and delay periods.
Causes in the Ovary
Conditions like polycystic ovary syndrome (PCOS) can cause anovulation and delay periods. PCOS is also often associated with high insulin levels, as well as a high androgen level.
Severe stress, unhappiness, frustrations and tensions act on the cortex of the brain. They can effectively suppress the secretion of Follicle Stimulating Hormones (FSH) from the pituitary gland in the brain. A low level of FSH fails to stimulate the ovaries to produce follicles and ovulation and the period is either absent or delayed.
Medicines like oral contraceptive pills, antithyroid drugs, anticancer drugs, antidepressants, steroids and antipsychotics can cause anovulation and delayed periods.
Excessive exercise, severe dieting, especially crash dieting, eating disorders like anorexia, bulimia, severe illness, or sickness for an extended period of time can cause anovulation.
Treatment is as per the cause. If the cause is hormonal, medicines to bring the hormone levels to normal is necessary. If conditions like PCOS, or anorexia nervosa is the cause, then appropriate treatment should be started. If tests rule out any underlying abnormalities, and it is diagnosed to be due to stress, exercise, dieting etc. then assurance is all that is necessary.