Can a late period be a sign of cancer? Are late periods really worrying you?

Menstruation normally occurs every 21 to 35 days. After 35 days is a truly late period, and your worry is understandable.

An occasional late period may start between 36 and 40-something days after the start of the last menstrual cycle.

This interval isn’t long enough to be considered a missed menstrual flow, but rather, a late or very delayed period.

A number of reasons can cause your period to be late, and I asked Mary Jane Minkin, MD, clinical professor of obstetrics and gynecology at Yale University School of Medicine, all about the causes.

Just what are the reasons that cause a period to be late?

This assumes that the woman knows she cannot be pregnant.

Dr. Minkin: Anovulation — not having ovulated. Now what can cause that? Perimenopause is certainly one.

As we approach menopause, the poor ovaries just cannot respond to all the FSH (follicle stimulating hormone) and the LH (luteinizing hormone) that the pituitary (gland) sends their way — ultimately, the ovaries will stop producing estrogen, but actually, it is the failure of ovulation that produces the late period.

I thought that you can’t menstruate if you don’t ovulate.

You can get a period from overflow; the lining of the uterus just builds up, and after it reaches a significant accumulation, it just flows out, and it can flow quite heavily.

Thyroid disease is also a common culprit (for late periods). Classically, overactivity (hyperthyroidism) does it; but hypothyroidism can do it, too.

Also, another endocrine disorder, namely elevated prolactin, secreted by the pituitary, can give you late periods.

These women also often have secretion of milk by the breasts.

Prolactin secretion can also be caused by many medications, particularly antipsychotics such as Risperdal.

Also, a medication for nausea like Reglan can elevate prolactin levels.

Of course, depression with stress in and of itself can cause late periods.

Hyper-exercise can screw up periods, even without weight loss.

Eating disorders of course can do it; anorectics seldom get periods. But significant weight gain can do it, too.

Polycystic ovarian syndrome is yet another cause of late periods. Dr. Minkin explains:

This is most often associated with obesity, and most PCOS ladies, because of being heavy, have chronically high estrogen and testosterone levels — so that they never get an LH surge to trigger ovulation, which then makes the progesterone which triggers the period.

Can delayed flow be a sign of serious disease, other than PCOS?

Rarely – they might be just a sign of stress. Something like anorexia is a serious disease, and it does produce amenorrhea, or at least late periods, but as far as something like cancer, no, not very likely.

Cancer of the uterus would more likely present with extra bleeding, not less bleeding.

How often do stress and anxiety cause late periods?

Extremely commonly, and since we really cannot measure stress exactly, stress gets blamed most of the time, when everything else we can measure (like pregnancy, menopause, prolactin, thyroid and PCOS) gets ruled out.

Is there a way a woman can tell if her delayed flow is caused by stress or just a premenopausal body?

The only way would be to measure her FSH level. If it were significantly elevated, you would assume she is in the perimenopausal timeframe.

However, even with a normal FSH, she could be perimenopausal, which we will often diagnose only retrospectively.

If a 40-something woman is experiencing some late periods (beginning on Day 39 or 40, for example, of her cycle), and she’s been suffering an extraordinary amount of stress in the weeks preceding, how likely is stress the cause of lateness, versus being perimenopausal?

Extremely difficult to assess. Perimenopause is often something which takes years, and is very difficult to quantitate.

We do know that the older ovary is less robust, which makes it more vulnerable to stress.

In a nutshell, here is how stress and anxiety trip up the menstrual cycle, causing late periods:

The cerebral cortex of the brain interprets stress in a woman’s life.

This suppresses the cerebral cortex’s efficiency at signaling to the brain’s hypothalamus gland to send instructions to the pituitary gland.

The instructions to the pituitary are supposed to direct it to send a message to the ovaries to ovulate.

This chain reaction gets bungled beginning when the “thinking” part of your brain, the cerebral cortex, feels a lot of stress.

Dr. Minkin is nationally known in the field of gynecology and is often interviewed and quoted in print and broadcast media, including the New York Times, Wall Street Journal and Time Magazine.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  


Top image: Shutterstock/Roman Samborskyi

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