You know how it’s supposed to go: A normal menstrual cycle is around 28 days, give or take seven days, and usually the bleeding lasts for up to seven.
This system works most of the time, for most of us. But there can be glitches, whether it’s a missed period, a shorter than usual cycle, or an oddly heavy flow.
Usually, those hiccups are no big deal. “I tell women that one to two abnormal cycles or missed cycles a year is probably okay,” says Mary L. Rosser, MD, PhD, director of obstetrics and gynecology at Montefiore Health System in New York City. “If it’s persistent or consistent, meaning three months or more, then you do need to seek a visit with a healthcare provider.”
In many cases, simple lifestyle tweaks can help. Being underweight, overweight, or exercising really rigorously can all mess with your period. But in other instances, there may be an underlying medical condition affecting your cycle. Periods that come less than every 21 days, more than every 40, or last more than eight can signal trouble. If you’re sure you’re not pregnant (the most common reason for missed periods), one of these conditions may be to blame.
As many as 10% of women of reproductive age have PCOS, a complicated disorder that affects hormones and metabolism. Hallmark symptoms include irregular periods (cycles of at least 35 days for adults and 45 days for adolescents), no periods at all, or lighter or heavier periods.
PCOS is not only a leading cause of infertility; it can also mean other problems down the line. “There’s a real red flag raised when we see someone with PCOS, as it may lead to diabetes and heart disease,” says Dr. Rosser, who is also assistant professor of obstetrics and gynecology and women’s health at Albert Einstein College of Medicine.
Fortunately, there are medications to treat PCOS, and many women respond to lifestyle changes too. “In younger women we say this is an opportunity to maintain a healthy weight and stay active,” Dr. Rosser says.
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The thyroid gland in your neck is responsible for regulating metabolism and can affect your period as well. An overactive or underactive thyroid gland can make it either less frequent or more frequent, absent entirely, or heavier.
When you’re looking for reasons for menstrual irregularities, “screening for thyroid issues is pretty high on the list,” says Karen Carlson, MD, assistant professor of obstetrics and gynecology at the University of Nebraska Medical Center.
Hypothyroidism can be treated with synthetic thyroid hormone. Hyperthyroidism can be managed with one of several different medications. Getting control of an underactive thyroid is especially important if you want to get pregnant.
Uterine fibroids are an overgrowth of muscle cells in the uterus. They’re not cancer, and they’re not life-threatening. But they can cause all manner of uncomfortable symptoms, including heavy menstrual bleeding, especially in women in their 30s and 40s, says Dr. Rosser.
Fibroids that don’t cause symptoms can be carefully watched and not treated, at least not right away. If they are causing symptoms, you can choose from a variety of treatments, most of which preserve fertility. This includes simple diet and exercise changes, oral contraceptives and other hormonal medications, and procedures like freezing the fibroids or cutting off their blood supply. A hysterectomy–surgery to completely remove the uterus–is used less and less to handle fibroids.
Uterine polyps–which grow from tissue in the lining of the uterus–can also affect your period.
Both type 1 and type 2 diabetes have been linked with menstrual issues.
One study found that women with type 1 diabetes, an autoimmune disorder that attacks the insulin-producing cells in the pancreas, may have , longer periods, and heavier bleeding than women without the disease. Birth control pills helped stabilize their cycles, the study reported.
Similarly, women with type 2 diabetes have also been found to have , especially if they are obese, likely due to hormonal imbalances, says Dr. Rosser. When periods are irregular, she says, “it’s good to check for diabetes.”
Endometriosis occurs when the tissue that lines the inside of your uterus–called the endometrium–starts growing outside the uterus. Growths in the ovaries, fallopian tubes, or pelvic tissue can result not only in heavier-than-usual periods (sometimes with clotting) but usually in a significant amount of pain as well.
Your doctor may suggest over-the-counter meds for the pain. Other treatments include hormonal medications (including birth control) and, if those don’t work, surgery to remove the growths. If the endometriosis is especially severe, some women opt for a hysterectomy to remove the uterus.
Being underweight ups your risk of not having periods at all. This can happen to women who exercise intensely, but it also occurs in women with eating disorders like anorexia and bulimia.
Once you get to a certain, very-low weight, hormones are disrupted and you won’t menstruate anymore, Dr. Carlson explains. One study also found that women who may not have periods or may have fewer periods.
These are small tumors that appear on the pituitary gland at the base of your brain. Some of these tumors secrete prolactin, a hormone responsible for prompting your breasts to produce milk. High levels in menstruating women can cause abnormal periods, in a similar manner as thyroid issues, Dr. Carlson says.
Pituitary adenomas are not that common, accounting for less than 1% of women who go to a doctor complaining of abnormal bleeding, she estimates.
Still, it’s important to screen for tumors. “If the tumor is big enough, a woman would need surgery,” she says. Smaller pituitary adenomas may be treatable with medication.
Any other condition that damages the pituitary gland–which also produces the menstruation-regulating hormones luteinizing hormone and follicle-stimulating hormone–can also interfere with your period. The same goes for conditions that affect the hypothalamus, the part of the brain that governs the pituitary gland–even if it’s just stress.
Any kind of blood disorder that causes difficulty with clotting can also result in period problems, says Dr. Carlson. One example is , an inherited bleeding disorder that can cause menstrual abnormalities like very heavy bleeding (think: having to change a tampon or pad every hour or more), bleeding for more than seven days, and clots that are bigger than a quarter.
As many as 24% of women with chronic heavy periods are estimated to have von Willebrand disease, according to the American College of Obstetricians and Gynecologists.
Hormonal meds can often reduce heavy periods but may not always work for women with von Willebrand disease. A nasal spray given during the first few days of a woman’s cycle may help.
PID occurs when the ovaries, fallopian tubes, or other reproductive organs become infected, usually by a sexually transmitted disease like gonorrhea or chlamydia that has traveled up from the vagina.
PID can cause irregular bleeding and spotting, as well as extra-painful menstrual cramps, fever, chills, and discharge from the vagina or urethra.
Antibiotics can zap bacterial infections. Left untreated, PID can lead to scarring and infertility, so if you have these symptoms–especially if pain and fever come on fast–get checked.
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Uterine or endometrial cancer usually strikes after menopause, but because one of the symptoms is abnormal bleeding, it can be confused with symptoms of perimenopause. “We have to be cognizant about irregular bleeding and not blow it off as being perimenopausal,” Dr. Rosser cautions.
Being overweight ups your risk of this type of cancer, and other symptoms include thin vaginal discharge, painful urination, and pain during sex. Cervical and vaginal cancers can also cause irregular bleeding.
Chances are, irregular periods are not a sign of cancer, but it’s always best to get checked out sooner rather than later. “Cancer needs to be ruled out,” Dr. Rosser says. “That’s why we don’t want women to brush [irregular periods] under the carpet.”