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You’re out running errands on a normal afternoon, then you stop to take a bathroom break and notice there’s… uhh… blood spots on your underwear. But your period isn’t supposed to arrive for another week.

Not only is this a nuisance, but it can also be a bit unsettling. Your mind might start wandering to all kinds of extreme scenarios — is it some form of infection? Hormonal imbalance? Pregnancy? Why am I spotting before my period?

There’s good news and bad news here. On the one hand, you don’t need to freak out immediately. Spotting can happen for all kinds of reasons, and most of them aren’t anything major to worry about.

The unfortunate news is that it can be challenging to decipher what exactly is going on in your body. You’ll have to look at various factors (like cramping, recent sexual activity, and any other physical symptoms) and potentially talk to a doctor to learn more about your specific situation.

Here’s a list of everything that spotting before your period could indicate.

If you experience spotting every month in the weeks before your period, it could be connected to ovulation.

Around 3 percent of women experience bleeding during ovulation, those few days mid-cycle when the egg is being released from the ovary and into the fallopian tubes. You may also experience some mild cramping and discomfort.

When a fertilized egg attaches to the interior lining of the uterus, 6 to 12 days after conception, implantation bleeding can occur.

One-third of pregnant women experience spotting with implantation. It’s usually accompanied by breast tenderness, mood swings, or nausea, and a pregnancy test can detect an early pregnancy within a few weeks.

If you recently started on a new hormonal medication or contraceptive method, you may notice some odd bleeding patterns that don’t track with your usual monthly flow.

Spotting could even start to replace your regular period entirely. This isn’t usually a problem and might be your body’s adaptation to the hormonal changes.

Queue the Lonely Island anthem 🎶“I just had sex, and it felt so good” 🎶

Only, if it didn’t feel good, and if you experienced tearing because of a lack of lubrication and increased friction, you may bleed a little afterward. If post-sex bleeding or discomfort is a regular issue for you, it’s worth seeking out the help of a doctor to figure out the root cause.

Sex should be fun and pleasurable — not painful.

If you’ve had unprotected sex recently (oops), you might want to call your doctor to get tested for STIs. Early symptoms of chlamydia and gonorrhea include bleeding between periods, along with painful urination, odd-smelling discharge, itching, and pain during sex.

Pelvic inflammatory disease (PID — not to be confused with P.O.D.) is what sometimes occurs when you don’t get those early STIs treated right away.

Gonorrhea or chlamydia spreads from your vagina and cervix into your upper genital tract, including the fallopian tubes and uterus. PID may be accompanied by fever or abdominal pain, and it needs to be treated ASAP to avoid ectopic pregnancy or infertility.

In rare cases (1 out of every 50 pregnancies, according to the American Academy of Family Physicians), a fertilized egg may implant itself outside the uterus.

The egg can’t properly grow there, so an ectopic pregnancy needs immediate medical attention to avoid serious bleeding and complications. Other symptoms include sharp waves of abdominal pain and dizziness.

Endometriosis is a complicated pelvic disorder in which the tissue normally present in the uterine lining is found somewhere outside the uterus, such as the ovaries, fallopian tubes, or abdominal area.

It causes pelvic pain, moderate to severe cramping, and heavy or irregular bleeding. While there’s no definitive cure, the symptoms of endometriosis can be treated with medication or surgery.

Polycystic ovarian syndrome is the most common hormonal condition for reproductive-aged women and affects up to 27 percent of women during these years.

It occurs when the body overproduces androgens, which leads to physical symptoms such as irregular and painful periods, spotting, acne, hair growth, and weight gain.

Symptoms of PCOS can often be treated with lifestyle changes or hormonal birth control.

Women in their mid-30s to late 40s who are approaching menopause go through a transition period called perimenopause (literally translated as “around menopause”).

During this time, the estrogen in your body is fluctuating, which can cause changes to your menstrual cycle — it may become longer or shorter, lighter or heavier, and may include spotting.

People in perimenopause are also likely to experience other menopause symptoms like hot flashes, vaginal dryness, and sleep issues.

If you’ve gained or lost an unusual amount of weight recently, this might be messing with your hormones and sending your menstrual cycle out of whack.

Eating disorders and extreme weight loss can cause amenorrhea (the clinical name for loss of a regular period), and this likely needs doctor intervention to get your body back on track.

Viruses like the flu or mono are no fun. They force you to cancel plans, wreak havoc on your energy levels, and yes, they can also affect your menstrual cycle. Thankfully, though, your cycle should regulate itself in a month or so, after you recover.

If you’ve got a lot on your plate lately and notice it’s affecting your eating patterns, sleep, and overall well-being, know that it could also be causing some hormonal changes that might induce mid-cycle spotting.

Try to limit your stressors or work with a mental health professional to get your mind into a healthier and happier state.

Uterine polyps are tissue growths that occur in the inner lining of the uterus. They’re usually benign and are most likely to develop in women between 40 and 50 years of age (though they can also grow in younger people).

Polyps can affect fertility and mess with your regular menstrual cycle, so in some cases, you might choose to have them medically removed. Your doctor may also recommend removal so the polyp doesn’t develop into a cancerous growth.

Fibroids are abnormal growths of tissue and muscle in the uterus. Fibroids can grow in the uterine lining, within the uterine walls, on the surface of the uterus or some combination of those areas.

Both can cause bleeding but are usually noncancerous; however, it’s worth getting them checked out by a doctor, especially if they’re causing irregular periods.

Fibroid symptoms can also be treated with medication or medical procedures — talk with your doctor to learn more.

Cervical, endometrial, and ovarian cancer cases are uncommon, but unfortunately, they are a reality for a number of women each year.

All three of these cancers can cause spotting and light bleeding. For women who’ve already gone through menopause, spotting is a major red flag and should be further examined by a healthcare professional.

Did you accidentally leave a tampon in and forget about it? Or did a condom get stuck in your vaginal area during sex?

If these objects aren’t promptly removed, they can cause a number of problems, including strong-smelling discharge, irregular bleeding, itching, or increased body temperature.

Toxic shock syndrome is also a thing, so you should never leave a tampon in for more than 8 hours.

Light bleeding during the first trimester of pregnancy is considered normal. But if this spotting gets heavier and is accompanied by pain in the pelvic area, it could be a sign of a miscarriage.

The spotting will usually turn into heavy bleeding within a few hours, and then back into irregular spotting for another 1 to 2 weeks.

What you think is menstrual spotting might actually be connected to a urinary tract infection. UTIs cause painful urination and may also cause bleeding from the urinary tract due to inflammation.

Any type of thyroid disease (including hypothyroidism and hyperthyroidism) could affect your menstrual cycle. Thyroid issues can also lead to early menopause. Thyroid hormone can typically be regulated with medication.

An assortment of other health issues can affect your period, including kidney and liver diseases. A doctor can help you figure this out if the cause of your spotting remains unknown.

In general, if your spotting is accompanied by pain of any kind, or it if persists for more than a couple of months, it’s smart to consult a healthcare professional. Your doctor can help you examine everything from your lifestyle to your medical history to understand what might be happening.

If you’ve already gone through menopause, menstrual spotting shouldn’t happen and could be a sign of cancer — so schedule an appointment ASAP. Pregnant women should also monitor spotting closely and see a doctor if it becomes heavy or painful.

Being aware of your body is key here. It’s not uncommon for your normal cycle to be disrupted because of an illness or lifestyle stressor, but if it doesn’t balance itself back out (or if you’re experiencing discomfort), that’s when it’s time to call in the experts.