Whether you have been trying for months to conceive or don’t feel ready to have a child yet, if you think you might be pregnant it’s likely to bring out all the emotions. Even waiting one day to find out can seem like an eternity. (And let’s be real, no one wants to wait that long!)

Luckily, your corner drugstore or local grocery should have you covered with pregnancy tests you can take at home ASAP. A quick trip to the bathroom, a few minutes of waiting, and the answer will display before your eyes.

But how trustworthy are those results? (Can a stick really know that much about your body?) And what if you’re bleeding or seem to be on your period, will that ruin the test results?

You can take a pregnancy test while bleeding or seemingly on your period, because any blood that mixes with your urine will not affect the results of the test. (However, keep in mind that typically a period is a reliable sign that you are not pregnant.)

Store-bought pregnancy tests that react to your urine are designed to respond to human chorionic gonadotropin (hCG) levels in your urine. The placenta produces hCG, and during the first 8 to 10 weeks of pregnancy, hCG levels rise rapidly. (The hormone levels off around the 10th week and then slowly declines throughout the rest of the pregnancy.)

By the 10th day from ovulation — usually the first day of your missed period — there is enough hCG in your urine for the store-bought pregnancy tests to detect it. Blood from your period will not impact whether or not there is hCG in your urine, so it won’t impact your test results.

However, if your test does come back as positive you may want to do some research into why you’re bleeding.

It’s not possible to have a true period if you are pregnant, because a period involves an unfertilized egg exiting the body. However, there are other reasons why you may find yourself bleeding. Up to 25 percent of women may experience bleeding in the first trimester.

Common causes of bleeding early in pregnancy include:

Implantation bleeding

You may not be far enough along in your pregnancy to get a positive result back on a home pregnancy test if you’re experiencing implantation bleeding, since it occurs when the fertilized egg attaches to the uterine lining.

Because the timing of this frequently corresponds with when your period would be expected, implantation bleeding is often described as a light period or spotting.

When trying to distinguish between implantation bleeding and a period, there are a few hints, as implantation bleeding tends to be lighter in color, last a shorter length of time, and not include heavy bleeding or blood clots.

Changes to the cervix

The cervix may bleed a small amount when irritated from vaginal exams or even sex. It may also bleed due to polyps that can develop in the area, which can also become inflamed or irritated. Bleeding due to these types of cervical irritations tends to be bright red and of a limited amount.

Infection

It’s possible that your bleeding has nothing to do with pregnancy at all! It could be the result of an infection in the pelvic area, bladder, or urinary tract. A serious yeast infection can also cause bleeding. Bleeding due to infections is typically pink to light red in color and spotty/very light.

Molar pregnancy

A molar pregnancy occurs when there is an imbalance in genetic materials. (This can be due to an egg without genetic information being fertilized or multiple sperm fertilizing the same egg.) A molar pregnancy results in mass of abnormal cells in the uterus.

There are both complete and incomplete molar pregnancies, but sadly neither will result in a viable pregnancy. You may experience bright red or dark brown bleeding with a molar pregnancy. Nausea, vomiting, and lower back pains are also common symptoms of a molar pregnancy.

A molar pregnancy has the potential to become cancerous or lead to life-threatening bleeding, so it’s essential to see your doctor and receive treatment (including follow-ups) to ensure good health.

Subchorionic hemorrhage

This is when the placenta slightly detaches from the wall of the uterus. Because the size of hemorrhages can vary greatly, it’s possible for a subchorionic hemorrhage to result in heavy or light bleeding. The color of the bleeding can vary from pink to red to brown depending on the severity of the detachment.

It is also common to feel lower stomach pains and cramping when experiencing a subchorionic hemorrhage. Many women go on to have healthy pregnancies following this, but it can increase the risk of miscarriage in the first 20 weeks of pregnancy.

Ectopic pregnancy

An ectopic pregnancy occurs when a fertilized egg does not attach to the uterus, but instead attaches to the fallopian tube, abdominal cavity, cervix, or pretty much anywhere outside of the uterus.

Besides light to heavy vaginal bleeding, you may also experience sharp waves of pain in the abdomen, shoulder, neck, or pelvis. You may also feel rectal pressure and experience dizziness or fainting.

An ectopic pregnancy left untreated can result in a medical emergency and future fertility issues, so it’s essential to speak with your doctor right away if you show signs of an ectopic pregnancy.

Early miscarriage

Abdominal cramping and back pain along with heavy bleeding may be a sign of a period or a miscarriage. It is possible to mistake a miscarriage that occurs very early in the pregnancy as a period, since many of the symptoms are the same.

A miscarriage may contain more clot-like substances in your vaginal discharge or occur on a day other than when your period cycle would indicate it should.

If you are experiencing heavy blood flow like a period and have tested positive on a pregnancy test, you should seek medical care right away.

Unless you had a positive pregnancy test prior to the start of what appears to be your period, having a period is usually a sign that you are not pregnant.

If you’ve tested positive prior to seeing bleeding, the blood you’re seeing could be spotting related to another cause or a warning signal that something is wrong.

Studies have shown that spotting or light bleeding in early pregnancy is usually not cause for concern, while heavier bleeding episodes — especially when accompanied by pain — are related to a higher miscarriage risk.

It’s important to contact your doctor about further testing, including blood tests or an ultrasound, to determine your pregnancy status if you’re bleeding or start bleeding following a positive pregnancy test.

It can be an extremely emotional time thinking you may be pregnant.

If you want to take an at home pregnancy test to find out, but are worried that blood coming from your vaginal area will impact the results, rest assured you can still safely go ahead. Any blood present with your urine will not impact the results.

It’s highly unlikely that you’re pregnant if you’re experiencing more than just spotting. However, if you have a positive test and you’re experiencing heavy bleeding or bleeding that resembles a period, it’s essential that you seek medical care.

Always remember that no matter the results of a pregnancy test, if you need to talk to a medical professional about your feelings, there are support groups and therapists available to help you.