Generally, period-like bleeding is a pretty solid indication you aren’t pregnant, but generally is not always. Bleeding during pregnancy can be mistaken for a period while pregnant, and pregnancy bleeding, especially in the first cycle after conception, is more common than you might expect.
Can you be pregnant and still have a period?
While you can have bleeding around when your period is due and still be pregnant, you can’t have a true period while pregnant. If you are pregnant, ovulation won’t occur, and your uterine lining won’t be entirely shed along with an egg, so by definition, the bleeding isn’t a menstrual period.
What might cause bleeding around when your period is due in pregnancy?
Conception that occurs close to menstruation or low progesterone levels may cause what looks like a period.
Conception may not occur until mere days before your period is due if you have a short cycle or don’t ovulate mid-cycle. For example, let’s say you’re regularly maintaining a 26-day menstrual cycle. Chances are you’ll ovulate around cycle day 13. Even if fertilization occurred that day, it would still take six to twelve days for the fertilized egg to reach and implant in your uterine wall.
By this timeline, your body wouldn’t know to continue producing progesterone, the hormone that maintains the lining of the uterus during pregnancy, until somewhere between day 20 to 25 of your cycle. That could leave as little as one day between implantation and projected menstruation.
If those hormone levels are insufficient, such as in a situation of low progesterone from luteal phase defect, or they had already begun to fall, you might have what seems like a lighter than usual period or light spotting. You might even have what seems like an entirely normal period with heavy bleeding. In a situation like this, it’s possible not to have any indication you’re pregnant until you’re already around eight weeks pregnant.
This type of bleeding is often referred to as “breakthrough bleeding.” It’s the most common type of bleeding mistaken for a period while pregnant and is usually seen during the first month of pregnancy, but it may continue in the first trimester if hormone levels stay low. Basal body temping can be a great way to catch breakthrough bleeding, as after a rise in temperature confirms ovulation, prolonged high temps (more than 16 days) can be an early sign of pregnancy, period-like bleeding or not.
It’s important to note that any bleeding following the first bleed would not occur in a timely, predictable manner like a period. Bleeding in pregnancy will be sporadic with a varying flow. Multiple timely bleeds like a period, whether irregular or light for you or not, are very unlikely to be pregnancy bleeding.
As breakthrough bleeding can be indicative of low progesterone, it’s a good idea to let your healthcare provider know about it if you’ve confirmed you’re pregnant. In fact, any bleeding during pregnancy should be evaluated.
Implantation bleeding could be mistaken for a light period while pregnant.
Many women also mistake implantation bleeding for a light period while pregnant. Following the same example above, if you often have a light period, and had spotting on day 23, you might mistake that spotting as your period a day or two early.
The duration and flow of implantation bleeding vary from woman to woman, but it’s more commonly a light bleed, spotting, or pink-to-brown discharge 6 to 12 days after intercourse that lasts a day or less. It’s rarely heavy and typically won’t contain any clots. You can read a full article or try our quiz on telling the difference between implantation and your period here.
Sporadic bleeding during pregnancy is common in the first trimester.
Finally, there are numerous other causes of light bleeding in early pregnancy. Some examples include:
Cervical changes (blood flow to the cervix increases in pregnancy)
In short, vaginal bleeding doesn’t guarantee that you aren’t pregnant, but if you’re having regular, timely period-like bleeding over multiple months, pregnancy is unlikely. If in doubt, though, especially if you’re also experiencing early signs of pregnancy such as nausea, headaches, tender breasts, fatigue, bloating, food cravings/aversions, or mood swings, a home pregnancy test is the next step. Note that it’s best to wait to take a pregnancy test until at least four days after your period was due or 16 to 19 days after intercourse if you have irregular periods.
If you find yourself with a negative pregnancy test but feel pregnant, you’re not alone. The net is riddled with forum posts presenting a range of variations of this situation all wondering if you can have a negative pregnancy test and still be pregnant. The answer is yes, but a word of realistic caution, excluding testing errors, it’s not common. So, how can you be pregnant but have a negative test? If you aren’t pregnant, why might you still feel pregnant?
Negative Pregnancy Test: Still Pregnant
The test was done too early.
Improper testing time is the most common cause of false negative pregnancy tests. With the high-marketing promises of early-result pregnancy tests, many women have been tricked into having unrealistically-high expectations as far as just how soon a pregnancy test is accurate. When you can take a test depends on a number of factors, including your cycle length, average ovulation, and more. As home pregnancy tests rely on hCG levels to detect pregnancy, and hCG rises very rapidly in early pregnancy, testing even a day too soon can lead to a negative result even if you are indeed pregnant.
While still technically an issue with early testing, in cases, hCG may not rise at the standard rate. In those cases, a test taken in accurate range may still come up negative. Unfortunately, there is no way to judge how quickly your hCG will rise in pregnancy, so there is no way to avoid this possible cause of a false negative pregnancy test.
Some pregnancy complications, such as ectopic pregnancy, can also cause a slow rise. This is an excellent example as to why you should see your health care provider if you have a negative pregnancy test but feel pregnant.
Something went wrong in the testing process.
The second most common cause of false negative pregnancy tests is testing error. This can include a range of issues such as:
-The urine used in the test was too diluted.
-There wasn’t enough urine on the test strip.
-There was too much urine on the test strip.
-The test strip was somehow contaminated (perhaps dropped in another liquid).
-The test was expired or defective.
-The result was read too soon or too long after testing.
-The result was misread (early result lines can be very faint).
All the above are why most pregnancy test instruction packets will recommend retesting no sooner than 48 hours later if you have a negative result. This not only greatly reduces the chance of an error as the probability of the same thing going wrong twice is low, but it also helps eliminate the chance that you tested too early.
The Hook Effect:
Finally, the rarest cause of false negative pregnancy tests, the hook effect. Thanks to misinformation in conception circles, many women misunderstand what the hook effect actually is and how it can occur. In cases where hCG is much higher than it should be, the hook effect can cause a false negative result—this much is true.
The point that is often missed is that the hook effect is usually only seen with hCG levels over 500,000 mIU/mL —many sources quote an even higher level of 1,000,000 mIU/mL. To put that in perspective, the highest point in the generally accepted normal range for hCG in a singleton pregnancy occurs 9 to 13 weeks from your last period at 291,000 mIU/mL. In twins, levels show far more variation, but one study did put that rate at about 1.83 times higher than a singleton pregnancy on average. The hook effect is most often seen in molar pregnancies where hCG levels are not normal.
This means that in a healthy singleton pregnancy, the hook effect is very unlikely to result in a false negative test, and in a twin pregnancy the test would need to be taken several months into the pregnancy for that to change.
Higher than normal levels of hCG-βcf, a form of hCG that’s most prevalent between week 7 to 10 (gestational age 5 to 8), can also cause a hook-like effect in some test brands. Once this issue was discovered around 2009, however, many pregnancy test brands began changing their tests to prevent this error, including First Response and Clearblue, two of the most common test types. Below is a sampling of popular brands tested by the Department of Pathology and Immunology of the Washington University School of Medicine. The white bar represents test results with intact hCG, while the black represents intact hCG mixed with hCG-βcf, and the grey bar is hCG-βcf only. All the tests except the two marked “modified” are before changes were made to detect hCG-βcf. The two modified tests are after changes were made.
Though, hCG-βcf can still interfere with the correct estimation of ‘week’ with Clearblue’s Week Estimator tests. This could be one explanation for why those tests sometimes back track (as is a common scare for those suspecting miscarriage). Even before these changes, this, much like the high-concentration hCG hook effect, was not common. One review of 11,760 ER pregnancy tests in 2013, for example, found only 22 incidents of false negatives as a result of high hCG-βcf, being 0.19 percent of cases.
Negative Pregnancy Test, but Feel Pregnant—and Aren’t
Now that we’ve looked at ways you can have a negative pregnancy test but still be pregnant, let’s look at the alternative, how can you have a negative test but feel pregnant even when you aren’t?
You have high progesterone.
Progesterone is the culprit behind many early pregnancy symptoms, though they are often made more severe by the addition of hCG (morning sickness in particular). However, Progesterone is not just present in pregnancy, in fact, it is also the culprit behind PMS symptoms.
Progesterone is secreted by the corpus luteum, a structure formed from the burst follicle after you ovulate. Its purpose is to maintain the uterine lining for a possible pregnancy, and its levels in non-pregnant women are at their highest just before a period. Those levels just increase in pregnancy.
High levels of progesterone can mimic pregnancy symptoms as a result and may cause you to feel pregnant even if you aren’t. While this can be indicative of some form of hormonal imbalance, the occasional high progesterone cycle is normal. Some of those forms of hormonal imbalance, such as PCOS, can also lead to anovulatory cycles which can lead to seemingly missed periods.
You’re suffering from the power of belief.
Finally, while pseudocyesis is more common in dogs and cats as far as full-blown pregnancy symptoms—enlarged uterus and milk production and all—it does also happen in humans where it is more commonly referred to as phantom or false pregnancy. Medically documented cases of this phenomenon are rare, and usually occur in cases of severe mental stress (for instance, the loss of a child), however, lesser cases that wouldn’t warrant an actual diagnosis are more common.
In short, if you believe you’re pregnant with enough conviction, you just might start to feel pregnant. In other cases, women just notice normal symptoms of their menstrual cycle more and mistake them for pregnancy symptoms.
Always follow up a negative pregnancy test.
Whether you feel pregnant or not, it’s always a good idea to follow up a negative pregnancy test in 48+ hours. If your follow up is also negative, and you still feel pregnant, trust your instincts and see a health care provider. Be sure to let them know you have already taken two home urine tests and would like to confirm via blood testing.
Still have questions? Feel free to drop us a comment. We do our best to help.
Even with the rise of affordable, dollar-store pregnancy tests, the popularity of the DIY pregnancy test continues. The bleach pregnancy test, sugar pregnancy test, vinegar pregnancy test, toothpaste pregnancy test—the list goes on. It seems like according to the Internet, you can pee on or in just about anything to find out if you’re pregnant, but is there any science behind any of it? Do DIY pregnancy tests really work?
The first step, I suppose, in exploring whether DIY pregnancy tests work is to determine how to make a DIY pregnancy test in the first place, and then attempt to determine if there is any logically sound or scientifically proven reason said test would actually work.
The most common DIY pregnancy test methods: The bleach pregnancy test, toothpaste pregnancy test, sugar pregnancy test, and vinegar pregnancy test
The bleach pregnancy test:
Method: place bleach in sterile container, add your urine, preferably first thing in the morning. Note that I could not find clear instructions on just how much bleach should be used. Drain-o is also sometimes switched for bleach.
If the bleach bubbles a lot: pregnant If the bleach doesn’t bubble much, if at all: not pregnant
Supposed mechanism of the bleach pregnancy test: hCG reacts with bleach—or drain-o or something?
When ammonia is added to bleach toxic gases called chloramines are produced. While human urine does not directly contain ammonia, it does contain urea which breaks down into ammonia. As this process takes time, immediate fumes are unlikely to cause adverse effects, but it’s not advised to leave the bleach test mixture sitting for any longer than 5 minutes. The bleach pregnancy test should also be performed in a well-ventilated area should you choose to try it.
Method: Place traditional vinegar in a clean container, add early morning urine (are we sensing a theme yet?) The mix should be 50 percent vinegar, 50 percent urine.
If the vinegar changes color at all: pregnant. If the vinegar stays the same color: not pregnant.
Supposed mechanism of the vinegar pregnancy test: The acidity of the vinegar reacts with the proteins within hCG.
Next, since all of these DIY pregnancy test methods involve urine, let’s talk about what’s in urine that could possibly cause these reactions. Jump to accuracy of the vinegar pregnancy test.
What’s in urine?
The composition of urine varies on diet, hydration level, and health. In general, though, urine is 91 to 96 percent water with the remainder being urea, chloride, sodium, potassium, creatinine, and inorganic/organic compounds such as hormones and proteins. The pH of urine also varies by diet ranging from around 5.5 to 7 with 6.2 being the average. High protein intake is associated with a lower pH, while a diet rich in vegetables and fruits tends to lead to higher pH.
The second question would be…
Does the composition of urine change in pregnancy, and if so how?
During pregnancy the function of your kidneys is altered. Most notably by an increased filtration rate of up to 50 percent! This can reduce the levels of creatinine, urea, sodium, and uric acid in urine. Levels of protein and glucose are often elevated, as well as estrogen and progesterone. The hormone hCG is also added, of course.
As an increased in blood volume also increases necessary water intake, many pregnant women are also dehydrated to some degree. This can lead to darker urine with a stronger smell. The pH of urine is unchanged in pregnancy, though changes in diet, nutrient intake, and a higher risk of infection can sometimes lead to a higher pH.
These changes vary by the stage of pregnancy you’re in. In very early pregnancy, where most ladies might be considering trying a DIY pregnancy test, hCG content would be the only major change.
Examining each DIY pregnancy test: Plausibility and possible accuracy
The bleach pregnancy test:
Verdict: Myth, doesn’t work.
For this test to work, it would have to be true that hCG reacts to bleach. There doesn’t seem to be any suggestion on why this would be, so first I looked at the composition of hCG.
hCG is a glycoprotein, meaning it consists of a complex sugar chain and amino-acid chains (proteins). While bleach can be used to degrade the proteins of glycoproteins, this wouldn’t create foaming.
Second, the hCG content of urine in early pregnancy is very low, and urine is already upwards of 90 percent water to begin with. Traditional pregnancy tests (of the non-DIY variety) don’t actually measure the level of hCG in your urine partially for this reason. Instead, they contain monoclonal antibodies and an enzyme capable of changing the color of a dye. These monoclonal antibodies are designed in a lab to bind to specific molecules (hCG in this case).
If the hCG isn’t what causes foaming, the next question would be if some other change in urine during pregnancy was capable of causing a reaction.
First, one could suggest the same chemical reaction that creates a risk of chloramine gas production creates the bubbling. Meaning someone with a higher urea content in their urine would be more likely to see foam than someone with a lower content. Urea content is often lower in pregnancy, by the way.
More likely though, you’re looking at a simple result of an acid-base reaction. Bleach has a pH of around 12, being very alkaline. As mentioned the average pH of urine is about 6.2 making it slightly acidic—more so on the low end of the scale at closer to 5.5. When you add an acid to a base the resulting chemical reaction creates gas as a byproduct. This gas results in bubbling and foam. This will happen regardless of ammonia content if your urine pH is low. As low urine pH isn’t unique to pregnancy, this would not accurately detect pregnancy.
In short, there is no scientific reason that the bleach pregnancy test would be accurate. What it will tell you is if your urine pH is low.
The toothpaste pregnancy test:
Verdict: Myth, doesn’t work.
There is no element in the composition of hCG that would react to anything in toothpaste. The reaction seen in the toothpaste test is again, a result of pH, not hCG.
Toothpaste contains calcium carbonate, which has a pH of about 9.91 making it alkaline, just like bleach. Adding acidic urine will then cause the same bubbling reaction seen in the bleach test, just with a slightly-less extreme reaction. This is because the difference between the pH range of urine and the pH of calcium carbon is less than that of urine to bleach.
Worse, many toothpaste brands also contain sodium lauryl sulfate. Sodium lauryl sulfate is actually added to toothpaste to create foaming when water is added and the mix is agitated. By pouring in urine and then mixing it, you are adding a substance that is more than 90 percent water and agitating the mix.
This means the toothpaste pregnancy test won’t just not detect pregnancy, it’s also far more likely to give a false positive than the bleach pregnancy test as it doesn’t necessarily require low urine pH to see a reaction.
The sugar pregnancy test:
Verdict: Myth, doesn’t work.
Sugar will dissolve in urine, because sugar is water soluble. However, if there’s too much sugar for urine to fully break apart and surround sucrose molecules (effectively dissolving the solute (sugar) into the solvent (urine)), clumping is the result. You may have seen proof of this in your pantry if you’ve ever left a bag of white sugar improperly stored. If moisture gets into the bag, large hard clumps will form. As a result, a “positive” sugar pregnancy test is just sugar doing what sugar does when limited moisture is introduced.
Temperature is another factor that could affect the sugar pregnancy test. Fresh urine will temp around the same as your body temperature (98.6 °F or so). Within 4 minutes of collection, fresh urine will temp at 90 °F to 100 °F (32 °C to 38 °C). How quickly that sample cools is going to depend on the collection cup, and the ambient temperature of the room.
The warmer a solvent is when added to a solute, the faster it will dissolve because of the added molecular motion. This means very fresh urine may be warm enough to dissolve the sugar on contact (sink in) rather than clump. Depending on the depth of the sugar, there could even be a sink-hole of sorts with a clump at the bottom.
This would actually make sugar more likely to dissolve in pregnancy urine as increased progesterone raises body temperature, but it’s actually far more likely the clump or dissolve question, in this case, comes down to how much urine, how much sugar, and the shape/size of the container being used. Either way, this wouldn’t accurately detect pregnancy.
The vinegar pregnancy test:
Verdict: Myth, doesn’t work.
Vinegar, the traditional white variety suggested for this test, is colorless. If you add urine, which often ranges in color from pale yellow to amber, it will always change colors. So, at first blush it seems any vinegar pregnancy test is going to come back positive.
However, some tests state that the mix may turn slightly green. Vinegar has a pH of around 2.4, making it very acidic. The element in urine that creates color is called urochrome. Urine also contains trace amounts of urobilinogen, formed from the reduction of bilirubin. When exposed to an acid solution these elements separate in such a way that a blue-to-green hue can appear. Levels of urobilinogen are not affected by pregnancy, though, they are elevated in cases of liver strain or disease. Trace levels are normal.
So, there you have it. None of the popular DIY pregnancy test methods actually work according to science. There are a plethora of other options floating about such as soap, salt, etc. All of these methods can be explained by either pH reactions, sodium lauryl sulfate content, solubility, or well, just plain don’t work at all. You’re far better off spending a few dollars on an actual pregnancy test than playing with urine to try a DIY pregnancy test.
If you just don’t want to use a traditional pregnancy test for some reason though, there is one DIY pregnancy test method that is backed by research—and it is also the earliest known form of pregnancy test.
The seed pregnancy test:
In 1350 BC, the ancient Egyptians would determine if a woman was pregnant by having her urinate on barely and wheat seeds for several days. The seeds would sprout in pregnant urine, but not in non-pregnant urine. This method has been tested in two studies, one in 1934, and another in 1963. It was found accurate roughly 70 percent of the time. Researchers suspect this may be a result of the increased estrogen in urine during pregnancy.
Two variety of seeds were used to determine gender in the Egyptian version of this test, however, studies did not confirm that part. If you wanted to try this DIY pregnancy test, it’s far from fast, but instructions are as follows.
Place barely seeds in a plastic bag with a paper towel. Moisten the bag daily with your urine. If within 3 to 5 days the seeds sprout, the test is considered positive. It should be noted that there were cases in the studies linked that seeds moistened with pregnant urine did not sprout, but there were no cases where non-pregnant urine (or even male urine) caused seed sprouting. This makes sense as estrogen levels vary from woman to woman in pregnancy, but are always higher than those who aren’t pregnant. This also suggests a false negative is possible, and a false positive is unlikely.
