Can a negative pregnancy test turn positive overnight?

In this article, we will try to answer the question ‘Can negative pregnancy test turn positive overnight?’ The article also tries to give a piece of wholesome information about different aspects of a pregnancy test. The guide explains what is a pregnancy test, how it works. We will also explain, what are evaporation lines, how to differentiate between an evaporation line and a positive pregnancy line, how to avoid evaporation lines and the reason for a false positive and false negative test. 

Can a negative pregnancy test turn positive overnight? 

Yes, it can. If your negative pregnancy test turned positive overnight, do not worry. It certainly does not mean that you are pregnant. 

Every pregnancy test has a time window in which it gives an accurate result. This time frame can be seen in the instruction pamphlet that comes in with the test. If you let the test settle for too long, say overnight, the urine might evaporate from the pad. This evaporation of urine can lead to negative pregnancy test turn positive overnight. 

Notwithstanding, the false-positive pregnancy, for this situation, is because of something many refer to as an evaporation line. Evaporation lines are not characteristic of a genuine positive outcome. 

Evaporation lines happen when the pee that was on the test region begins to dry. The chemical structure of the pee sample changes because of evaporation. Subsequently, the test may begin to show a positive line. After the distributed time has passed, you should dispose of the pregnancy test to evade confusion.

What is a pregnancy test? 

All things considered, in basic terms, a pregnancy test lets you know whether you are pregnant or not. In any case, the inquiry is how? At-home pregnancy test, check for the accessibility of the hormone- human chorionic gonadotropin. This hormone is delivered in people when the fertilized egg joins to the uterine wall and structures the placenta. A blood test can identify the HGC around 11 days after the origination, while a pee test takes 12-14 days after the origination. 

It is seen that the HGC levels increment at regular intervals until 8-11 weeks of pregnancy, and lessening steadily after the conveyance of the newborn child.

How does a pregnancy test work? 

Pregnancy starts when a fertilized egg inserts in the coating of the uterus. The body at that point begins to deliver a hormone called human chorionic gonadotropin (hCG). 

The body’s hCG levels quickly increment during the principal trimester, by and large multiplying each 48–72 hours. Toward the finish of the principal trimester, hCG levels fall. 

Home pregnancy tests work by distinguishing hCG levels during the primary trimester of pregnancy. Tests that can recognize more modest convergences of hCG in the pee are bound to show positive outcomes prior.

The compounds in home pregnancy tests connect with hCG, and a positive outcome will regularly resemble a line, a spot, or an or more sign. Most tests likewise have lines that show that the tests are working. 

Just pee that contains an adequate degree of hCG can make the test’s color stain such that shows a positive outcome.

Types of home pregnancy tests 

There are three types of home pregnancy tests. 

  • Mid-stream tests
  • Dip tests,
  • Dropper tests.

Here is a detailed explanation of the three types of pregnancy tests

  • Mid-stream tests: These are held in the stream of urine for a few seconds and then set aside for a few minutes to wait for the results.
  • Dip tests: Pee in a cup, then dip the test (usually in the form of a strip) into the cup.
  • Dropper tests: With these types of tests, urine is dropped inside the testing well using a dropper that has collected fresh urine from a cup.

For these tests, the main advance is perusing the directions first. Various tests contain various directions, and once in a while, a solitary box of tests contains various sorts, where the guidelines are marginally unique for each test. Make certain to peruse the directions altogether

Evaporation lines vs positive pregnancy line. 

It is important to differentiate between the evaporating line and the positive pregnancy line to avoid the confusion caused. A false alarm for a pregnancy can be the scariest thing possible. A moment ago, you were not pregnant and y=now you are suddenly pregnant. Therefore, it is important to know what an evaporating line looked like in contrast to a positive pregnancy line. 

Evaporation lines are common on pregnancy tests, but they don’t appear every time. It depends on the chemical makeup of each woman’s urine.

An imprint on a pregnancy test might be of an evaporating line if: 

  • Over 10 minutes have passed since stepping through the examination. 
  • The imprint is weak and dry, and it looks like a water spot. 
  • The imprint has no noticeable color in it.

A line on a pregnancy test may show a positive outcome if: 

  • There is obvious color in the line, regardless of whether the shading is weak. 
  • The line shows up inside the period determined on the guidelines, which is generally 3–5 minutes. 
  • A woman has taken an early-result test in any event 11 days after ovulation. 
  • A woman has stepped through a standard exam in any event 14 days after ovulation
  • A woman has missed her period.

How to avoid evaporation lines? 

Evaporation lines are probably going to show up if a woman has not adhered to the directions on the test’s bundling. In order to dodge the confusion, it is important that you follow certain ways to avoid the evaporation line. 

To forestall evaporation lines: 

  • Try peeing in a cup prior to stepping through the examination, at that point dipping the test in the pee for the span indicated on the container. This method forestalls an excess of pee from sprinkling onto the test. 
  • Try not to utilize a pregnancy test that is past its termination date. 
  • Try not to store pregnancy tests in exceptionally hot or cold areas. 
  • Check the outcomes inside 10 minutes of stepping through the exam. Evaporation lines and false positives can show up over the long run.

Reasons for a false positive pregnancy test

A few reasons a lady may have a false positive include: 

  • Permitting a test to sit for a really long time. This can cause a vanishing line that may resemble a weak positive. 
  • Utilizing a lapsed test. This can make a positive line show up regardless of whether the test isn’t positive. 
  • Having a substance pregnancy. At the point when this occurs, the lady is pregnant, yet has an early premature delivery. 
  • Ongoing unsuccessful labor. HCG levels require a long time to drop following a premature delivery. A lady who has as of late had a premature delivery may in any case test positive on a pregnancy test. 
  • Taking certain fruitfulness drugs. Richness prescriptions that raise HCG or that are artificially like HCG can cause a bogus positive. Converse with a specialist on the off chance that you take richness meds, since a home pregnancy test may be less exact.

Reasons for a false negative pregnancy 

The most well-known explanations behind false negative pregnancy tests include: 

  • Not getting enough pee on the test. 
  • Not utilizing pee that is adequately concentrated. Particularly in the soonest days, it’s ideal to utilize the primary morning’s pee. This pee will in general be more focused, and thusly has all the more handily distinguished HCG levels. 
  • Testing too soon. 
  • HCG levels are not rising quickly enough. Some of the time a lady is pregnant, yet her body doesn’t have adequately high HCG levels to continue the pregnancy. 
  • A test that is terminated or in any case damaged. 
  • Not adhering to the test directions, for example, by checking the test too soon or late. 
  • Getting an excess of pee on the test stick, since this may influence the outcomes and weaken a positive. 
  • Not accurately perusing the test outcome. Indeed, even the faintest positive is as yet sure. In the event that there is any line noticeable whatsoever, read the test as certain. 
  • Testing at some unacceptable time. A few ladies outline their period simply by tallying days on a schedule. In the event that your periods are sporadic, you may have the dates wrong. All things considered, it’s smarter to screen your cycles, measure the day you probably ovulated on, and afterward test in any event 10 days after this date. 
  • Utilizing a pregnancy test that isn’t adequately touchy. Some pregnancy tests can just recognize HCG at elevated levels – levels that just happen a few days into the pregnancy. Peruse the test addition to decide how touchy the test is. For the soonest conceivable positive outcome, pick the most touchy test. This implies choosing the test with the capacity to distinguish low degrees of HCG.

The best thing one can do to avoid any sort of confusion is to follow the instructions rightly. This will help in increasing the accuracy of your test. 


In this article, we will try to answer the question ‘Can negative pregnancy test turn positive overnight?’ The article also tries to give a piece of wholesome information about different aspects of a pregnancy test. The guide explains what is a pregnancy test, how it works. We will also explain, what are evaporation lines, how to differentiate between an evaporation line and a positive pregnancy line, how to avoid evaporation lines and the reason for a false positive and false negative test. 

FAQs: Negative pregnancy test turned positive overnight 

What is a chemical pregnancy? 

A chemical pregnancy occurs if a fertilized egg, known as the embryo, is unable to implant, or grow, very early on. This can happen for a wide range of reasons. Chemical pregnancies are thought to be very common, but they typically go undetected if a pregnancy test isn’t taken.

What is an ectopic pregnancy? 

Sometimes a fertilized egg implants itself outside of the main cavity of the uterus. This is caused by an ectopic pregnancy to occur. Ectopic pregnancies usually happen if a fertilized egg gets stuck in a fallopian tube during its journey to the uterus. This type of ectopic pregnancy is also known as a tubal pregnancy. Ectopic pregnancies can also occur in the cervix, ovary, or abdominal cavity.

What if the pregnancy test shows negative but still no period?

Well if the pregnancy test shows negative but still no period, do not panic. It does not necessarily mean that you are pregnant. Women miss periods for many reasons apart from pregnancy. For starters, an excess amount of stress can lead to a delay in pregnancy. Use of a contraceptive, medical conditions like thyroid, PCOD, etc can also cause to delay of periods. 

How long does it take for hCG to show up in urine?

Human chorionic gonadotropin is a pregnancy hormone that usually shows up in the urine 10 days after conception.