Positive to negative pregnancy test: What it means

Most women taking home pregnancy tests are quite anxious awaiting the results.  Let's face it, there are only two outcomes and you may be stressed about the results either way.  If you have been trying to get pregnant, then you are excited and hopeful to see a positive result.  If you were not planning on making a baby, you may be stressed out that you have done so and is worried about seeing a positive result. 

Either way, pregnancy tests are a little confusing and can definitely be stressful.  Trying to decipher each test according to the manufacturers' instructions can make you feel nervous, but don't despair.  Take a deep breath and understand that the process is going to be stressful and once you accept that fact, you can move forward.  

Depending upon where you are in your menstrual cycle, you may get different results.  I know, trust me.  You are riding on an emotional rollercoaster.  One minute you are happy about the results and on top of the world, and then a few days later you take another test and you get a different result and now you are sad and disappointed.  It is possible to get a negative pregnancy test after taking one and getting a positive result.  Relax,  Deep breaths...You will need to practice deep breathing anyway, right?

To understand how it is possible to have a positive pregnancy test one day and then a negative result the next day, we first have to discuss how these types of tests work.  Pregnancy tests give you a positive result based upon the level of a pregnancy hormone, hCG, detected in your urine.  When your egg has been fertilized and implanted into your uterus, you are pregnant. 

A placenta begins to form to connect the newly created baby to the uterine wall through the umbilical cord.  The umbilical cord allows the developing fetus to get nourishment from the mother.  The placenta releases pregnancy hormones and this is what the home pregnancy tests are looking for to determine pregnancy--is there an elevated level of the hCG hormone in the body?  If yes, you will get a positive test result.

If your test is positive one day and then negative the next, you are wondering how can that be?  Does this mean you aren't pregnant?  Maybe, but not necessarily.  These tests are very sensitive in that you have to pay attention and follow the directions to the letter. 

If the instructions say to use the first urine stream of the day, but you take the test later in the day after urinating upon rising, you may get a negative result.  Instructions direct you to use the first morning's urine stream because it will contain the highest level of hCG in it.  If you take the test later, there will be less hCG, which may give you a negative result.

If you see a faint line, it could simply be the result of urine evaporation. This occurs when too much time has passed between taking the test and reading the results. If the instructions say to read the test in three minutes, do not wait 15 minutes because this delay in time may affect the results, and it's possible the faint line is just urine evaporation.

The farther along you are in your pregnancy, the darker the line will be in the test.  A faint line doesn't mean you aren't pregnant.  Wait a few days and re-take the test.  If you are pregnant, your body will have made more of the hCG hormone.  The more of the hCG hormone that is present in your body means that the line will be darker if you are pregnant.

The thing with pregnancy tests is that you keep taking them to reassure yourself that you are actually pregnant.  If it has taken you a long time to conceive, you are already incredibly anxious about the results.  You want to be 100% positive before you start relaying the news to anyone.  This is one of the reasons that most home pregnancy test kits come with multiple tests.  You want to be super doubly certain, so you repeat the test multiple times over the course of a few days or weeks. 

Is it possible to have a positive test and then a week later you repeat the test and it is negative? Sadly, yes.  This can occur.  If you have been taking fertility drugs to improve your chances at becoming pregnant, your body already has a higher level of the hCG hormone due to taking these types of drugs.  The fertility drugs can give you a false positive.  

If you are undergoing in vitro fertilization treatments or (IVF), you may get a negative result after a positive.  In IVF, the egg is removed from the woman and the man's sperm is used to fertilize the egg in the lab.  The egg is then implanted back inside the woman.  She is technically pregnant at that time, so there could very well be a positive pregnancy test.  However, even though the egg has been fertilized, it is possible the pregnancy spontaneously aborts and is miscarried.  This is a reason why a week after the positive test there is a negative result after repeating it..

Although most tests claim to be 99% accurate, the accuracy is based on a lot of factors.  Did you use the correct amount of urine? Did you wait the appropriate amount of time before reading the results? How close to your expected menstual cycle are you?  The closer you are to your cycle, the more accurate your test will be.  A faint line may still indicate that you are pregnant.

Because these pregnancy tests have varying degress of sensitivity, you can get different results by using test kits from different manufacturers.  For best results, stay with the same brand when comparing results.  If one kit can detect pregnancy five days earlier than another brand, you could see different results -  one positive and one negative.  It doesn't mean you aren't pregnant. It just means that one test is more sensitive to detecting the hCG hormone than the other one.

Why would your test be negative after a positive test and you have not been bleeding?  It could very well be that the negative result is false.  Did you use the first urine of the day or did you wait until later in the day?  The hCG hormone is strongest after building up overnight, so that may be why you have a negative result a week after the positive.

The fact that you are not bleeding is important.  This is a factor that points towards pregnancy.  If you are certain you followed the directions accurately, schedule an appointment with your doctor.  Your doctor will perform a blood test which will be able to confirm your pregnancy results.

Home pregnancy tests have tremendous advantages.  You can take the test in the privacy of your own home, and you do not have to get in your car and go to the doctor.  You may take the test as many times as you would like to confirm the results. Tests can indicate pregnancy five to six days prior to when you are expecting your next period. 

There are some drawbacks and limitations as well to home pregnancy tests.  You can get incorrect results if you do not follow the manufacturers' instructions precisely.  Even if you have followed the directions exactly, the test itself may have malfunctioned through no fault of your own, and gives you the wrong result.  The test is more accurate the longer that you are pregnant.  If you have sex during ovulation, and take a pregnancy test the following day, you will most likely get a negative result.  It is possible that you are actually pregnant, but it is really to soon to be reflected in the home test.  You need to wait until you have missed your period or are just one or two days from the start of your next cycle and take the test again.

If you have been trying to conceive, odds are that you have already had a prenatal visit with your health care practitioner, and you already know what vitamins you should be taking.  Check with the office to schedule your first appointment because they may not wish to see you until you have missed two periods or you are eight weeks pregnant. 

If this is an unplanned pregnancy, make an appointment with your doctor who will confirm your pregnancy with a blood test.  Your health care provider will advise you on prenatal vitamins, diet and whether medications you are currently taking should be discontinued.

Pregnancy is an exciting time for you and your partner.  Try not to get stressed about everything and enjoy the journey.

References:

https://en.wikipedia.org/wiki/Placenta#/
https://en.wikipedia.org/wiki/Human_fertilization
http://www.firstresponse.com/en/articles-listings/how-pregnancy-tests-work
https://www.compoundchem.com/2018/11/09/pregnancy-tests/
https://www.healthline.com/health/pregnancy/evaporation-line-pregnancy-test
https://www.fertilitytips.com/positive-pregnancy-test-results-vs-test-evaporation-lines/