False Positive Pregnancy Test – Get to Know about Home Pregnancy Test Kit Usage

You must have read about the home pregnancy tests which are almost accurate. But many of us may experience the misfortune of a menstrual cycle within some days after getting a BFP (big fat positive) on a pregnancy Kit. It will only lead to sadness and discouragement and you will be wondering whether the test was wrong, and gave you a wrong positive result and just false hopes.

It is also true that some of the reputed brands of home pregnancy tests are nearly 97 to 99% accurate. But that doesn’t mean it will make you feel better and also it is not likely that test was wrong technically in telling a positive result for conception. It implies the test was performed as per the directions indicated.

When to take a pregnancy test?

The best time to take a pregnancy test is at least a week after your missed period.

How does home pregnancy test kit work?

While performing the test one should keep in mind that home pregnancy tests only work by detecting the particular level of hCG (Human Chorionic Gonadotropin) also known as ‘pregnancy hormone’ in the urine. For more information on how to take the test, read: How to use pregnancy kit.

When does the home pregnancy test kit give a positive test result?

1. The placenta will start secreting hCG after embryo implants into the uterine wall.

2.  The hCG amount will increase exponentially in the first pregnancy week itself.

3. While non-pregnant ladies do have a small amount of hCG (5 mlU/ml) circulating in the blood.

4. So, home pregnancy tests are not sensitive enough to detect such low hCG level.

5. Therefore, you will get a positive test result only when it is able to detect enough hCG for indicating pregnancy. It is also true for a blood pregnancy test which is performed in labs.

But the question is why did you receive a positive result and then just after a few days your period starts. What are the possible causes of False Positive Pregnancy Test?

a- Chemical Pregnancy-The reason behind getting a false positive result is you did conceive successfully but have faced a very early miscarriage, which is often termed as Chemical Pregnancy. It is found that about 70% of conception ends up in miscarriage. Without even realizing, many women experience chemical pregnancy as miscarriage occurs immediately after conceiving and the periods start on time. But who is trying to conceive, it is not like any pregnancy type will go unnoticed. You can also use early detection pregnancy tests; it is possible to know the pregnancy just after ovulation. The excitement that is received by confirming the pregnancy with early detection home pregnancy test can be balanced by creating awareness about early miscarriages.

b- hCG trigger shots– For stimulating the ovulation, fertility specialists give shots to hCG. It acts like a luteinizing hormone and helps in rupturing the follicle which carries the egg to push the ovulation. It depends upon the hCG dosage shot given, it can probably take up to two weeks for hCG shot to clear from the body. As a result, getting an hCG shot during the cycle course can potentially produce a false pregnancy test.

Keep in mind the following instructions for ensuring HPT accuracy after hCG trigger shot:

1- Wait for at least 2 weeks or 14 days after 10,000 IU injection

2- 10 days after 5,000 IU injection

3- 7 days after getting 2,500 IU injection

c- Evaporation lines– You will read an instruction stating that read the HPT result of the test within a given time slot which is typically within 5 minutes. This is not letting you to confuse it with the urine evaporation lines appearance with a faintly positive test line. Though it is normal for evaporation lines to appear on test strip once the urine dries. But if you saw the test after the recommended time frame, then there are chances of the false-positive result because of an evaporation line.

d- Ectopic Pregnancy: Sometimes, fertilized egg embeds itself outside the uterus’s main cavity. This results in ectopic pregnancy. These pregnancies usually occur when a fertilized egg stuck in a fallopian tube while moving to the uterus. This can be due to tube’s scar tissue, misshapen, inflammation or have a past uterine infections history. This type of pregnancy is also known as tubal pregnancy.  The embryo is not achievable as there is no place for it to grow or develop outside the uterus. Symptoms of ectopic pregnancies are:

1. Sharp pain in the abdomen, pelvis, shoulder or neck
2. Nausea and sore breasts (Similar symptoms of a normal pregnancy)
3. Pressure on the rectum
4. Severe pain on one side of the abdomen
5. Light to heavy vaginal spotting or bleeding
6. Dizziness or fainting

e- Recent abortion or miscarriage: Even after having miscarriage or abortion you will keep getting a positive result for pregnancy. Once conception is achieved, hCG levels rise continuously as placenta develops, keep doubling every few days and is at peak around 10 weeks.

But once the pregnancy ends, hCG levels start reducing slowly. The hormone can stay in blood and urine for nearly 6 weeks after the pregnancy loss. So, it is possible to get a false-positive test until the hCG hormone returns to pre-pregnancy position.

f- Error on your behalf: It is very important to follow the directions mentioned on the package exactly and then check the expiration date before using. Even after following the instructions, there is always a chance of user error. One common mistake is taking the test very early during the cycles. It can either cause a false-negative or false-positive result. It is advised to take the test when urine is not diluted with water excessively and is concentrated i.e. during the first wake up in the morning.

g- Medications: You must be taking fertility medications if trying to achieve pregnancy under doctor’s guidance. Apart from hCG trigger shots, other medications that can cause a false-positive pregnancy test are:

1. Antianxiety medication such as diazepam (Valium) or alprazolam (Xanax)
2. Antipsychotics like clozapine or chlorpromazine
3. Anticonvulsants like Phenobarbital or other barbiturates
4. Diuretics such as furosemide (Lasix, Diuscreen)
5. Parkinson’s disease medications including bromocriptine (Parlodel)

h- Other medical conditions can also cause a home pregnancy test to give the false-positive result. It includes:

1. A urinary tract infection
2. Ovarian cysts specifically in corpus luteum cysts
3. Serious diseases in ovarian cancer
4. Rare cases of pituitary problems

How to confirm a positive pregnancy test?

1. You must follow up with the doctor’s appointment after getting a positive home pregnancy test result.
2. The doctor will give you a urine or blood test for confirming the result and will observe the hCG levels.
3. You will also have to go through the transvaginal ultrasound for looking the gestational sac to confirm the pregnancy is proceeding ahead.

If you are planning to play a prank on your friend then you must read how to get a fake positive pregnancy test! Also, are you confused with the usage of Nimesulide drug during pregnancy? If yes, then read our article on Nimesulide tablet which talks about uses, benefits, and risks of this tablet during pregnancy.