Top things to know about taking a pregnancy test when trying to get pregnant:
Urine pregnancy tests are most reliable 1–2 weeks after a missed period
It’s best to take a urine pregnancy test first thing in the morning
It’s important to follow the instructions of the pregnancy test carefully
If you’re trying to conceive, pregnancy tests are likely part of your routine. But how will you know when to take one, and what kind of tests are there?
When should I take a pregnancy test?
If you think you may be pregnant, it’s a good idea to start with a home urine pregnancy test. Waiting to take a pregnancy test can be hard. Each brand of test has its own recommendations on what day to take the test.
For the most reliable results, it’s recommended to take a urine pregnancy test 1 to 2 weeks after your missed period (1).
While it’s possible to get a positive result before your missed period, the chance is relatively small—and the chances of a false-negative are much higher (2). A false-negative result is when you get a negative result even though you’re pregnant (3).
Menstrual cycle length and ovulation date can vary cycle-to-cycle, so it’s easy to miscalculate when your period is due (4). For this reason, 10–20% of pregnant people will receive a false-negative result on the first day of the missed period (1).
If you have an unpredictable menstrual cycle, it can be even trickier to know when to take a urine pregnancy test (1). Tracking the range of your cycle length can be helpful. For example, if your cycles range from 28 to 36 days, you can wait until day 37 has passed to confirm you’ve missed your period. Waiting another 1 to 2 weeks after a missed period will help improve the accuracy of the results (1).
When is the best time of day to take a pregnancy test?
A urine pregnancy test can be taken at any time of the day, but to reduce the chances of a false-negative result it’s best to take it first thing in the morning when the concentration of human chorionic gonadotropin (hCG) hormone in urine would be highest (1).
What kind of pregnancy tests are there?
There are two main types of pregnancy tests: urine and blood tests (5). Both tests work by detecting the presence of hCG (5). Once an embryo implants in the wall of the uterus, the level of hCG begins to rise (5). The level doubles every 37 to 48 hours (5). It’s at its highest in the body at 8 to 12 weeks of pregnancy (5).
Urine pregnancy tests
When used correctly, urine pregnancy tests are reliable (3). Urine pregnancy tests detect hCG in urine when it reaches a certain level, usually between 20–50 IU/L (more on this below) (6). You can take a urine pregnancy test at home, and results take 5 to 10 minutes (6). This kind of test is qualitative, which means results are reported as positive or negative (6). A urine pregnancy test does not tell you how much hCG is in the urine (6).
If you take a urine pregnancy test too soon, the level of hCG in your body may not yet be high enough to detect (3). This means you can get a negative result even though you’re pregnant (3).
Blood pregnancy tests
Your healthcare provider can also perform a blood test (1). This kind of test is quantitative, which means it measures a precise amount of hCG in the blood (6).
A small sample of blood is drawn with a needle and sent to a laboratory (1). The results can take from a few hours to more than a day. Blood pregnancy tests are more expensive and take longer to do than urine pregnancy tests, so they’re not routinely done.
Choosing the right pregnancy test
The most important factor in taking a pregnancy test is following the instructions that come with the test you’ve purchased. Here are some tips when choosing a pregnancy test:
Some home pregnancy tests are more sensitive than others, which means they can detect hCG at a lower amount (7). This information is included in the test box.
The hCG sensitivity level of home pregnancy tests are written in international units per liter (IU/L) or milli-international units per milliliter (mIU/ml). Standard home pregnancy tests have an hCG sensitivity between 6.3 IU/L and 50 IU/L, with most falling between 20 IU/L and 25 IU/L (8). This means a home pregnancy test with a sensitivity of 6.3IU/L will detect a smaller amount of hCG than a test with a sensitivity of 50 IU/L (7). The sensitivity level of a test might also be referred to as the “concentration threshold” on the packaging.
However, be cautious of brands that boast results several days before your expected period (7). Many studies have shown that packaging claims for these products are unrealistic and misleading, and produce a high rate of false-negative results when taken in the days before a missed period (2).
Does format matter?
Pregnancy tests come in different formats, and some instructions are easier to understand than others (9,10). Choose the test that is most convenient for you.
For midstream tests, you must hold the absorbent side of the test under your urine stream (3). For others you may have to collect your urine in a container and dip a testing strip in your sample, or a dropper may be provided to place a small sample onto a testing area (3). Choosing one format over the other is a matter of personal preference, but it’s important to follow the specific instructions closely (10).
You may conceive on your first try, but for some it may take up to 12 months or longer (11). Since the number of tests you’ll ultimately need is unknown, cost can be an important factor when deciding which test to purchase. If testing frequently, it might be a good idea to purchase less expensive strip tests. In some countries, strip tests may only be available for purchase online (10). In the USA for example, you may be able to purchase pregnancy tests at a dollar store or discount store.
Clarity of results
Pregnancy tests can display the results in a number of different ways. A positive result could be indicated with two lines, a plus sign, or the words “yes” or “pregnant”—check the instructions of your test.
On midstream visual pregnancy tests, the first line of the test is the control line that shows that the test worked (3). The appearance of a second line indicates that the result is positive (3). Sometimes, the second line may be hard to see or faint, which can be easy to misread (3,12). Newer digital tests display the result in words: as “pregnant” or “not pregnant” (12,13).
What to do if your pregnancy test is negative and you still haven’t had your period
If your urine pregnancy test result is negative, and you still haven’t had your period, it’s possible that you took the test too early and the level of hCG may not be high enough to detect (2). You can take another pregnancy test a few days later (1).
A false-negative result can also occur if the urine sample is diluted, usually from drinking water throughout the day (14). If you suspect you are pregnant, you can take another test first thing in the morning when your urine is more concentrated (14).
If you do a home pregnancy test, get a negative result, and you still haven’t had your period after a week, then it’s a good idea to follow up with a healthcare provider for another test.
Seek advice from your healthcare provider if you are unsure of your test result. A blood test may be done to get a more precise count of your hCG levels (1). Your medical history, physical examination, and other tests can help your healthcare provider give you a more reliable result (1).
Even if your pregnancy test is negative, it’s important to listen to your intuition when it comes to your body. Speak to a healthcare provider if you have any concerns about your health or menstrual cycle.
What to do if your pregnancy test is positive
If you were trying to conceive and have a positive result; congratulations! Here are a few things to do now:
Call your healthcare provider to book a prenatal appointment. You might have to wait several weeks for this appointment, but you may be seen early if you have a history of previous miscarriage, or a chronic condition like diabetes or hypothyroidism. Be sure to mention this to the person making your appointment. During this appointment, your healthcare provider may confirm the pregnancy with another pregnancy test and calculate your estimated due date (15).
Take a prenatal vitamin with folic acid. It’s recommended to start taking folic acid before becoming pregnant to help reduce the risk of neural tube defects, a birth defect to the brain and spine (15).
Take care of yourself. Pregnancy creates extra demands on the body (16). Eating a diet rich in fruits and vegetables will help you get the key vitamins and minerals needed to support the growth of the fetus as the pregnancy progresses (16).
Some people may have a hard time coping with the challenges of early pregnancy. High levels of stress can create physical changes in the body that can have a negative impact on your health and pregnancy (17). Learn to manage stress in whatever way works for you. This may include taking some time for yourself, doing something enjoyable, or seeking out support. Pay attention to how your body feels. It’s okay to say no to work or social plans if you need to.
Is it possible to get a false-positive pregnancy test result?
Yes, but this is rare (18). After a positive pregnancy test you should book a follow-up with your healthcare provider (15).
If you’ve had a positive result followed by a negative result a few days later, it could be indicative of a chemical pregnancy. This is not a false-positive: it is a very early pregnancy loss soon after implantation (19). Chemical pregnancies are common and are estimated to account for between 8% and 33% of all pregnancies (20). An accurate number is difficult to determine since most chemical pregnancies occur before a person even realizes they are pregnant (19).
If you are using assisted reproductive technologies to conceive, or have received an injection of hCG, be sure to take a home pregnancy test on the day your healthcare provider advises, as taking it too early may result in a false-positive (21).
Whatever the pregnancy test result, you’re not alone
When you are trying to conceive, taking a pregnancy test can be an exciting moment. For the most reliable results, you should take a pregnancy test 1–2 weeks after your missed period, using the first urine of the day. However, it’s understandable if you’re tempted to test earlier. Waiting the appropriate amount of time will reduce your risk of a false-negative result and potentially save you some heartache. If you’re unsure of your test result, you can take another test a few days later. Whether your test is positive, negative, or uncertain, you should seek advice from your healthcare provider if you believe you might be pregnant.