What if pregnancy test is positive then negative

Modern home pregnancy tests which use a urine sample to detect the presence of human chorionic gonadotropin or hCG, a hormone produced during pregnancy are fairly reliable. So most of the time, getting a negative result on a pregnancy test means that you are probably not pregnant. But there are a few situations in which a false negative can happen. Pregnancy tests will always be more accurate if you wait until your period is late before testing.

Even a test marketed as giving an early answer can give you a false negative if you test before your menstrual period is due. For example, say that you tend to have a typical, day menstrual cycle. You're more likely to get an accurate reading from a pregnancy test if you wait until you haven't had a period for at least 29 days. To be extra safe, you might even consider waiting until day 36, since menstrual cycles in adult women can be anywhere from 21 to 35 days long.

Menstrual cycles in young teens can even be as long as 45 days. When you become pregnant, your level of hCG tends to double every two to three days in the early weeks of gestation. If you test for pregnancy too early, your level of hCG may be so low that it's undetectable by an at-home pregnancy test. If you make a mistake while using the test, such as not using enough urine on the test stick or not waiting long enough to see a result, you may get an incorrect result.

In very early pregnancy, it is possible but not common that drinking a lot of water during the day and testing in the afternoon or evening could affect the accuracy of the test.

When urine is diluted, it can be harder for some pregnancy tests to determine whether hCG is present. However, research suggests that highly sensitive pregnancy tests should stand the challenge of diluted urine.

To be safe, test earlier in the morning to avoid any confusion. If you get a negative pregnancy test after having previously had a positive test result, you may be having a miscarriage —especially if you are also having abdominal cramping and vaginal bleeding and if you notice the loss of any pregnancy symptoms such as fatigue, nausea, and sore breasts.

There is a chance that one of the issues above might be affecting the accuracy of your second pregnancy test if you are still in very early pregnancy. When in doubt, call your doctor's office for advice. If your period is late but your pregnancy test is negative, there are a number of possible explanations. Call your doctor if you believe that you are pregnant. They may perform a blood test, which can detect not just the presence of hCG, but the amount.

Tests that can detect smaller concentrations of hCG in the urine are more likely to show positive results earlier. The levels of hCG are very low in the days immediately before and after the first missed period. Also, these levels can vary from woman to woman in early pregnancy. Some naturally have lower levels than others.

The compounds in home pregnancy tests interact with hCG, and a positive result will often look like a line, a dot, or a plus sign. Most tests also have lines that indicate that the tests are working. In early pregnancy, there may be very little hCG in the urine, and the positive line may be faint. Even a faint positive line has color, and this distinguishes it from an evaporation line, which is colorless.

Any coloration in a positive line indicates that a woman is pregnant. Some pregnancy tests promise to detect pregnancy 5 or more days before a missed period. While they often can, the effectiveness of the test depends on the level of hCG in the urine. According to research published in , the average hCG concentration in urine at 9 days after ovulation — around 5 days before a missed period — is 0.

Because hCG increases so rapidly in the early days of pregnancy, getting the day of ovulation wrong by 1—2 days can affect the result of a pregnancy test. A woman who believes that she is on day 11 can often expect an accurate result, but if she is actually on day 9, the test may not be able to detect pregnancy accurately.

False negatives are more common than false positives. If the result is negative, it may be a good idea to take another test in a few days, to give hCG levels a chance to rise. Very few medications, including fertility drugs, may cause false positives. Otherwise, a positive result followed by a negative result a few days later could mean a very early pregnancy loss. Urine hCG concentrations are often highest when a person wakes up. Taking a test first thing in the morning can increase the chances of an early positive result.

Waiting for the results of a pregnancy test can be agonizing. A simple way to help ensure accuracy is to take two tests. If both show a line, even a faint one, the result is likely positive. Anyone who is unsure of the results should give hCG levels time to rise and take another test in a few days. Getting too much urine on the test stick , since this may affect the results and dilute a positive.

Not correctly reading the test result. Even the faintest positive is still positive. If there is any line visible at all, read the test as positive. Testing at the wrong time. Some women chart their period only by counting days on a calendar.

If your periods are irregular, you might have the dates wrong. Using a pregnancy test that is not sufficiently sensitive. Some pregnancy tests can only detect HCG at very high levels -- levels that only occur several days into pregnancy. Read the test insert to determine how sensitive the test is.

For the earliest possible positive result, pick the most sensitive test. This means selecting the test with the ability to detect very low levels of HCG. To get a positive pregnancy test, many factors have to come into play. Even when a woman is pregnant, she might not get a positive result. To get a positive test, a woman must: Use a sufficiently sensitive test. Test at the right time during her cycle. Test only after implantation. Have HCG levels that are rising.

Correctly read the test, since even a faint positive is still a positive. False positive pregnancy tests are very rare. Most women will never have one. In fact, false positives are so rare that if a woman does have a positive test and later has a negative test, she should assume she had a very early miscarriage.

If you test positive, try testing again a day later. If that test is also positive, then the odds that you are not pregnant are nearly zero. Some reasons a woman might have a false positive include: Allowing a test to sit for too long. This can cause an evaporation line that may look like a faint positive. Using an expired test. This can cause a positive line to appear even if the test is not positive. Having a chemical pregnancy. When this happens, the woman is pregnant, but has an early miscarriage.

A recent miscarriage. HCG levels take a while to drop following a miscarriage. A woman who has recently had a miscarriage may still test positive on a pregnancy test. Taking certain fertility medications.

Talk to a doctor if you take fertility medications, since a home pregnancy test might be less accurate. If you have a positive pregnancy test, call your doctor since you are probably pregnant.

Some women get a negative test, and then later test positive for pregnancy. If this happens, believe the positive test. If one test is positive and one test is negative, the best option is to wait a few days.

Then take a third test. If that test is positive, you are probably pregnant.