Why negative pregnancy test late period

A very rare cause of a false negative pregnancy test is when the hCG hormone in your body does not react with the anti-hCG chemicals in the test. In this case, you might need to wait a few more days before you can get a positive result or need to have a blood test.

You might ultimately need to have a serum pregnancy blood test or ultrasound to confirm pregnancy. If you still haven't gotten your period after a few more days, try the test again. If subsequent tests continue to show a negative pregnancy test result, you'll want to talk to your healthcare provider about further testing. In rare cases, an ectopic pregnancy can cause a false-negative test result. An ectopic pregnancy is when the embryo implants somewhere other than the uterus.

This usually occurs in the fallopian tubes, but it can also happen elsewhere. An ectopic pregnancy does not develop properly and will not become a viable fetus.

The formation of the placenta is delayed which impedes the production of hCG. An ectopic pregnancy can be dangerous if it causes the fallopian tube to rupture. If your period is late and you are experiencing severe pain, call your provider right away or go to the emergency room.

Ectopic pregnancies are rare, occurring in around 1 in 40 pregnancies. However, they can be fatal. Another rare cause of a false negative test is gestational trophoblastic disease GTD , more commonly known as a molar pregnancy.

GTD is a rare type of tumor that forms from a developing embryo. In less than 1 in cases, a healthy baby can develop from a molar pregnancy. Usually, however, a molar pregnancy ends in miscarriage. GTD causes extremely high levels of hCG. As mentioned above, elevated levels of hCG can throw off an at-home pregnancy test and give a negative result. If pregnancy hormone levels remain high, chemotherapy might be needed. Having one or two irregular cycles a year is not unusual and does not mean there is something wrong.

Reasons your period might be late include:. If excess stress or illness comes just before ovulation, it can throw off your entire cycle. This can make it difficult to know exactly when your period is late. If you recently stopped taking birth control pills , it can also affect your period. Birth control affects your natural cycle and impedes ovulation. After taking hormonal birth control, it can take a few months for your body's hormones to normalize.

While it's less likely, you can get pregnant the first month after stopping birth control. Another possible cause for an off-cycle is fertility treatment. If your cycles are typically short, fertility drugs like Clomid clomiphene may extend your cycle length.

You likely know when you ovulated if you were monitored during treatment. Pregnancy isn't the only reason you might not get your period for an extended length of time. While most people experience menstruation on a fairly regular schedule, for some, irregular timing is the norm. This can make it hard to know when a period is actually late.

You might also miss a period or more altogether amenorrhea. The clinical definition of amenorrhea is not getting your period for three or more cycles in a row.

It may just…. Can you miss a period and not be pregnant? What does it mean? Causes Pregnancy test accuracy When to see a doctor Many people who miss a period will take a test to check for pregnancy. Can you miss a period without being pregnant?

Share on Pinterest A rapid change in weight can cause a lack of estrogen. How accurate are pregnancy tests? Share on Pinterest Taking a test too soon can give a false negative result. When to see a doctor. Exposure to air pollutants may amplify risk for depression in healthy individuals. Costs associated with obesity may account for 3.

Related Coverage. Why do I have two periods in a month? Medically reviewed by Holly Ernst, P. The simple answer is yes, you could still be pregnant even with a negative test, depending on when you took it, but there are also other reasons your period could be late. A pregnancy test detects HCG levels in your urine which increase the longer you are pregnant.

You are most likely to get pregnant about 14 days after the start of your last period — this is the typical time women ovulate in their cycle. It is extremely important to remember that this varies from woman to woman and even from month to month.

Why else could your period be late other than pregnancy? Have additional questions or need to make an appointment? If your home pregnancy test comes back negative after a missed period, wait one week and retest.

Some women may take up to three weeks after a missed period before a detectable level of hCG is produced. A negative result from a home pregnancy test does not unconditionally rule out pregnancy or ectopic pregnancy.

A third reason for a false negative result on a pregnancy test is diluted urine. If you drink a lot of water, it will dilute the hCG in your urine, and could cause you to get a false negative. Test your urine again upon rising in the morning, as this urine will have the most concentrated amounts of hCG.