how long does it take for a pregnancy test to work

When you're waiting on the results of a pregnancy test, minutes tin can feel similar hours. Test likewise early on, nevertheless, and yous risk the adventure of an inaccurate result. To assist ensure your test accuracy, there are some guidelines you should follow—like knowing where yous are in your menstrual bicycle or when you concluding ovulated.

Hither's everything you lot demand to know most pregnancy tests, including how they work, when to accept ane for the well-nigh accurate issue and symptoms that could betoken information technology'southward fourth dimension to accept a exam.

How a Pregnancy Test Works

Pregnancy tests detect human chorionic gonadotropin (HCG), commonly known as "the pregnancy hormone." This hormone is generated from the placenta, an organ that connects the fetus to the mother. It begins to form and protect the egg in one case information technology's implanted along the uterine wall, signaling pregnancy has begun. At first, HCG levels are low, simply they increase at the beginning of the pregnancy earlier leveling off.

As HCG levels increase—frequently doubling every three days until reaching their superlative within the get-go 8 to 11 weeks of pregnancy—they can be detected in both blood tests (conducted at a physician'due south office) and urine tests (almost often taken at habitation).

At that place are three types of at-home tests: strip, cassette and midstream. Strip tests crave y'all to urinate into a cup and place the test strip directly into the urine. Cassette tests require you to urinate into a cup and so place drops of urine directly onto the examination stick. Finally, midstream tests crave yous to urinate straight onto the test stick.

Your HCG levels must reach 25 milliInternational units (mIU) per millimeter (mL) to bespeak a positive result—which frequently happens within 3 to 5 weeks after your last menstrual cycle. At-domicile pregnancy tests find these HCG levels and most often reveal lines or a reading of "Pregnant" to indicate a positive upshot, depending on the type of test you lot accept.

"Most dwelling (urine) pregnancy tests discover HCG levels of 20 (mIU) or greater," says Kelly Culwell, M.D.—known professionally as "Dr. Lady Doctor"—a board-certified OB-GYN and a previous medical officer for the World Health Organization in Geneva, Switzerland. "Blood tests detect HCG levels of 2 (mIU) or greater, so a blood test might be positive before a urine test is."

While a typical urine test volition show positive results at about twenty to 25 mIU, it'south dependent on your urine concentration—the less diluted the urine, the higher the concentration of HCG. Since urine is more than full-bodied in the morn, a examination taken then is more probable to produce a positive upshot than ane taken afterwards in the day. Nonetheless, most urine tests will be positive by one to two days after a missed catamenia.

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When You Should Take A Pregnancy Test

You should wait to accept a pregnancy examination until the commencement twenty-four hour period of your missed period. Since HCG is but present once implantation of the egg occurs, there often isn't plenty of the hormone to be detected until yous miss your menstrual wheel.

"Pregnancy tests pick up the hormone secreted after implantation, which commonly occurs about two weeks after the sperm meets the egg," says Dr. Culwell. "For women who have regular periods, this usually means that HCG can be detected as shortly as you miss a menses."

This, of course, assumes you have a regular menstrual cycle that can exist easily tracked and predicted. If this isn't the case, you may cull to instead rail ovulation, or when an egg is released and makes its manner to the uterus where information technology can potentially be fertilized. An at-home ovulation predictor kit can assist y'all rail fertilization.

If this method is used, information technology's best to have a pregnancy exam "approximately xiv days after a documented ovulation," says Zaher Merhi, M.D., an OB-GYN, reproductive endocrinologist and founder of Rejuvenating Fertility Center with locations in New York and Connecticut.

Symptoms Signaling It's Time to Accept a Test

The biggest indicator it's fourth dimension to have a pregnancy test is a missed period. It isn't the only sign, even so. Symptoms that signal information technology may be fourth dimension to accept a pregnancy exam, according to Dr. Merhi, include:

Missing a menses
Breast fullness/soreness
Frequent urination
Nausea
Vomiting
Fatigue
Abdominal bloating

When Is the Best Time to Take a Pregnancy Examination?

You lot can have a pregnancy test any fourth dimension of the twenty-four hours. But if there'south a chance you lot're early on in pregnancy, accept it in the morning when your urine is well-nigh concentrated so the test can more easily detect the HCG hormone, says Dr. Culwell.

"The best time in the bike to take a test would exist after you have missed a flow," says Dr. Culwell. "This will make information technology less likely that you might miss an early pregnancy if the HCG levels are too low to be picked up by the test."

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How Presently Tin You lot Take a Pregnancy Test?

At-home pregnancy tests are regulated by the Nutrient and Drug Administration (FDA), pregnant their accuracy and labeling is evaluated before they achieve store shelves. When it comes to the accuracy of at-dwelling house pregnancy tests, research shows if the examination is used as directed, an inaccurate issue is rare. While false-positive pregnancy examination results are uncommon, if you lot practise receive an inaccurate issue, it'southward more probable to exist a faux-negative. In this example, information technology'south probable you're testing besides early on, earlier HCG tin can be detected.

"For most women who have a regular menstrual bicycle, a pregnancy test could be taken on the expected twenty-four hours of the period," says Dr. Merhi. "The earliest [fourth dimension to exam] would be the expected solar day of the period; however, I usually tell patients to look at least a few days (or one week) after the expected day of the period in order to lower the chances of having a false outcome."

It's worth noting that at-home pregnancy tests accuracy claims—many of which annunciate an accurateness rate of 99% from the day of the expected menses—are based on data used in a sterile laboratory testing environment. If you lot think you received an inaccurate result, you can either wait and examination over again a few days later or see your doc for a blood examination, which can detect HCG earlier than at-home tests and has an accuracy rate of 99%.

When You lot Should Get a Pregnancy Claret Test

A pregnancy blood test at your doctor'south part is another way to ostend a pregnancy.

"The claret test can find the pregnancy earlier than an at-home urine test; eight days after ovulation is the earliest a blood test could find a pregnancy," says Dr. Merhi.

Should you receive a positive at-home pregnancy examination outcome, your doctor will ofttimes perform an in-office blood test to confirm the presence of HCG. This and additional blood tests as well provide additional information about your health and the health of your pregnancy.

"Blood tests are also needed to check for complications of pregnancy—for instance, if you are at take a chance for ectopic pregnancy [pregnancy implanting outside of the uterus], miscarriage or an abnormally progressing pregnancy," says Dr. Culwell. "[This is] because they can measure out whether your pregnancy hormone levels are progressing usually or decreasing."

Should yous experience a miscarriage, HCG tin can remain in your body for a few weeks, and additional tests taken in the weeks following can lead to a false-positive upshot, says Dr. Merhi.