What Do Pregnancy Tests Test For

Pregnancy Tests Urine And Blood

How do pregnancy tests work? – Tien Nguyen

There are two types of pregnancy tests one uses a urine sample, the other a sample of blood. Both pregnancy tests detect the presence of a hormone called human chorionic gonadotropin . This hormone is produced by the placenta shortly after the embryo attaches to the uterine lining and builds up rapidly in your body in the first few days of pregnancy. It is this rapid shift in hormones that trigger most of your pregnancy symptoms.

How Do Pregnancy Tests Work

When you take a pregnancy test, its looking for the amount of human chorionic gonadotropin in your body. You can find hCG in your urine or blood. However, this chemical needs time to build up in your body, which can cause very early pregnancy tests to come back negative. Each day of early pregnancy, your body will create more hCG. As the weeks go on, youll have more and more hCG in your body, which will make it more likely that a pregnancy test will show as positive.

Pregnancy tests work by reacting to the amount of hCG in either your urine or blood. In a urine test, a piece of reactive paper detects the hCG. This might then show a plus sign, double vertical lines or even the word pregnant. Different tests will show a positive result in unique ways. Read the directions that come with the test to know what a positive result will look like. On the test, there will also be a control window that will show up first. Seeing a symbol in this window will tell you that the test is working. Keep in mind that different brands of tests will take different amounts of time to process.

If you take a blood test, your provider will take a sample of your blood and send it to a lab. The lab will determine the amount of hCG is in your blood.

Second Trimester Prenatal Screening Tests

Second trimester prenatal screening may include several blood tests called multiple markers. These markers provide information about your potential risk of having a baby with certain genetic conditions or birth defects. Screening is usually done by taking a sample of your blood between 15 and 20 weeks of pregnancy . The multiple markers include:

  • AFP screening. Also called maternal serum AFP, this blood test measures the level of AFP in your blood during pregnancy. AFP is a protein normally produced by the fetal liver that is present in the fluid surrounding the fetus . It crosses the placenta and enters your blood. Abnormal levels of AFP may indicate:

  • A miscalculated due date, as the levels vary throughout pregnancy

  • Defects in the abdominal wall of the fetus

  • Down syndrome or other chromosomal abnormalities

  • Open neural tube defects, such as spina bifida

  • Estriol. This is a hormone produced by the placenta. It can be measured in maternal blood or urine to be used to determine fetal health.

  • Inhibin. This is a hormone produced by the placenta.

  • Human chorionic gonadotropin. This is also a hormone produced by the placenta.

  • Abnormal test results of AFP and other markers may mean that additional testing is needed. An ultrasound is used to confirm the milestones of your pregnancy and to check the fetal spine and other body parts for defects. An amniocentesis may be needed for an accurate diagnosis.

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    Best Budget: Clinicalguard Hcg Pregnancy Test Strips

    • Individually sealed, easy to carry around

    • Affordable

    • Not intended for early detection

    If youre trying to conceive and think youll likely go through a lot of tests, ClinicalGuards dip-in strips may be right for you. They come in bulk but are individually sealed, so youll always be prepared. Youll also need a cup for these so you can submerge the strip. If your result is positive, youll see two different color bands pop up.

    Women love that these strips are just as accurate as a stick test but cost way less. Its perfect for anyone who wants to test frequently without wasting money.

    Number of tests: 25 | Display method: Line test | Result time: 5 minutes

    • Wide tip + Floodguard prevent errors

    • Color tip tells you the test is working

    • Less sensitive

    • Blue dye can cause indent lines

    If you are pregnant, you could find out as soon as one minute after taking the test using the Rapid Detection Pregnancy test. The wide, color-changing tip on this manual test makes it easy to use , while the special “FloodGuard” feature helps prevent any user errors. This Clearblue product can be used up to five days before your missed period.

    People who tried this test praise its accuracy and speed of results. They also love that its easy to read so they dont have to wonder about the findings. And quite a few mentioned that it only took a small amount of urine for the test to worka fact that comes in handy if youre trying out multiple tests!

    Early Miscarriage Or Chemical Pregnancy

    What does a positive pregnancy test really look like ...

    You took a pregnancy test and got two lines. But a few days later, your period arrived in force. What gives? The most common reason this happens is an early pregnancy loss, also known as a chemical pregnancy. In this case, the test was accurate there was a pregnancy, but it wasnt a viable one, Dr. Emery explains.

    Its not technically false since a very early pregnancy did occur, he says. But this is the most common reason that a pregnancy test might appear to have been false.

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    History Of Human Chorionic Gonadotropin In Pregnancy Testing

    In 1927 the first bioassay for the diagnosis of pregnancy was introduced . In this test, urine from women in the early stage of pregnancy was injected into immature female mice or rabbits. The ovaries of the animals were examined a few days subsequent to injection for the presence of follicular maturation, luteinisation and haemorrhage into the ovarian stroma, which signified a positive result for the pregnancy test . Following the development of an immunoassay in 1959, the first immunological pregnancy test, the Wide-Gemzelltest, was developed, using rabbit antibodies against hCG . The advent of monoclonal antibodies and the development of enzyme-labelled immunoassays in the 1970s led to more sensitive and accurate hCG assays.

    In the wake of these technological innovations, the company Warner-Chilcott launched the first pregnancy test for home use in 1976. This test was not easy to use it consisted of a test tube and a tube-holder fitted with a special mirror to allow the user to read the results from the bottom of the tube, and it took 2 hours until the results were ready .

    This test operates by using the close relationship between hCG and gestational age. Studies have shown the test results agree well with the results for gestational age calculated using 1113 week ultrasound crown rump length measurements and pregnancy duration calculated by day of ovulation ,.

    When To Seek Medical Help

    Seek immediate medical help if your nausea is accompanied by heart attack symptoms. Heart attack symptoms include crushing chest pain, an intense headache, jaw pain, sweating, or pain in your left arm.

    You should also seek emergency attention if you experience nausea combined with a severe headache, stiff neck, difficulty breathing, or confusion. Seek medical help if you suspect that youve ingested a poisonous substance or if youre dehydrated.

    See your physician if nausea has left you unable to eat or drink for more than 12 hours. You should also see your physician if your nausea doesnt subside within 24 hours of trying over-the-counter interventions.

    Always seek medical attention if youre concerned you may be experiencing a medical emergency.

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    Best Pregnancy Test Subscription

    Price: $$ Pros: The brand is women-owned and has an easy subscription model.Cons: A couple of reviewers commented that the results window was too small.Results time: 5 minutesDisplay method: Line method, with a control window

    Stix joins the ranks of modern womens health brands selling direct to consumers, and they offer the most customizable subscription option for at-home pregnancy tests. Tests come two per pack, and delivery options include every 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks. You can include up to four boxes per shipment .

    The company confirmed these tests are 99 percent accurate on the day of a missed period. Like other over-the-counter tests, Stix tests are HSA/FSA eligible.

    Are There Any Risks With Using A Hcg Pregnancy Test

    How Do Pregnancy Tests Work?

    There are no risks to your health and safety associated with using an hCG pregnancy test.

    However, there is the risk of receiving a false positive or false negative result.

    If you receive a false positive result, this means the test will say you are pregnant even though you are not. This could potentially cause emotional distress after learning from your doctor that a pregnancy has not occurred. To avoid this false sense of hope after receiving a false positive, always wait until you have confirmation from your doctor that you are in fact pregnant before celebrating or telling others outside of your immediate circle.

    If you receive a false negative result, this means the test will say that you are not pregnant even though you are. In this case, a pregnancy may be at risk if you do not take the appropriate care and caution in early pregnancy.

    Whether you are actively trying to conceive or not, if you are having unprotected sex with your partner there is the possibility that you could become pregnant. Regular hCG testing and check-ups with your doctor will help to prevent surprises and set up a potential pregnancy on the right track.

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    How Early Can I Take A Pregnancy Test

    How early you are able to take a pregnancy test will depend on the type of test that you use. All pregnancy tests measure the amount of the pregnancy hormone, human chorionic gonadotrophin in your body. This hormone is produced when the egg is fertilized and attaches to the uterine wall, usually six days after fertilization.

    Some tests are more sensitive than others and can detect very low levels of hCG in your body. The more sensitive tests could detect hCG as early as four days before your missed period. The sensitivity of a pregnancy test can be found on the packaging and is measured in mIU/ml . Sensitivity can range from 10mIU/ml to 40mIU/ml. The lower the number, the more sensitive the test is and, in turn, will detect pregnancy sooner.

    Different Types of Tests

    There are two main types of pregnancy tests, urine test and blood test. Both tests detect the amount of hCG in the body.

    Urine Test

    Urine tests can be purchased at the grocery store or pharmacy and done in the privacy of your home. Results are most accurate when the test is performed when your period is due, or about 2 weeks after you ovulate. However, some can detect pregnancy as early as 4 days before your missed period.

    If you get a positive result, you will want to make an appointment with your doctor to have a blood test done to confirm the pregnancy and begin prenatal care.

    Blood Test

    What Can Cause Pregnancy Tests To Be Wrong

    Each type of pregnancy test is designed to detect a set minimum level of hCG. This is why pregnancy test manufacturers advertise the way they do: Know four days sooner, or Accurate up to six days before a missed period. However, while home pregnancy tests are quite accurate many boast a 99 percent detection rate based on laboratory testing results marketing claims can be misleading. For example, a 99 percent detection rate means a test can detect hCG 99 percent of the time on the day a woman misses her period. These statistics also assume that women are testing at the optimal time, following all instructions, and fully understanding how to interpret the results.

    In reality, its not that easy. Some studies suggest that up to 1 in 4 tests could be misinterpreted, which has led some companies to switch from using the presence of lines or colors to indicate a positive result to using actual words such as yes, no, pregnant, or not pregnant for clarity.

    When a test result is inaccurate, its either a false negative or a false positive . Several factors can cause false negative results:

    Having too dilute urine after drinking a lot of water or testing later in the day.

    Testing too soon when there has not been enough time for an early pregnancy to implant and start producing hCG.

    Using a pregnancy test that doesnt detect lower levels of hCG. You can check the package insert for more information about the level at which the test will be positive.

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    Best Overall Pregnancy Test

    Price: $ Pros: It delivers fast results up to 6 days before your missed period, and has been shown to be the most accurate on the day of your missed period compared to other mainstream brands.Cons: Some reviewers have reported false positives and false negatives, but thats a risk with all at-home pregnancy tests.Results time: 3 minutesDisplay method: Line testIn the largest study of over-the-counter pregnancy tests to date, First Response proved to be 97 percent accurate from the day of your missed period. Easy to find online and in stores, this simple, accurate, and affordable test is by far a user favorite . It comes with three tests per pack, and you can buy a two-pack. In addition to being the most sensitive at-home test, First Response Early Result has an ergonomically designed handle thats easy to hold . You can hold it under your stream urine as you pee no need to pee in a cup and dip. Its also available in a digital format if youre concerned about reading the results correctly.

    What Should I Do After Getting A Positive Pregnancy Test

    What does a positive pregnancy test really look like ...

    If you take a pregnancy test at home and its positive, there are a few things you should do, including:

    • Take your prenatal vitamins pick a vitamin with folic acid included in the ingredient list. Its recommended that you actually start taking these vitamins before becoming pregnant. This is because the folic acid can help prevent birth defects.
    • Make sure to pursue healthy habits. Its recommended that you dont drink alcohol or smoke during pregnancy. You may also want to limit the amount of caffeine you consume each day during pregnancy.

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    Higher Hcg Than Expected

    A higher than normal level of hCG may indicate:

    • Infection or malignant tumors of the uterus
    • More than one fetus
    • Non-cancerous tumors of the uterus
    • Ovarian cancer
    • Sometimes, just an indication of a normal pregnancy, farther along in gestation
    • Testicular cancer

    What The Pros Said

    The consensus from healthcare professionals across the board was that it doesnt really matter what home pregnancy test you use they all work more or less the same way, it just depends on your preferences.

    If thats the case, what does matter when taking a home pregnancy test? They had a few key suggestions:

    • Make sure the test isnt expired.
    • Wait until after youve missed your period to test .
    • Follow the instructions on the box exactly.

    Additionally, there are some key differences that can make one test a better choice for you than another. Weve selected our top home pregnancy test options based on sensitivity, convenience, speed, and cost to help you pick the best pregnancy test for you.

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    Whats Next If The Results Are Negative

    If your test results are negative, but you want to have a baby, keep trying to get pregnant. Also make sure that you begin taking folic acid supplements, if you havent already. You wont always get pregnant from sexual intercourse depending on your menstrual cycle, so use an ovulation calculator or track your cycle on a calendar to decide when the best times are for you to get pregnant.

    Learn more: Ovulation: When am I most fertile? »

    If youve tried to become pregnant multiple times, consider getting a fertility test or asking your partner to get a fertility test. It can reveal whether either of you might have fertility issues that are affecting your ability to get pregnant. If youre infertile, consider other options for becoming pregnant, such as artificial insemination.

    If your test results are negative and you didnt plan to get pregnant, take a second test to make sure the results are accurate. If you took the test because you were concerned that you might have gotten pregnant after unprotected sex, make sure to use any birth control necessary to prevent any future pregnancy scares.

    If your results are negative but youre still experiencing pregnancy symptoms, such as a missed period, see your doctor to find out if another condition is causing your symptoms. Symptoms such as exhaustion, nausea, and vomiting are common to other conditions. Heavy exercise or excessive stress can cause missed periods as well.

    Whats Next If The Results Are Positive

    How Does a Pregnancy Test Work?

    Your next steps depend on two things: whether youre pregnant and whether or not you planned to get pregnant.

    If your test results are positive and youve been planning to have a baby, take another test to make sure youre pregnant. Then, see your doctor before you reach the 8-week mark. You can ask them about prenatal care options or specialists who can help guide you through your pregnancy. Ask your doctor about any changes you need to make to your lifestyle, medications, or diet to keep yourself and your baby healthy for the next nine months.

    If your test results are positive but you didnt plan to get pregnant, ask your doctor about available options, including:

    • carrying the pregnancy to term for adoption
    • what to do if you want to continue your pregnancy

    You can also receive help from a clinic or health center that specializes in reproductive health and child care, like Planned Parenthood.

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