Home pregnancy tests: Useful products with some drawbacks
Are you feeling nauseated or fatigued? Is your period late? If so, taking a home pregnancy test may be a reasonable next step.
Whether it's your first time or your fifth time, taking a home pregnancy test (HPT) can be nerve-racking. To quell your anxiety, find out how HPTs work, what can affect the results and when to visit the doctor.
How HPTs detect pregnancy
As soon as a fertilized egg is implanted in your uterus, your body starts releasing a hormone called human chorionic gonadotropin (HCG) into your bloodstream. Your blood and urine contain HCG throughout pregnancy. If a test detects HCG in your blood or urine, it almost always means you're pregnant.
All HPTs check for HCG in the urine instead of the blood. The tests come in these three types:
* The dipstick test. This type of HPT requires that you either place the end of the dipstick in your urine stream as you urinate or immerse the dipstick in a container of collected urine for five to ten seconds. A minute or two later, the result will appear on the strip as a symbol (such as a plus or minus sign), a line, a color change or even the words pregnant or not pregnant.
* The collection cup test. For this test, you need a sample of urine collected midstream — a few seconds after you've started to urinate. When you have the sample, you take some of the urine into an eyedropper and squeeze five or six drops on a test disc provided in the HPT kit. The urine makes the disc change to a particular color if you are pregnant and to a different color if you aren't.
* The chemical mixing test. In this test, you place a small amount of urine in a test tube with a liquid or powder chemical mixture. If the chemicals make the urine change color, it means you're pregnant.
Grocery stores and drugstores carry a wide variety of HPT kits. They're quick, easy to use and fairly inexpensive, with prices ranging from $7.99 to $19.99.
Most HPTs claim to be 97 percent to 99 percent accurate if they're used correctly. Instructions are slightly different from kit to kit, so read through them carefully before you start. Then, for the most accurate result, follow the instructions closely.
Results can be incorrect
Although HPTs are generally reliable, you have to use them properly. Otherwise, you may get a false-positive or false-negative result. Possible causes of false-positives include:
* Using an unclean urine collection cup. If your HPT uses a cup, be sure that it's clean and free of any soap residue. Detergent buildup on the cup may cause a false-positive result.
* Using an old or damaged kit. Be sure to check the expiration date on the box before taking the test. Also, a kit that has been exposed to heat, dampness or vibration may have a false-positive result.
* Having an impure urine sample. Blood in your urine — from a urinary tract infection, for example — may lead to a false-positive result, as may protein, which sometimes gets into the urine if you have kidney damage. Certain rare tumors may also secrete HCG and cause a false-positive result.
* Taking certain prescription drugs. Certain medications such as anticonvulsants, anti-Parkinson drugs and tranquilizers may cause false-positive results. Also, diuretics (often used to treat high blood pressure) and promethazine (used to treat allergy symptoms and nausea) may trigger a false-positive result.
You may get a false-negative result from:
* Taking the test too early. Taking a pregnancy test too early may give you a negative result when you actually are pregnant. Hold off on the HPT until your period is at least one day late.That's the earliest an HPT can possibly detect pregnancy — in fact, most HPTs are unreliable until your period is a week late. The bottom line: If you have a negative HPT on the day after your period was due, wait a week. Then, if your period hasn't started, repeat the test.
* Timing the test wrong. Perform the test within 15 minutes of collecting the urine sample. After you start the test, be sure to give it time to work, but don't wait longer than the instructions tell you to. If you tend to lose track of minutes, use a timer or a clock.
* Using diluted urine. Consuming large amounts of fluid before taking an HPT may also cause a false-negative test result. It's best to take an HPT first thing in the morning because that's when your urine is the most concentrated.
If you have any questions about how to perform the test or interpret the results, look in the instructions for a toll-free help number to call. Also, since many pregnancy tests come in packages of two, don't hesitate to take a second test if your first test results are unclear.
When to contact the doctor
As soon as you find out you're pregnant, it's time to make an appointment with your doctor or nurse practitioner to begin your prenatal care. At this point, your doctor or nurse may follow up with a blood test and pelvic exam to confirm your pregnancy. Blood tests can detect HCG as early as six to eight days after conception (when the egg is fertilized).
A blood test can also quantify the level of HCG in your blood, providing clues to the progress of your pregnancy. In typical pregnancies, HCG levels increase dramatically during the first trimester and decrease somewhat thereafter. An abnormal HCG level might be a sign of a problem, such as miscarriage or tubal pregnancy, or it might mean you are carrying more than one baby. If you have abnormal HCG levels, your doctor will address them and monitor you closely during your pregnancy. Unless there are other signs to cause concern, the HCG test is usually not performed more than once.
You should also talk to your doctor if you miss your period for more than two months and you're not pregnant. Pregnancy is not the only possible cause of irregular menstruation. Women using birth control pills, for example, often miss periods and think, incorrectly, that their contraceptive method has failed them. If you get a negative result on an HPT after missing a period while you're on the pill, continue to take it as directed. Talk to your doctor before discontinuing the pill if you're repeatedly missing periods.
Other things that can make you miss periods include:
* Breast-feeding
* Certain medications
* A serious illness
* Malnutrition or obesity
* Extreme exercise regimens
* Stress
* The onset of menopause
By talking with you about your lifestyle and health, your doctor will be able to recommend ways to get your menstrual cycle back on track.
http://www.mayoclinic.com/health/home-pregnancy-tests/PR00100
2006-11-02 10:39:19
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answer #2
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answered by Janny 6
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VERY unlikely you are pregnant. Whatever age you are, if you are really 3 and 1/2 months late it will show up, believe me!
I think you have not ovulated and you will not get a period unless you have ovulated. You get a period 12-16 days after ovulation. Please go see your doctor and ask to be put on a drug that will start your period (they'll know what you're talking about). Don't let the doc fob you off - ask questions and demand answers!
Please use a condom next time so you won't have this worry.
2006-11-02 10:28:37
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answer #3
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answered by yoyo 1
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