Show
What Are Pregnancy Tests?
In 6 to 12 days after conception, a woman may experience implantation bleeding. About 7 days after that, hormone levels in the urine are high enough to detect using a home pregnancy test. In general, take the test after you notice your menstrual period is late. Pregnancy tests are used to verify if a woman is pregnant. They work by checking urine or blood for a hormone called human chorionic gonadotropin (HCG) that the body produces when pregnancy occurs. This hormone is released when a fertilized egg attaches to the lining of the uterus, signaling the beginning of pregnancy. What Do Pregnancy Test Results Mean?If pregnancy test results are positive, it means a woman is pregnant. If they’re negative, it means a woman is not pregnant. When Can A Pregnancy Test Be Taken?Pregnancy tests may be taken any time after a woman’s menstrual period is late. A woman may also choose to test after implantation bleeding has occurred. Implantation bleeding is an early sign of pregnancy. It occurs when a 6 to 12-day-old fertilized egg attaches to the inner lining of the uterus, causing light vaginal bleeding or spotting. About one-third of women experience implantation bleeding, which is normal and typically happens near the time of a woman’s next expected menstrual period. About four to five days after implantation bleeding, HCG levels in the body reach detectable levels in the blood. For at-home urine pregnancy tests, it may take up to 7 days for HCG levels in the urine to reach detectable levels for testing. How Soon Will A Pregnancy Test Read Positive?While some pregnancy tests claim to work a few days before a missed period, the results are usually less accurate at that point. Some tests may be able to detect pregnancy hormones in urine as early as 10 days following unprotected sex, but the results are not very reliable, and women may get a false positive or false negative test result. For women who have irregular periods or who do not get periods at all, testing about 3 weeks after unprotected sex may yield more reliable results. If a test reads positive, a woman may want to check with her doctor for a blood pregnancy test to confirm the results. Most women who have a positive pregnancy test should wait a week or two before calling the doctor for a blood test. Why Might A Pregnancy Test Produce the Wrong Result?There are 2 types of inaccurate results:
There are several reasons for inaccurate results:
SLIDESHOWStages of Pregnancy: Week by Week See SlideshowReferences Medscape Medical Reference Are you experiencing some spotting and wondering whether it’s an implantation bleed? Maybe your period is a day or so late and you think you may be pregnant? Are you considering how soon to do a pregnancy test after implantation? When you’re trying to become pregnant, the temptation might be to do a pregnancy test earlier than you should. This can often lead to false results and disappointment. Playing the waiting game is hard, but there are good reasons for holding off that test for a couple of days. Let’s look at what a pregnancy test detects and how soon after implantation this could be done. What Is Implantation?Following fertilization, the egg travels down the fallopian tube to the uterus. The uterine lining, or endometrium, is ready to accept the fertilized egg. This journey usually takes about six to eight days to happen. On reaching the waiting uterus, the egg attaches itself and then burrows its way into the lining, preparing to grow. This implantation takes a few days to complete and can sometimes cause a slight bleed (1). Is It an Implantation Bleed or a Period?It’s important to note that not all women will experience signs like bleeding or cramps indicating implantation has happened. Every woman and every pregnancy is different. There are a few things you can look out for to distinguish between an implantation bleed and a normal period (2).
What Happens After Implantation?Let’s explore what happens with hormones after the ovary releases an egg. During a woman’s monthly cycle, an egg leaves the ovary and the shell that contained the egg remains, called the corpus luteum. This is responsible for releasing the hormones estrogen and progesterone. It’s the progesterone that we’re interested in here, as it signals that the lining of the uterus to prepare itself to receive a fertilized egg. If the egg does not implant, the progesterone levels drop again and the uterine lining comes away, resulting in your monthly bleed roughly two weeks after ovulation. If implantation happens, then the uterus needs to signal the corpus luteum to continue producing progesterone to maintain the uterine lining. This is done by the newly forming placenta releasing a hormone called “human chorionic gonadotropin” or hCG. All women have small traces of hCG in their bodies at all times, but after implantation, these levels rise and it is this hormone that is tested to indicate a pregnancy. The amount of hCG normally found in the body won’t be enough to give a positive test. However, during the first eight weeks of pregnancy, hCG levels double every couple of days (3). So while the waiting game might not be an easy one, just a few days can make a difference between a positive and negative test. Methods of Pregnancy TestingThere are two ways of testing for hCG levels, either via urine or blood. 1. Urine Tests for hCGHome pregnancy tests have improved over the years and are now sensitive enough to detect small amounts of hCG in your urine. The sensitivity of the test is indicated on the packaging as an amount in mlU/ml (milli-international unit per milliliter). The lower the number of mlU/ml, the more sensitive the testing kit is. The range is usually between 10mIU/ml and 50 mIU/ml. Some of these tests might pick up enough hCG as soon as four days before your period is due. This is between six and eight days after ovulation and conception (4). However, that is unusual and it generally takes about 10 or more days after ovulation for a test to show a positive result. Even using the most sensitive of these tests, there might not be enough hCG to be detected yet. This can result in a false negative test which may be upsetting. If you do have a negative test, wait a few days and test again. Your urine hormone levels might have risen enough for the test to detect. 2. Blood Tests for hCGhCG is found in your blood a lot sooner than in urine. A positive test might be detected as soon as six to eight days after conception. You would need to visit your doctor to have a blood test, but they will likely advise you to wait till after your missed period. Even if you do a home pregnancy test and get a positive result, your doctor may still do a blood test to confirm this. There is no definitive time for when you should take a pregnancy test after implantation. While you can take a test as soon as the first day of your missed period, it might be better to wait a week more. Many factors come into play as to how accurate the result might be. You might have conceived at the beginning of ovulation. In this case, you will likely get a positive test earlier than if you conceived at the end of ovulation. You might not know that implantation has taken place. Not all women experience an implantation bleed or any other symptoms indicating that it has taken place. There are also times when a negative test might happen even if you are convinced you have had an implantation bleed. These include ectopic pregnancies and tumors.
Editor's Note: Caitlin Goodwin, MSN, RN, CNM What looks like an implantation bleed is sometimes unrelated luteal phase spotting caused by a second surge of estrogen. Many women experience this completely normal spotting without being pregnant, and many women become pregnant and never experience any implantation bleeding. There are other signs of early pregnancy that might prompt you to take a pregnancy test. These include tiredness, nausea, tender breasts, and, above all, a missed period. False Negative Pregnancy TestsWhen you’re trying to get pregnant, the urge to do a test can be hard to resist. If you take a test and get a negative result, you could still be pregnant. Some reasons you might get a negative result are (6):
Wait a few days and test again, particularly if you tested before or soon after a missed period. If you feel you are pregnant and are still getting negative test results or still don’t get a period after a week, then see your doctor. The doctor will probably do a blood test or an ultrasound scan to confirm a pregnancy or help discover the cause of your missed period. To Test or Not to TestMany pregnancy tests claim to be accurate from the first day of your missed period, or even earlier. This might not always be the case and you only put yourself through the unnecessary upset that comes with a negative test. Everyone differs in how quickly or how much hCG they produce after implantation, so now is the time to practice patience Try and resist peeing on that stick, even though the little devil on your shoulder will be whispering in your ear, “do it.” Feedback: Was This Article Helpful? Thank You For Your Feedback! Thank You For Your Feedback! How long does implantation bleeding last before positive pregnancy test?Implantation bleeding is generally light and short, just a few days' worth. It usually occurs 10-14 days after conception, or around the time of your missed period. However, vaginal bleeding has been reported anytime in the first eight weeks of pregnancy.
Can you test negative for pregnancy before implantation bleeding?Often, taking a pregnancy test before the missed period or during implantation bleeding is just too soon for tests to offer conclusive results. Ideally, waiting a week after the spotting or missed period is most desirable as the results should prove more accurate.
Should I take a pregnancy test before or after implantation bleeding?The easiest way to find out is to wait a few days and then take a home pregnancy test. These tests work best a few days after implantation bleeding has stopped.
|