| Pregnancy Tests |
| Written by Samuel Blue | |
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Pregnancy test is an attempt made to find out whether the woman is pregnant or not. With the advancement in technology and science there are some pregnancy tests that even look for the chemical markers that are associated with pregnancy. These markers are normally found in the blood and urine and the pregnancy tests require a sample of any of these substances to gain accurate results. The blood markets or human chorionic gonadotropin (hCG0 was actually discovered in 1930 which is produced by the trophoblast cells that are present in the fertilized ovum or the blastocyst. Although hCG is a reliable indicator for pregnancy it still cannot be detected until after the implantation. However it could result in false negatives when the test is performed during early stages of pregnancy. Moreover obstetric ultrasonography is also being used widely to detect pregnancy in women. This obstetric untrasonography had been first practiced during the 1960s but the first test kit test for hCG had been released during the mid 1970s. Pregnancy calculator should be discovered.
Pregnancy test which is designed to provide the fastest results after fertilization is called as the rosette inhibition assay and is meant for early pregnancy factors. Some early signs of pregnancy can be found in the blood after the 48 hours of fertilization. Unfortunately, conducting tests for early pregnancy factors could be time consuming and even expensive. There are some pregnancy tests that generally look for the presence of beta subunit of the human chorionic gonadotropin or hCG in the urine or blood. This hCG could be detected in the blood or urine after the implantation that generally occurs after 6 to 12 days of fertilization. The serum beta or quantitative blood tests could also detect the hCG levels even when they are 1 mIU/mL lower but the urine tests hae published the detection of threshold of nearly 20 mIU.mL based on the brand used. The qualitative blood test might normally have a threshold of around 25 mIU.mL, which makes them less sensitive compared to other available home pregnancy test methods. Moreover some of the home pregnancy test methods even depend on the lateral flow technology. However with gestational sac and obstetric ultrasonography can sometimes be visualized as early as half weeks of gestation while at about five week’s of gestation for the yolk sac. Additionally the embryo might also be observed or measured by nearly five weeks. Moreover the heartbeat might also be observed after around six weeks and is generally visible after several week’s of gestation. The accuracy in pregnancy testsAccording to a systematic review that was conducted on home pregnancy tests shows that when they are used by the experienced technicians can actually get the most accurate results which are similar to professional laboratory testing. However when they are used by general consumers the accuracy level could actually fall below 75 percent while the review also states that most of the users also misunderstood or eve failed to follow proper instruction that are included in home pregnancy test kits. Moreover improper usage of the kit might also cause both false positives and false negatives.The false negative readings might generally occur when pregnancy testing is conducted too early. The quantitative blood tests along with the most sensitive urine pregnancy test generally detect hCG soon after implantation and this can occur anywhere from six to twelve days of ovulation. However some less sensitive urine tests along with qualitative blood test might also not detect pregnancy results until 3 or 4 days after the implantation. The menstruation might usually occur on the 14th day after ovulation and so the probability of false negative would be low in case the menstrual period is found to be late. The ovulation might not occur at predictable time during a normal menstrual cycle. There are a number of actors that might cause unexpectedly late or early ovulation and even with women with history of regular menstrual period cycle. Therefore using ovulation predictor kits or even charting your fertility signs of basal body temperature or cervical mucus might give you more accurate ideas of when you can conduct the test rather than just counting days. The pregnancy test accuracy could be most closely related during the ovulation day and not the act of insemination or intercourse which caused pregnancy. Moreover it is also normal for sperms to live up to 5 days in the fallopian tubes as they wait for ovulation to occur. Therefore it might take more than 12 days for implantation to take place which means even the best pregnancy test might give you false negatives until the 17th day after the act which caused pregnancy. As some pregnancy test generally have high hCG detection it might also take 3 to 4 additional days for hCG to get high to a level that is detectable by these home pregnancy tests which means that false negative might still occur up to 3 to 4 weeks after intercourse which caused pregnancy. Pregnancy calculator is another topic. |
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