It's important to schedule your Pregnancy Test when needed with your primary OB-GYN

The purpose of the pregnancy test is to find out whether a woman may or may not be pregnant. Pregnancy tests look for chemical markers that suggest that a new pregnancy is in progress. These markers are among the first, early signs of pregnancy and can be found in a woman's blood and urine. Pregnancy tests involve testing a sample of one of these substances.

The very first chemical marker for pregnancy ever discovered was human chorionic gonadotropin (hCG). This marker was discovered in 1930 and is a good reliable marker for pregnancy.

However, since hCG is not formed until after implantation has taken place, a woman who gets a negative result in what may be a very new pregnancy should retest in a week or two. The very first home pregnancy test kit using hCG levels as a indication of pregnancy was placed on the market during the mid-70's.

Women's Health

Yet another way to detect a pregnancy is through an obstetric ultrasound test; a discovery that has had a major impact on women's health. This type of ultrasound testing was first used during the 1960's.

The ultrasound enables a technician to view the gestational sac at a month and a half after gestation or two and a half weeks after a woman has ovulated. The yolk sac can be seen two weeks later. In just a few more days, the embryo can be seen and measured. Half a week later the heartbeat can be observed.

It's easy to see how the ultrasound test has become such an important tool for spotting the early signs of pregnancy. The obstetric ultrasound offers the physician a window into fetal development through which he can witness the progression of a healthy pregnancy.

Fetal Development

But the ultrasound may also be used to spot problems. For instance, if the heart rate is lower than expected, or the fetus misses a milestone for fetal development, there may be a problem with the pregnancy. However, the final diagnosis should not be based on only one ultrasound scan. The interpretation of a scan is based in part on the estimated age of the fetus. If the estimate is off, there can be a negative result. For this reason, when a problem is spotted on an ultrasound scan, the test should be repeated in 7-10 days later.

As for home pregnancy test kits, a review that was published in 1998 suggested that these kits are about as accurate as professional lab tests with a rate of accuracy of 97.4%. But when consumers use these kits, the accuracy rate falls to 75%.

The authors of the review discovered that many consumers fail to follow the package instructions and some misunderstand the correct use of the kits. The incorrect use of the home pregnancy test kit can cause false negatives as well as false positives.

Knowing you have conceived at the earliest possible time is one way to ensure a healthy pregnancy. Many women change their lifestyle habits for the sake of a pregnancy only after they have conceived. By the time a woman discovers early signs of pregnancy her habits may have already caused damage to her baby.

Women who have had fertility treatments may be considered high risk pregnancies should they manage to conceive. A doctor needs to know at the earliest possible moment that such a patient has conceived in order to take measures to ensure a healthy pregnancy. With today's burgeoning rates for couples having fertility issues, monitoring women for conception has become a major women's health issue.

By the time a woman shows early pregnancy symptoms, it may be too late to take the necessary steps to preserve her health and that of her fetus. For these women, it is imperative not to wait for early pregnancy symptoms before being tested for pregnancy.

On the other hand, if a woman tests too early, it's all too possible to generate a false negative result. Most blood tests and urine tests detect hCG only just after implantation. 

Implantation occurs from 6-12 days after conception. The less sensitive blood and urine tests won't detect that conception has taken place until 3-4 days after implantation takes place. Because of this, the optimal time to use these tests is when you discover your menstrual period is late. Menstruation comes on average 14 days after ovulation has taken place. Once you miss your period, you've passed the time period in which a false negative reading might occur.

However, it's important to note that ovulation is not always predictable. There are a variety of factors that may hasten or postpone ovulation even in women who have a menstrual history of regular cycles.

Because of this, the use of ovulation predictor kits (OPK's), charting cervical mucus, or the basal body temperature, may give a better idea of when a woman can expect to accurately test for pregnancy as opposed to the method of counting days.