In vitro fertilization (IVF) has helped many women conceive. It is often an effective method for dealing with a variety of fertility issues, whether you use donor eggs or your own. However, once the IVF treatment is completed, most women want to know immediately whether or not they are pregnant.
Unfortunately, you cannot get instant results. You need to wait to see if the embryo transfer was successful. While you may be pregnant, it can take up to two weeks for the placenta to begin producing enough hCG hormones for detection by a pregnancy test.
After the embryo transfer, you may wait at the clinic for several hours before the doctor sends you home. Fertility specialists often schedule a follow-up appointment in two weeks for a blood pregnancy test. However, if you cannot wait that long, you may be tempted to take an over-the-counter pregnancy test.
How accurate are over-the-counter pregnancy tests? If you take one too early, it may not be accurate at all. You run the risk of getting a false negative result, which means that the pregnancy test did not detect enough of the hormone in your urine to indicate that you are truly pregnant. However, this does not mean that you are not pregnant.
If you want to understand the importance of waiting for your doctor to perform a blood pregnancy test, you need to know how the hCG hormones work.
What Are Human Chorionic Gonadotropin Hormones?
The human chorionic gonadotropin (hCG) hormones are often called pregnancy hormones. After successful fertilization, the developing placenta begins to produce these hormones.
The first few days after fertilization, hCG levels are often very low. A little over a week after conception, these levels should be high enough for detection by a blood pregnancy test. However, there is still a risk that the test will not produce an accurate result.
With a home pregnancy test, the hormones are typically undetectable until two weeks after conception. The same problem occurs when the home pregnancy test is taken too early. The results may not be accurate.
After the two-week period, hCG levels begin to double every three days. They quickly climb and then peak about 8 to 11 weeks into your pregnancy.
The hCG hormones are measured in milli-international units per milliliter. Levels that are less than 5 mIU/ml indicate that you are not pregnant. Levels above 25 mIU/ml indicate that you may be pregnant. Anything below 25 may not be detected by a home pregnancy testing strip.
Over-the-Counter Pregnancy Tests Are Not Always Accurate
The most accurate home pregnancy tests claim to provide 99.9% accuracy in detecting whether or not you are pregnant. However, this claim can be misleading.
Over-the-counter pregnancy testing kits have been available in the United States since the 1970s. While these tests have improved over the years, they are not always 99.9% accurate. In fact, one study found that these tests tend to have an overall accuracy of 75%. However, this lower accuracy is partially due to user error.
Most home pregnancy tests use the same method to detect pregnancy. You urinate on the testing stick and wait for a little line to appear. Unfortunately, there are many things that can go wrong during this testing process that may result in a false negative result.
If you do not urinate on the stick for the recommended amount of time, the testing strip may not receive enough saturation from the urine to accurately detect the hCG hormones. You may also receive a defective test strip.
Another common reason for a negative result is using stored urine. The urine needs to be at a specific temperature to ensure that the test is accurate. If you use urine that you have stored in the fridge, there is less chance of an accurate result.
While these issues may limit the accuracy of the home pregnancy test, the most common reason for a false negative is taking the test too early. As mentioned, you need to wait until the placenta is producing enough pregnancy hormones for detection by the pregnancy test.
The Dangers of False Negative Results
When a woman receives a negative result on a pregnancy test, she may assume that she is not pregnant and stop her fertility treatments. During fertility treatments, some women receive progesterone supplements or medication to assist with the fertility process. With a false negative result, there is a chance that women may stop taking the supplement, which can result in possible complications.
It is also possible to get a false positive result. With a false positive, the pregnancy test falsely determines that you may be pregnant. When you get an accurate blood test that determines that you are not pregnant, your hopes may be crushed.
Luckily, you can avoid the dangers of false negative or positive results. Instead of causing unnecessary stress, you should simply wait for your doctor to perform the blood pregnancy test.
Why Are Blood Pregnancy Tests More Accurate?
A blood pregnancy test detects hCG levels in your bloodstream. This is more accurate than checking your urine for hormones for several reasons.
When you take an over-the-counter pregnancy test, drinking too much water or too little water may impact the reading. If you drink too much water, you may dilute your urine. There is no risk of this occurring with a blood test.
There are two types of blood tests – qualitative and quantitative. A qualitative test simply detects the presence of hCG hormones. If the hormones are detectable, you get a positive result, like an over-the-counter pregnancy test.
With a quantitative test, doctors can measure the exact amount of these hormones in your blood. Doctors can even detect minimal levels. Along with providing a more accurate result, doctors may use these readings to track any potential problems with your pregnancy.
The bottom line is that a home pregnancy test should never be used as concrete proof that you are pregnant or not pregnant. While you can use these tests, do not assume that the results are 100% accurate. In fact, in most cases, your best option is to wait for a blood test to be performed by your doctor.