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Apr 21, 2023
4 min read

Why do experts suggest testing 14 days after the embryo transfer?

The two-week period during which you have to wait to take a pregnancy test and find out if your fertility treatment has been successful can be very difficult. So why exactly do we have to wait 14 days? 

After the embryo transfer, most fertility clinics will give you a pregnancy test with instructions on how to use it on day 14 after the embryo transfer. But why do we have to wait so long after going through so many procedures and dreaming about having a baby? Is it worth testing earlier or should we listen to the professionals? If we decide to go ahead and take the test early, which kind should we use? 

How do we detect a pregnancy?

There are three ways to find out if we have conceived or not: home pregnancy test, blood test and an examination by a gynaecologist. The most definite way is, of course, to have an ultrasound test, however, most practitioners wait to perform the first pregnancy ultrasound until the 6th week of pregnancy (4 weeks after the embryo transfer). The home pregnancy tests work by detecting hCG levels in urine. They are very affordable and show the results within minutes. Nevertheless, if you test too early, it is possible that your hCG levels are too low for the pregnancy test to detect them. The third option is to have a blood test, which is also called a beta test. It detects whether the hCG hormone is present in your blood or not, but on top of that it can also measure its amount in the blood. Beta tests are more costly and you have to wait a few days for the result, but they can recognise a much smaller amount of HCG than the urine tests, which means that they can detect a pregnancy a few days earlier than the at-home tests.    

What is the main difference between various pregnancy tests? 

The most important difference between tests is their sensitivity to hCG. There are many kinds of at-home pregnancy tests on the market with sensitivity of 20 mlU/ml to 50mlU/ml for the high-sensitivity test. The more sensitive the test, the smaller amount of hCG hormone can be detected. It would be logical to think that a more sensitive test can confirm a pregnancy much sooner than the less sensitive ones, but in reality, they can detect a pregnancy only 1 to 2 days earlier than the less sensitive tests. 

When can urine tests detect a pregnancy? 

After an oocyte retrieval and the fertilisation process, implantation occurs approximately 6 days later. 10 to 11 days after fertilisation the production of the hCG hormone begins. Compared to blood tests, urine hCG level detection is 2 to 3 days behind so, technically, you can get a positive test 4 to 6 days before your next period. However, it is worth noting that if you get the long-awaited “big fat positive” result, it still does not mean that you are 100% pregnant. This only indicates that there may be some changes going on in your body but it is too soon to tell. This also works the other way around. If you get a negative result on your home pregnancy test, you may actually be pregnant, but the test is not able to detect such low hCG levels. 

Why is it ‘dangerous’ to test too soon?

It is possible for the embryo to implant and the body to start producing hCG. However, in some cases the implantation process can stop and the pregnancy fails. Let’s say that you decide to take a home pregnancy test earlier than recommended and you get a positive result. If the early pregnancy fails and you get your period a few days after your positive result, you may be extremely disappointed. 

The trigger shot used during the fertility process contains hCG. If you decide to take a pregnancy test too soon after the shot, you may get a false positive result because the pregnancy test will be able to detect the hCG levels from the shot. It takes about 10 days for the hCG to clear out of the blood and urine. 

In my opinion, it is worth it to wait a few days longer and take the pregnancy test the full 14 days after fertilisation and avoid unnecessary disappointments. Getting a false positive result or a little glimpse of uncertain hope is too scary for me. 

Here is a quote from Joyce Meyer for all you ladies going through the dreaded 2 week wait: “Patience is not the ability to wait, but the ability to keep a good attitude while waiting.” 

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