When to take pregnancy test after embryo transfer from IVF treatment
When can you take a pregnancy test after IVF is one of the most common question asked by people who are going through IVF treatment. After embryo transfer, the clinic will generally recommend you to wait 9-11 days before taking a pregnancy test.
The earliest you can test that will give you a reasonably reliable result is 14 days after the day of egg collection (if it is a fresh cycle). So it is 9 days post 5-day embryo transfer OR 11 days days post 3-day embryo transfer. And you should do blood pregnancy test rather than urine pregnancy test.
Here is the reasons why….
Blood test is the most reliable pregnancy test
Blood test for beta subunit of HCG (human chorionic gonadotropin) hormone level in the blood stream is considered the most reliable and accurate way to determine whether you are pregnant. HCG is released into blood stream by placenta tissues which are normally formed after the embryo implanted itself into the uterine wall. The implantation process generally takes place between 6-12 days after fertilisation.
HCG is released into blood stream soon after placenta tissues have formed and the hormone level increases daily during the first trimester as long as the pregnancy continues to develop.
Note that the level of HCG are different from person to person, so some pregnant women could have a lot lower HCG level compared to others at the same gestational age. So it is better to wait to a minimum of 14 days after egg collection before performing a blood pregnancy test.
In some cases, early test might yield true positive result, for example, in twins pregnancy which produces much higher HCG level to single pregnancy
Doubling rule
Regardless of the first blood test HCG level, the hormone level should double every 48 to 72 hours for a pregnancy to be considered normal. Sometimes a rise of 50-60% is also considered normal depending on how early the pregnancy is.
Most clinics performs at least two blood pregnancy tests 48-72 hours apart in order to confirm a well-developed pregnancy.
HCG levels that does not follow this rule may indicate that the pregnancy is failing.
Why you should not test early ?
False positive if tested too early
False positive is likely the case if a pregnancy test is done within 7 days after egg collection. The positive pregnancy test detected in this timeframe is triggered by the remnant of HCG shot used to trigger the final egg maturation stage, which is normally need to be given the night before the egg collection day.
False negative if not wait long enough
If you tested before 14 days after egg collection day, you might get a false negative result from a urine pregnancy test and unnecessary letting yourself down. This is because it takes some times for an implanted embryo to release high enough HCG level in your blood stream to pass into urine to the level that can be detectable by home pregnancy test.
In some cases such as twin pregnancy true positive test can be expected in early days.