The dreaded two week wait is the period spanning between artificial insemination or the embryo transfer (after an IVF treatment) and the pregnancy test that will measure the levels of the hormone hCG.
We wanted to find out more and so turned to a leading clinic, IVF Spain, to talk us through the process.
The hCG (human chorionic gonadotropin) is a glycoprotein produced by the embryo’s trophoblastic cells as it implants in the mother’s womb. Therefore, measuring the Beta-hCG levels turns out to be a very reliable indicator when evaluating whether the longed for pregnancy has indeed taken place.
To confirm the viability of the process, this hormone’s levels must maintain an exponential increase until the end of the first trimester. At 12 weeks, this is a time in which the hCG values will decrease and keep stable until the end of the pregnancy.
10 days after the insemination or the embryo transfer is when the blood’s levels of Beta-hCG are measured.
This is usually a difficult period for the patients, who may feel very anxious, since it is inevitable to try to find an immediate answer as to whether the fertility treatment has been successful or not.
The Beta-hCG can also be detected in the urine, although for a more accurate and reliable result it is recommended that your fertility centre, or a nearby laboratory performs the blood analysis.
The urine tests are limited to more inferior levels of mUI/ml (international miliunits per millilitre) than those in the blood and, if the test is not carried out at the right time, we can obtain a false negative, that is, a negative result even when the embryo has actually implanted.
False positives are less common, but they can also happen.
This is possible, for example, in a case of an ectopic pregnancy, which is an embryo implantation outside of the uterus. In this situation the beta will not increase exponentially, although it can only be confirmed through an ultrasound.
We can also obtain a false positive when an anembryonic pregnancy occurs. In this case the beta will be positive because the embryo has implanted, but the gestational sac is empty.
A biochemical pregnancy may also cause false positives. A “biochemical” occurs when implantation has taken place but the embryo has stopped developing.
On rare occasions, an ovarian cyst may also produce a false positive result.
If when performing the test, we find low levels of the hormone: 5-25 mUI/ml, the test must be repeated after 48 hours in order to evaluate the increase pattern of the hormone.
An elevated positive beta in cases of a double embryo transfer can be due a double implantation, but to actually confirm this, an ultrasound must be performed.
Only the patients that have gone through this seemingly endless two week wait will know how hard it is and the emotional roller coaster it subjects them to.
This is why, certainly in our fertility clinic at IVF Spain, patient attention is key and we always ensure patients receive a personalised and attentive communication. This is so important to take away the distress that patients may suffer during this long waiting period.