Beta hCG levels; what do they show?
The analysis of the beta-hCG hormone establishes whether or not there is a pregnancy. When the initial level is positive, the most important thing is to wait how it evolves until the first ultrasound.
For the vast majority of women (and men), the beta-hCG hormone is a complete unknown until they start an assisted reproduction treatment and it then becomes a fundamental concept. Why is it so important? “Beta is a hormone produced by the pregnancy itself, and is the first sign of pregnancy we have,” explains Dr. Clara Colome, of the Eugin Clinic.
Fourteen days after an embryo transfer or an artificial insemination, a simple blood sample is taken to establish the exact levels of this hormone in the blood. Secretion of beta is the first sign the embryo sends us about its implantation.
The result of the beta test is positive when it is higher than 5 International Units (IU), although this cut-off point may vary slightly depending on each laboratory’s reference values. In this case we will know that a pregnancy has been achieved, although we won’t have information about whether it is a singleton or twin pregnancy.
How beta levels evolve is key
Normally, when the beta level is positive, after 48 or 72 hours, the blood test is repeated, just to see how it is evolving. As pointed out by a specialist at Eugin, “what normally happens in pregnancy is that the beta levels have doubled after those two days have passed.”
If the beta levels don’t double in that period, in fact, they may decrease, which could be a sign that that the pregnancy is not developing properly, or if they remain stable or increase without managing to double the initial level, this latter case could mean that we would be dealing with an ectopic pregnancy, that is, one which develops outside the uterus.
Confirmation: an ultrasound
Even if the results are normal, confirming the correct course of the pregnancy is not possible until the first ultrasound, when the beta level has already surpassed 1,000 units. This ultrasound is done two or three weeks after the first hormone test, or, which is the same, after six or seven weeks from the date of the woman’s last menstrual period, when we can already view the gestational sac and the embryo with a positive heartbeat.
“The beta levels provide indications about different aspects, but you always have to wait for the confirmation given by the ultrasound, says Dr. Colome. It is then, from the moment the pregnancy has been confirmed, when a new stage unfolds on the journey towards motherhood.