IVF Beta hCG Levels in Pregnancy: What Do Your Results Mean?

After in vitro fertilisation (IVF), your first beta hCG blood test result arrives in a single number, and it’s rarely as clear-cut as you hoped. You may find yourself looking at it and wondering whether your beta hCG level is within the expected range and what happens next.

One reading on its own says less than most people expect. Here’s how beta hCG testing works, what the numbers mean, why your clinic usually repeats the test, and what may affect the next result.

What is beta hCG?

Human chorionic gonadotropin (hCG), commonly known as the pregnancy hormone, is a hormone produced during pregnancy that helps support early foetal development. This hormone is produced by the cells that develop into the placenta (the organ that supports the baby during pregnancy) after an embryo attaches to the lining of the uterus. 

hCG is a glycoprotein made up of two subunits, which are alpha and beta. In this context, the “beta” part of the hormone refers to the specific subunit that distinguishes hCG from other similar hormones, such as luteinising hormone (LH) and follicle-stimulating hormone (FSH). Because of this, blood tests that measure beta hCG may detect and measure its level specifically.

Once implantation has occurred, hCG may be detected in both urine and blood. To confirm pregnancy, home pregnancy tests detect hCG in urine and provide a positive or negative result, while a beta hCG blood test measures the amount of the hormone in your bloodstream, providing a more precise result that your doctor could track over time.

What is a beta hCG level?

It refers to the amount of beta hCG hormone detected in your blood at a specific point in time. This is usually measured in milli-international units per millilitre (mIU/mL), indicating the hormone's concentration in a given blood sample. Depending on the results, your doctor may repeat the measurement after a short interval to see how the hormone level changes.

When should beta hCG levels be tested after IVF?

A beta hCG blood test is used to check whether the embryo has attached to the lining of the uterus (implantation), indicating that pregnancy has begun after IVF treatment. The first beta hCG test is started around 9 to 14 days after embryo transfer, but the exact timing depends on the age when the embryos are transferred.

The timing of your test matters because testing too early may not detect enough hCG, leading to a false negative result (a negative test result when you are actually pregnant). If you received hCG injections, early testing may also detect the remaining hormone from the injection, which may cause a false positive result (a positive result even though pregnancy has not occurred).

As the timing of your beta hCG test could affect how the results are interpreted, it is advisable to speak with an O&G doctor to help you understand when to take the test and what the results could mean for your pregnancy. Schedule an appointment with Thomson Medical.

What is the expected level of beta hCG after IVF?

There is no single “perfect” beta hCG level after IVF, as levels may vary between women and pregnancies. Several factors, such as the timing of implantation and when the test is taken, could also affect the beta hCG level.

A single beta hCG reading cannot determine on its own whether an IVF pregnancy is progressing normally, as the hormone level typically increases every 48 to 72 hours in early pregnancy. For this reason, your fertility specialist usually assesses how the level changes over the following days rather than relying on the first result alone.

The following range below represents a general guideline for your initial test result.

• Below 25 mIU/mL: usually classified as borderline, meaning the test has picked up some hCG in your blood, but it is too low to confirm pregnancy and requires a repeat test to see whether the level is increasing as expected.

• 25 mIU/mL or above: generally considered a positive outcome and may suggest implantation has occurred.

• 50 mIU/mL or higher: often seen as a favourable early result when tested around 14 days after embryo transfer.

What factors could affect your beta hCG levels?

Beta hCG levels may vary widely between women and pregnancies because several factors could affect the result, such as: 

• Timing of the test:

  • The timing of your beta hCG test may affect the result because hCG levels usually rise rapidly in early pregnancy. 

  • Testing a few days earlier may give a lower reading, while testing later may show a higher level, as the pregnancy has had more time to produce hCG. 

  • For this reason, your fertility specialist will interpret your result based on the number of days since embryo transfer, which is commonly around 12-14 days after the transfer.

• Stage of the embryos transferred:

  • The embryo stage when transferred may affect the timing of implantation, which may influence your beta hCG levels.

  • For example, a day 3 embryo transfer may result in hCG becoming detectable slightly later, because the embryo needs additional time to develop before implantation.

  • On the other hand, day 5 (blastocyst) embryos are already at a more advanced stage when transferred, so they implant sooner and produce higher hCG.

• Number of embryos transferred:

  • More than one embryo is sometimes transferred to improve the chance of implantation. If more than one embryo implants, hCG levels could be higher on average because more placental tissue is producing the hormone.

  • However, as hCG levels may be similar in singleton and twin pregnancies, a high level alone does not necessarily indicate a multiple pregnancy. Your doctor will use an ultrasound scan to further confirm the number of pregnancies.

• The pregnancy progression:

  • In a progressing pregnancy, hCG levels generally continue to increase during the early stages. 

  • If the level rises slowly, stops increasing, or falls, it may indicate that the pregnancy is not developing normally, such as in a chemical pregnancy, an early miscarriage, or an ectopic pregnancy.

• Laboratory sensitivity and method:

  • Different laboratories may use different methods to measure hCG, which could lead to slight differences in your results. 

  • Your doctor may recommend using the same laboratory and testing method for repeat tests, making it easier to compare your results and track how your beta hCG level changes over time.

Since several factors may affect your beta hCG levels, speaking with yourO&G doctormay help you understand what may influence your results and how they should be interpreted.Schedule an appointmentwith Thomson Medical.

What your doctor may recommend based on your result?

Once your doctor has reviewed your beta hCG results, they will guide you on the next steps, which are based on your individual test results.

• Positive result:

  • If your result is positive, your doctor will advise you on whether to continue taking any prescribed IVF medications, such as progesterone. 

  • Your fertility specialist may also recommend further blood tests or a transvaginal ultrasound to monitor your early pregnancy outcome, embryo sacs, and their location in the uterus.

  • As your pregnancy progresses, attending regular antenatal care (routine pregnancy check-ups) may help your doctor monitor your health and your baby's development.

• Low or borderline result:

  • A low or borderline result may require further monitoring, especially if you had the test early. 

  • Your doctor may recommend repeating the beta hCG blood test after a short interval (around 48 to 72 hours) to check whether your hCG level is rising. 

• Negative result:

  • If your test result remains negative, it means that the test did not detect enough hCG to indicate pregnancy. 

  • Follow your fertility specialist's advice regarding your IVF medications, and avoid stopping any medication on your own. 

  • Your fertility specialist may also arrange a follow-up consultation to discuss the outcome of the cycle, answer any questions you may have and talk about possible next steps.

FAQ

Can you be pregnant with low hCG after IVF?

Can PMOS affect beta hCG levels after IVF?

Can beta hCG predict the baby’s gender?

Can hCG levels increase if I am not pregnant?

The information provided is intended for general guidance only and should not be considered medical advice. For personalised advice based on your conditions,schedule an appointmentwith Thomson Medical.