It is NOT abnormal for the rise in hCG to slow down after several weeks into pregnancy!
Good luck!
TIMING AND INTERPRETATION OF hCG BLOOD PREGNANCY TESTS
Geoffrey Sher MD
Going through IVF is a major investment, emotionally, physically, and financially, for every patient or couple. One of the most crucial moments is receiving the result of the blood test for human chorionic gonadotropin (hCG) pregnancy. It’s a big deal! The days after the embryo transfer, waiting for this result, can be extremely stressful. That’s why it’s crucial for the IVF doctor and staff to handle this information with care and professionalism. They should be accessible to the patient/couple and provide results promptly and sensitively.
Testing urine or blood to check for human chorionic gonadotropin (hCG) is the best way to confirm pregnancy. Urine tests are cheaper and more commonly used. They are also more convenient because they can be done anywhere. However, blood tests are more reliable and sensitive than urine tests. They can detect pregnancy earlier and at lower hCG levels. Blood tests are also more accurate and can track changes in hCG levels over time. Urine tests can detect hCG when blood levels are above 20IU, which is about 16-18 days after ovulation or 2-3 days after a missed period. Blood tests can measure any concentration of hCG about 12-13 days after ovulation.
Detecting hCG in the blood early on and tracking its increase is especially useful for women undergoing fertility treatments like controlled ovarian stimulation or in vitro fertilization. The sooner hCG is detected and measured, the more information can be gathered about the success of implantation and the health of the developing embryo.
Typically, two beta hCG blood tests are done, spaced 2-4 days apart. It’s best to wait for the results of the second test before reporting on the pregnancy. This is because an initial result can change, even from equivocal or negative to positive. Sometimes a normal embryo takes longer to implant, and the hCG level can be initially low or undetectable. Regardless of the initial level, the test should be repeated after two days to check for a significant rise in hCG. A significant rise usually indicates that an embryo is implanting, which suggests a possible pregnancy. Waiting for the second test result helps avoid conveying false hope or disappointment.
It’s important to note that beta hCG levels don’t double every two days throughout pregnancy. Once the levels rise above 4,000U, they tend to increase more slowly. Except in specific cases like IVF using an egg donor or transfer of genetically tested embryos, the birth rate following IVF in younger women is around 40% per embryo transfer. Patients need to have realistic expectations and should be informed about how and when they will receive the news, as well as counseling in case of a negative outcome.
When an embryo starts to implant, it releases the pregnancy hormone hCG into the woman’s bloodstream. Around 12 days after egg retrieval, 9 days after a day 3 embryo transfer, or 7 days after a blastocyst transfer, a woman should have a quantitative beta hCG blood pregnancy test performed. By that time, most of the hCG injected to prepare the eggs for retrieval should have cleared from the bloodstream. So, if the test detects more than 10 IU of hCG per ml of blood, it indicates that the embryo has attempted to implant. In third-party IVF (e.g., ovum donation, gestational surrogacy, embryo adoption, or frozen embryo transfers), no hCG trigger is administered, so any amount of hCG detected in the blood is considered significant.
Sometimes, there is a slow initial rise in hCG between the first and second tests (failure to double every 48 hours). In such cases, a third and sometimes a fourth hCG test should be done at two-day intervals. A failure to double on the third and/or fourth test is a poor sign and could indicate a failed or dysfunctional implantation. In some cases, a progressively slow rising hCG level might indicate an ectopic pregnancy, which requires additional testing and follow-up.
In certain situations, the first beta hCG level starts high, drops with the second test, and then starts doubling again. This could suggest that initially, multiple embryos started to implant but only one survived to continue a healthy implantation.
It’s customary for the IVF clinic staff to inform the patient/couple and the referring physician about the hCG pregnancy test results. Often, the IVF physician or nurse-coordinator coordinates with the referring physician to arrange all necessary pregnancy tests. If the patient/couple prefer to make their own arrangements, the program should provide detailed instructions.
In some cases, when the two blood pregnancy tests show that one or more embryos are implanting, certain programs recommend daily injections of progesterone or the use of vaginal hormone suppositories for several weeks to support the implantation process. Others give hCG injections three times a week until the pregnancy can be confirmed by ultrasound examination. Some IVF programs don’t prescribe any hormones after the embryo transfer.
Patients with appropriate doubling of hCG levels within two days after frozen embryo transfer (FET) or third-party IVF procedures such as surrogacy or egg donation may receive estradiol and progesterone injections, often along with vaginal hormone suppositories, for 10 weeks after the implantation is diagnosed by blood pregnancy testing.
A positive Beta hCG blood pregnancy test indicates the possibility of conception, but ultrasound confirmation is needed to confirm the pregnancy. Until then, it is referred to as a “chemical pregnancy.” Only when ultrasound examination confirms the presence of a gestational sac, clinical examination establishes a viable pregnancy, or after abortion when products of conception are detected, is it called a clinical intrauterine pregnancy.
A significantly elevated hCG blood level without concomitant detection of an gestational sac inside the uterus by ultrasound after 5 weeks gestation raises the suspicion of an ectopic (tubal) pregnancy.
The risk of miscarriage gradually decreases once a viable clinical pregnancy is diagnosed (a conceptus with a regular heartbeat of 110-180 beats per minute). From this point onward, the risk of miscarriage is usually 10- 15% for women under 40 years old and around 35% for women in their early forties.
Dealing with successful IVF cases is relatively easy as everyone feels happy and validated. The real challenge lies in handling unsuccessful cases. Setting rational expectations from the beginning is crucial. In some cases (fortunately rare), emotional pressure may overwhelm the patient/couple, leading to a need for counseling or psychiatric therapy. I always advise my patients that receiving optimal care doesn’t always guarantee the desired outcome. There are many variables beyond our control, especially the unpredictable nature of fate. With around 36 years of experience in this field, I strongly believe that when it comes to IVF, the saying “man proposes while God disposes” always holds.
There are a few important things to consider when interpreting blood hCG levels. Levels can vary widely, ranging from 5mIU/ml to over 400mIU/ml, 10 days after ovulation or egg retrieval. The levels double every 48-72 hours until the 6th week of pregnancy, after which the doubling rate slows down to about 96 hours. By the end of the 1st trimester, hCG levels reach 13,000-290,000 IU and then slowly decline to around 26,000-300,000 IU at full term. Here are the average hCG levels during the first trimester:
- 3 weeks after the last menstrual period (LMP): 5-50 IU
- 4 weeks LMP: 5-426 IU
- 5 weeks LMP: 18-7,340 IU
- 6 weeks LMP: 1,080-56,500 IU
- 7-8 weeks LMP: 7,650-229,000 IU
- 9-12 weeks LMP: 25,700-288,000 IU
Most doctors wait until around the 7th week to perform an ultrasound to confirm pregnancy. By that time, the heartbeat should be clearly visible, providing a more reliable assessment of the pregnancy’s viability.
In some cases, blood hCG levels can be unusually high or increase faster than normal. This could indicate multiple pregnancies or a molar pregnancy. Rarely, conditions unrelated to pregnancy, such as certain ovarian tumors or cancers, can cause detectable hCG levels in both blood and urine.
To summarize, testing urine or blood for hCG is the most reliable way to confirm pregnancy. Urine tests are more common and convenient, while blood tests are more accurate and can detect pregnancy earlier. Tracking hCG levels in the blood is especially important for women undergoing fertility treatments. It’s essential to wait for the results of a second blood test before confirming pregnancy to avoid false hope or disappointment. Interpreting hCG levels requires considering various factors, and doctors usually perform an ultrasound around the 7th week for a more accurate assessment. Unusually high hCG levels may indicate multiple pregnancies or other conditions unrelated to pregnancy. Providing sensitive and timely communication of results is crucial for IVF clinics to support patients through the emotional journey.
_______________________________________________________________________
ADDITIONAL INFORMATION:
I am attaching online links to two E-books which I recently co-authored with my partner at SFS-NY (Drew Tortoriello MD)……. for your reading pleasure:
1.From In Vitro Fertilization to Family: A Journey with Sher Fertility Solutions (SFS) “
https://sherfertilitysolutions.com/sher-fertility-solutions-ebook.pdf
- “Recurrent Pregnancy Loss and Unexplained IVF Failure: The Immunologic Link
https://drive.google.com/file/d/1iYKz-EkAjMqwMa1ZcufIloRdxnAfDH8L/view
- If you are interested in having an online consultation with me, please contact my assistant, Patti Converse at 702-533-2691 or go to concierge@sherivf.com .
- Also, I have just started a new Podcast https://rumble.com/c/c-3304480. Feel free to take a look-see……… And please spread the word!
