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Measuring and interpreting Blood hCG to Assess Pregnancy Viability Following ART Treatments

by Dr. Geoffrey Sher on December 23, 2015

I know of no medical announcement associated with the degree of emotional anticipation and anguish as that associated with a pending diagnosis/confirmation of pregnancy following infertility treatment. In fact, hardly a day goes by where I am not confronted by a patient anxiously seeking interpretation of a pregnancy test result.

Testing urine or blood for the presence of human chorionic gonadotropin (hCG) is the most effective and reliable way to confirm conception. The former, is far less expensive than the latter and is the most common method used. It is also more convenient because it can be performed in the convenience of the home setting. However, urine hCG testing for pregnancy is not nearly as reliable or as sensitive e as is blood hCG testing. Blood testing can detect implantation several days earlier than can a urine test. Modern pregnancy urine test kits can detect hCG about 16-18 days following ovulation (or 2-3 days after having missed a menstrual period), while blood tests can detect hCG, 12-13 days post-ovulation (i.e. even prior to menstruation).

The ability to detect hCG in the blood as early as possible and thereupon to track its increase, is particularly valuable in women undergoing controlled ovarian stimulation (COS) with or without intrauterine insemination (IUI) or after IVF. The earlier hCG can be detected in the blood and its concentration measured, the sooner levels can be tracked serially over time and so provide valuable information about the effectiveness of implantation, and the potential viability of the developing conceptus.

There are a few important points that should be considered when it comes to measuring interpreting blood hCG levels. These include the following:

  • All modern day blood (and urine) hCG tests are highly specific in that they measure exclusively for hCG. There is in fact no cross-reactivity with other hormones such as estrogen, progesterone or LH.
  • Post conception hCG levels, measured 10 days post ovulation or egg retrieval can vary widely (ranging from 5mIU/ml to above 400mIU/ml. The level will double every 48–72 hours up to the 6th week of gestation whereupon the doubling rate starts to slow down to about 96 hours. An hCG level of 13,000-290, 0000 mIU/ml is reached by the end of the 1st trimester (12 weeks) whereupon it slowly declines to approximately 26,000– 300,000 mIU/ml by full term. Below are the average hCG levels during the first trimester:
    • 3 weeks LMP: 5 – 50 mIU/ml
    • 4 weeks LMP: 5 – 426 mIU/ml
    • 5 weeks LMP: 18 – 7,340 mIU/ml
    • 6 weeks LMP: 1,080 – 56,500 mIU/ml
    • 7 – 8 weeks LMP: 7, 650 – 229,000 mIU/ml
    • 9 – 12 weeks LMP: 25,700 – 288,000 mIU/ml
  • A single hCG blood level is not sufficient to assess the viability of an implanting embryo. Caution should be used in making too much of an initial hCG level. This is because a normal pregnancy can start with relatively low hCG blood levels. It is the rate of the rise of the blood hCG level that is relevant.
  • In some cases the initially hCG level is within the normal range, but then fails to double in the ensuing 48-72hours. In some cases it might even plateau or decline, only to start doubling appropriately thereafter. When this happens, it could be due to:
    • A recovering implantation, destined to develop into a clinical gestation
    • A failing implantation (a chemical pregnancy)
    • A multiple pregnancy which is spontaneously reducing (i.e., one or more of the concepti is being lost) or,
    • An ectopic pregnancy which will either absorb spontaneously (a chemical-tubal gestation), or evolve into a full blown tubal pregnancy continue and declare itself through characteristic symptoms and signs of an intraperitoneal bleed.
  • The blood hCG test needs to be repeated at least once after 48h and in some cases it  will need to be repeated one or more times (at 48h intervals) thereafter, to confirm that implantation is progressing normally.
  • Ultimately the diagnosis of a viable pregnancy requires confirmation of the presence of an intrauterine gestational sac by ultrasound examination. The earliest that this can be achieved is when the beta hCG level exceeds 1,000mIU/ml (i.e., around 5-6 weeks).
  • Most physicians prefer to defer the performance of a routine US diagnosis of pregnancy until closer to the 7th week. This is because by that time, cardiac activity should be clearly detectable, allowing for more reliable assessment of pregnancy viability.
  • There are cases where the blood beta hCG level is extraordinarily high or the rate of rise is well above the normal doubling rate. The commonest explanation is that more than one pregnancy has implanted. However in some cases it can point to a molar pregnancy  
  • Finally, there on rare occasions, conditions unrelated to pregnancy can result in detectable hCG levels in blood and urine. They include ovarian tumors that produce hCG, such as certain types of cystic teratomas (dermoid cysts) and some ovarian cancers such as dysgerminomas.
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  • Angela Oscarson - July 14, 2018 reply

    Good Morning Dr. Sher,

    My husband and I had our 5 day 1 embryo transfer on 5 July, we did our first blood test on 13 July, 8dp5dt and our HCG level was 83. The nurse advised that this was a good sign that for the first test anything over 50 is a good level. We have our next HCG test on Monday the 16th, currently on progesterone suppository, No bleeding, nausea, occasional bloating and cramps and breast tenderness, but does this first HCG level seem okay or too low?

    Thank you.

    V/R,

    Angela

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - July 14, 2018 reply

    Seems encouraging!

    Good luck~

    Geoff Sher

  • Maggie - July 1, 2018 reply

    I am 10dp5dt. One embryo. On days 7,8,9 HPT were all positives. Today, I took two (same brand as before and first urination of the day like before). Both came back negative. My blood test was this afternoon and my doctor called and said my HCG is low. He wants me to continue the meds for two days and redraw. I’m feeling very scared and anxious. I haven’t seen any positive literature on decreasing hcg. He didn’t give me the exact lab number but said it was pretty low. Thoughts? Thank you

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - July 2, 2018 reply

    I share your concern but I would wait to see if the hCG doubles in the next two days!

    Geoff Sher

  • Lori - June 29, 2018 reply

    Hello doctor. I had 2 embryo 5dt. First HCG was 8dp5dt at 26. Went back 2 days later 10dp5t doubles to 67. Could this be a late implantation? I am a little worried. Tomorrow I will be testing again and that will be 14dp5dt. I have an US scheduled for end of next week. On day 9 past transfer I had a little bleeding and some spotting which didn’t last for more than an hour. Please give me your thoughts. Thank you so much!

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 29, 2018 reply

    I am not overly concerned about your slight painless bleed. Time will be the determinant.

    Good luck!

    Geoff sher

    Lori - June 29, 2018 reply

    Thank you so much Dr. Sher! I really appreciate it!!

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 29, 2018 reply

    You are very welcome Lori!

    Geoff Sher

  • Alana - June 28, 2018 reply

    I had a very late starting hcg, but it has doubled more or less normally (I think!). It was 22 at 14dp5dt, then 136 at 18dp5dt, then 291 at 20dp5ft, 500 at 22dp5dt, and 1296 at 26dp5dt. I have been asked to come in for a scan in two weeks’ time, no more blood tests. I assume it will not end well, because of the low numbers (and why did it take so long to get started?). But others are saying it’s the doubling that counts and that this is fine. What do you think?

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 28, 2018 reply

    It could still be OK. Have an US done in 1 week from now.

    Geoff Sher

    Alana - June 28, 2018 reply

    Thank you for your reply, Dr Sher.

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 28, 2018 reply

    You are very welcome Alana!

    Geoff Sher

  • Swetha - June 25, 2018 reply

    Hi Dr Sher,

    My hcg level 10 days post IUI is 53. I’m waiting to get the next draw tomorrow at 12dpo. I just wanted to check if 53 is a good number for 10 days after IUI

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 25, 2018 reply

    Very good number…congratulations and good luck!

    Geoff Sher

    Swetha - June 26, 2018 reply

    Hi Dr Sher,
    I got my results back from second blood draw at 13dpo and it is 140. Doubling time is 51.5 hours. I’m a little worried because the doubling time is usually less than 48 hours this early in pregnancy.
    Thank you so much

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 27, 2018 reply

    It could still be OK!

    Good luck!

    Geoff Sher

    swetha - June 28, 2018

    Hi Dr Sher,

    Thank for your quick response. I really appreciate it.
    I got my results from 15dpo and HCG is only 236. It increased from 140 to 236 in 48 hours. Now the doubling time is 63.5 hours. I’ve heard that 48-72 hours is ok but the doubling time is just increasing. I have another blood draw at 17dpo. I had a blighted ovum and a chemical pregnancy recently. Is there any hope at this point?

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - June 28, 2018

    I would wait a week + andf do an ultrasound for an indication of viability!

    Good luck!

    Geoff Sher

    swetha - July 1, 2018

    Hi Dr Sher,
    Thank you for your response. My doctor is not giving the ultrasound until atleast 2 weeks more. Following are my HCL levels. I’m listing them again for your reference
    10 DPO 53
    13DPO 140 (Doubling time 51 hours)
    15DPO 236 (Doubling time 64 hours)
    17DPO 592 (Doubling time 36 hours)
    I will be going for another hcg tomorrow at 20DPO.
    I would really appreciate if you can share your opinion based on my HCG levels.

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - July 2, 2018

    Sorry Swetha,

    Only time will tell!

    Geoff Sher

    Swetha - July 11, 2018

    Hi Dr Sher,
    I wanted to share an update. My hcg levels increased every 36 hours later on. We had an ultrasound today at 6 weeks 1 day. Doctor could see two sacs with fetal poles and heartbeats. Baby A had heart rate of 110 and baby B had heart rate of 105. Are these normal rates for 6 weeks 1 day ?

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - July 11, 2018

    It is a little on the slow side but give it 1 more week and see. It could all turn out fine still!

    Good luck!

    Geoff Sher

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