hCG Levels vs. Ultrasound: What to Expect in Early Pregnancy

Question
I'm just wondering if hCG levels correspond with U/S results. For example, if I'm only 5w1d pregnant, but my beta hCG level is 7800 would I be more likely to see a fetal pole? If I didn't see a fetal pole with an hCG of 7800 is that bad, even though I'm only 5w1d?

Answer
Dear Abby,

There can be a somewhat indirect correlation between ultrasound findings and hCG levels. There is an expectation of what we would expect to see on an ultrasound at different points in a pregnancy, just as there is an expectation of a certain level of hCG at certain levels in a pregnancy.

For example, with abdominal ultrasonography, the hCG level at which we expect to see an intrauterine gestational sac in a woman with a normal uterine pregnancy is 6500 mIU/ml. With vaginal ultrasonography, which increases the resolution because of the closer proximity to the involved tissue, the level drops to 2800 mIU/ml.

"Williams Obstetrics" cites somewhat of a guideline for this. It says we would expect to see a fetal pole at: 40.3 days from LMP +/- 3.4 days and/or a beta hCG level of 3783 mIU/ml +/- 683.

The normal range for hCG at 5 weeks is 18 - 7,340 mIU/ml, so you are already a bit higher than normal. This may be good but a high hCG MAY also be an indicator of a molar pregnancy.

Your doctor will follow up on the ultrasound, I'm sure. I would anticipate that he would order another one within the next 2 weeks in order to try and visualize the fetal pole. Until then, there really is nothing you can do about this at all. Wait and see what the ultrasound shows and what your doctor evaluates this to be.

I hope this information has helped you and answered your question. I wish you well and will have a good thought for you.

Brenda