From the Guidelines
For a 31-year-old female with a beta-hCG level of 5.3 at 14 days after intrauterine insemination (IUI), I recommend repeating the beta-hCG test in 48-72 hours. This current level is very low and considered indeterminate - it's above some labs' threshold for a negative result (usually <5) but too low to confirm a viable pregnancy, as a patient is considered pregnant when the serum hCG value is greater than 5 mIU/mL 1. When repeating the test, you should look for the beta-hCG value to approximately double every 48-72 hours in a healthy early pregnancy. Unfortunately, with a level this low at 14 days post-IUI, the possibility of a viable ongoing pregnancy is relatively low. This could represent either a very early pregnancy that was just beginning to implant, a chemical pregnancy (very early miscarriage), or a false positive result.
Some key points to consider in this scenario include:
- The discriminatory level of hCG, which refers to the level at which a gestational sac should always be seen on transvaginal US in a normal singleton IUP, has historically been suggested as 1,000 to 2,000 mIU/mL 1.
- However, even a level of 2,000 mIU/mL has been found to be too low to exclude a normal IUP, and if there is no transvaginal US evidence of a gestational sac when a single serum hCG is 3,000 mIU/mL or higher, it is unlikely there will be a viable IUP 1.
- For a hemodynamically stable patient with no sonographic evidence of an IUP or ectopic pregnancy, management decisions should generally not be made based on a single hCG level, and follow-up hCG assay and US are usually appropriate in such a scenario 1.
While waiting for the repeat test, it is recommended to:
- Continue any prescribed progesterone supplementation if you're taking it
- Avoid alcohol and tobacco
- Take prenatal vitamins The low hCG level at this point after IUI is concerning because implantation typically occurs 6-10 days after fertilization, with hCG levels usually reaching higher values by 14 days post-procedure in viable pregnancies. Your fertility specialist should guide further management based on the trend in your repeat beta-hCG results.
From the Research
Follow-up for a 31-year-old female with a beta human chorionic gonadotropin (bhCG) level of 5.3
- A bhCG level of 5.3,14 days after an intrauterine insemination (IUI) cycle, is relatively low 2
- Low initial serum beta hCG is a good predictor of early pregnancy failure 2
- The patient's bhCG level is below the threshold of 10 mIU/mL, which is often used to define a positive pregnancy test 2
Possibilities of Pregnancy
- The low bhCG level may indicate a non-viable pregnancy or an ectopic pregnancy 3, 4
- However, it is also possible that the pregnancy is still viable, but the bhCG level is not yet elevated enough to confirm this 2
- Further testing, such as ultrasound and repeat bhCG measurements, would be necessary to determine the viability of the pregnancy 5, 6
Next Steps
- Repeat bhCG measurement in 48-72 hours to assess for an appropriate increase in bhCG levels 2, 5
- Transvaginal ultrasound to evaluate for the presence of an intrauterine pregnancy or an ectopic pregnancy 3, 4
- Consider consulting with a fertility specialist or obstetrician to discuss the patient's options and determine the best course of action 6