Does cyclic human chorionic gonadotropin secretion indicate embryo loss in in vitro fertilization?

Area of Science:

• Reproductive Endocrinology
• Assisted Reproductive Technologies
• Maternal-Fetal Medicine

Background:

• Singleton in vitro fertilization (IVF) pregnancies exhibit unique human chorionic gonadotropin (hCG) beta subunit curves with cyclic peaks within 56 days post-embryo transfer (ET).
• This cyclic hCG pattern is not observed in spontaneous conceptions.
• Early pregnancy monitoring relies on hCG levels to assess viability and implantation.

Purpose of the Study:

• To compare hCG profiles between singleton IVF pregnancies resulting from single versus multiple embryo transfers (ET).
• To investigate the relationship between hCG level fluctuations and early pregnancy outcomes, including abortion incidence.
• To evaluate the impact of embryo survival on IVF success rates.

Main Methods:

• Statistical comparison of hCG curves from 151 singleton IVF pregnancies.
• Groupings based on the number of embryos transferred (one vs. two, three, or four).
• Analysis of hCG level trends in relation to first-trimester abortion peaks.

Main Results:

• Singleton IVF pregnancies with multiple ETs showed statistically higher hCG levels at specific time points (7-8, 19-20, 37-38 days post-ET) compared to single ETs.
• Declines in hCG levels preceded four out of five observed first-trimester abortion peaks.
• Cyclic hCG secretion may signal early embryo deaths.

Conclusions:

• Multiple embryo transfers result in a higher incidence of multiple implantations than previously estimated.
• Embryo survival in utero is a critical factor influencing the success or failure of IVF.
• Understanding hCG dynamics provides insights into early pregnancy events and IVF outcomes.