Differences in Ectopic Pregnancy Rates between Fresh and Frozen Embryo Transfer after In Vitro Fertilization: A Large...

Area of Science:

• Reproductive Medicine
• Gynecology
• Obstetrics

Background:

• Ectopic pregnancy (EP) is a growing concern in women undergoing in vitro fertilization and embryo transfer (IVF-ET).
• The
• freeze-all
• policy is increasingly adopted, raising questions about its impact on EP rates.

Purpose of the Study:

• To investigate whether frozen embryo transfer (FET) reduces the incidence of ectopic pregnancy (EP) compared to fresh embryo transfer (ET).
• To compare EP rates between different stimulation protocols in fresh embryo transfer cycles.

Main Methods:

• A large, single-center retrospective study analyzing 16,048 patients with positive human chorionic gonadotrophin (hCG) levels.
• Data collected from January 2013 to March 2022, comparing fresh ET and FET cycles.
• Logistic regression analysis adjusted for confounding factors like age and infertility causes.

Main Results:

• The overall EP rate was 2.09%. FET cycles showed a slightly lower EP rate (2.07%) than fresh ET cycles (2.16%), but this difference was not statistically significant.
• In fresh ET cycles, the long agonist protocol was associated with a significantly lower odds ratio (OR) for EP (0.45) compared to the gonadotropin-releasing hormone antagonist (GnRH-ant) protocol.
• No significant difference in EP rates was observed between FET and fresh ET groups after adjusting for confounding factors.

Conclusions:

• While FET may not significantly alter EP rates compared to fresh ET, the choice of stimulation protocol in fresh ET cycles can influence EP risk.
• The long agonist protocol appears to be associated with a reduced risk of ectopic pregnancy in fresh embryo transfer cycles.