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Ectopic pregnancy after in vitro fertilization: differences between fresh and frozen-thawed cycles

TitleEctopic pregnancy after in vitro fertilization: differences between fresh and frozen-thawed cycles
Publication TypeJournal Article
Year of Publication2015
AuthorsLondra, L, Moreau, C, Strobino, D, Garcia, J, Zacur, H, Zhao, Y
JournalFertil Steril
Date PublishedJul
ISBN Number1556-5653 (Electronic)0015-0282 (Linking)
Accession Number25956363
Keywords*Tissue Donors, Adult, Cohort Studies, Cryopreservation/*methods/*trends, Ectopic pregnancy, embryo transfer, Embryo Transfer/adverse effects/methods/trends, Female, Fertilization in Vitro/adverse effects/*methods/*trends, Humans, in vitro fertilization, Pregnancy, Pregnancy, Ectopic/diagnosis/*epidemiology, Retrospective Studies, Risk Factors

OBJECTIVE: To evaluate whether the uterine environment is associated with the risk of ectopic implantation by comparing outcomes of fresh and frozen-thawed embryo transfers. DESIGN: Retrospective historical cohort. SETTING: Not applicable. PATIENT(S): We used the Society for Assisted Reproductive Technologies (SART) database to identify pregnancies that resulted from fresh and frozen blastocyst transfers from 2008 to 2011. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): We determined the proportion of ectopic (EP) versus intrauterine-only pregnancies resulting from fresh or frozen embryo transfers in autologous and donor-oocyte cycles. Generalized estimation equation regression models were used to adjust for maternal and treatment characteristics. RESULT(S): Among 103,070 cycles that resulted in a clinical pregnancy, 1.38% were ectopic. The odds of EP were 65% lower in women who had a frozen compared with a fresh transfer in autologous cycles. Donor-oocyte transfers had lower odds of EP compared with autologous cycles, with no difference between fresh and frozen donor transfers. Women who had both a fresh and a frozen transfer with autologous oocytes had a higher risk of EP in their fresh cycles compared with their frozen cycles. CONCLUSION(S): Embryo transfers in cycles without ovarian hyperstimulation, such as frozen or donor cycles, were associated with lower rates of EP compared with fresh autologous cycles, suggesting that a difference in the tubal-uterine environment contributes to abnormal implantation after IVF.