F S Rep. 2021 Jul 3;2(4):421-427. doi: 10.1016/j.xfre.2021.06.010. eCollection 2021 Dec.
ABSTRACT
OBJECTIVE: To investigate whether there is a difference in the ectopic/heterotopic pregnancy rate of blastocyst-stage frozen-thawed embryo transfers (FETs) compared with that of cleavage-stage FETs.
DESIGN: A retrospective cohort study.
SETTING: Not applicable.
PATIENTS: Women undergoing autologous FETs at either the blastocyst stage (n = 118,572) or the cleavage stage (n = 117,619), as reported to the Society for Assisted Reproductive Technology from 2004 to 2013.
INTERVENTIONS: None.
MAIN OUTCOME MEASURES: Pregnancy outcomes, specifically ectopic pregnancy rates and heterotopic pregnancy rates.
RESULTS: Among those who became pregnant, there was a significantly lower incidence of ectopic/heterotopic pregnancies in blastocyst-stage FETs versus that in cleavage-stage FETs (0.8% vs. 1.1%). The differences in ectopic/heterotopic pregnancy rates remained statistically significant after controlling for confounders such as tubal factor infertility and number of embryos transferred.
CONCLUSIONS: Blastocyst-stage FET was associated with a lower ectopic/heterotopic pregnancy rate compared with cleavage-stage FET.
PMID:34934982 | PMC:PMC8655396 | DOI:10.1016/j.xfre.2021.06.010
