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Risk of placenta accreta spectrum in fresh versus natural, stimulated and programmed cycle frozen-thawed embryo
Tomoyuki Fujita1, Toshiyuki Yoshizato2, Kenta Murotani3
1Mizuho Internal Medicine and Ladies Clinic, Nogata, Japan; Department of Obstetrics and Gynaecology, Kurume University School of Medicine, Kurume, Japan.
Research Question:
How does the risk of placenta accreta spectrum (PAS) in pregnancies from natural cycle (NC-FET), stimulated cycle (SC-FET) and programmed cycle (PC-FET) frozen-thawed embryo transfers compare with that in fresh embryo transfer?
Design:
A total of 174,591 embryo transfer cycles resulting in singleton live births were obtained from the Japanese assisted reproductive technology (ART) registry from 2017 to 2020. A multivariate logistic regression model compared the risk of PAS across different embryo transfer methods. Adjusted factors were maternal age at embryo transfer, indication for ART, number and stage of embryos transferred, use of assisted hatching, presence of placenta praevia and mode of delivery.
Results:
The incidence of PAS was 0.16% (39/23,827), 0.17% (66/37,787), 0.14% (11/8,143) and 1.48% (1,549/104,834) for fresh embryo transfer, NC-FET, SC-FET and PC-FET, respectively. PC-FET carried a higher risk of PAS versus fresh embryo transfer (adjusted odds ratio [aOR] 9.12, 95% confidence interval [CI] 6.54-12.73), whereas there was no significantly increased risk with NC-FET and SC-FET. Subgroup analyses revealed that, for single cleavage-stage embryo transfer, PC-FET was associated with a higher risk of PAS versus fresh embryo transfer (aOR 11.19, 95% CI 6.55-19.11). NC-FET and SC-FET showed no significantly increased risk. For single-blastocyst transfer, PC-FET carried a higher risk of PAS versus fresh embryo transfer (aOR 5.44, 95% CI 3.26-9.09), whereas NC-FET and SC-FET had a similar risk to fresh embryo transfer.
Conclusions:
PC-FET carried a higher risk of PAS than fresh embryo transfer, while NC-FET and SC-FET did not. When planning embryo transfer reproductive physicians should recognize that PC-FET is a potential risk factor for PAS.
