Clinical rationale for cryopreservation of entire embryo cohorts in lieu of fresh transfer.
Recent dramatic increases in success rates with frozen-thawed embryo transfer (FET) are encouraging, as are numerous findings of several reduced risks with FET when compared with fresh transfer. These reduced risks include low birth weight and prematurity, among others. However, FET is also associated with increased risks of macrosomia and large for gestational age. There have been reports of greater implantation and pregnancy rates with FET than with fresh autologous embryo transfer, suggesting superior endometrial receptivity in the absence of ovarian stimulation. As cryo-technology evolves, there is potential for further increase in FET success rates, but for now it may be best to follow an individualized approach, balancing fresh transfer and embryo cohort cryopreservation options while considering patient characteristics, cycle parameters, and clinic success rates.
Fertility Center of Las Vegas, Las Vegas, Nevada; Department of Obstetrics and Gynecology, University of Nevada School of Medicine, Las Vegas, Nevada. Electronic address: bsshapiro@aol.com.
Bruce S
BS
Shapiro
Fertility Center of Las Vegas, Las Vegas, Nevada; Department of Obstetrics and Gynecology, University of Nevada School of Medicine, Las Vegas, Nevada.
Said T
ST
Daneshmand
Fertility Center of Las Vegas, Las Vegas, Nevada; Department of Obstetrics and Gynecology, University of Nevada School of Medicine, Las Vegas, Nevada.
Forest C
FC
Garner
Fertility Center of Las Vegas, Las Vegas, Nevada.
Martha
M
Aguirre
Fertility Center of Las Vegas, Las Vegas, Nevada.
Cynthia
C
Hudson
D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000009:adverse effects; D004622:Embryo, Mammalian / Q000187:drug effects; D005260:Female; D005298:Fertility; D005299:Fertility Agents / Q000009:adverse effects; D005307:Fertilization in Vitro / Q000009:adverse effects; D006801:Humans; D007246:Infertility / Q000503:physiopathology / Q000628:therapy*; D010062:Ovulation Induction / Q000009:adverse effects; D011247:Pregnancy; D018873:Pregnancy Rate; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
D005299:Fertility Agents
In vitro fertilization; embryo cryopreservation; frozen embryo transfer; ovarian stimulation; perinatal risk