High pregnancy rates can be achieved after freezing and thawing human blastocysts.
Fertil Steril
; 82(5): 1418-27, 2004 Nov.
Article
em En
| MEDLINE
| ID: mdl-15533370
ABSTRACT
OBJECTIVE:
To examine the results of a 3-year trial using blastocyst cryopreservation to limit multiple pregnancy and optimize overall pregnancy per cycle.DESIGN:
Retrospective clinical evaluation of pregnancy rates after freezing and thawing human blastocysts.SETTING:
Tertiary-care academic center. PATIENT(S) Seven hundred fifty-three different patients treated in 783 IVF cycles with blastocysts frozen from July 2000 to June 2003. INTERVENTION(S) Two thousand, two hundred fifty-nine blastocysts were frozen in cycles in which only blastocysts were cryopreserved (cycles with pronuclear stage oocytes or pre-embryos also cryopreserved were excluded from the analysis). Of these, 628 (27.6%) were thawed in 218 cycles. MAIN OUTCOME MEASURE(S) Pregnancy rate per cycle with thaw. RESULT(S) Four hundred seventy-nine (76.3%) blastocysts survived thawing, and 440 (92.0%) were transferred after exhibiting evidence of survival (most commonly, blastocoele reexpansion). In cycles with a thaw, 211 (96.8%) of 218 underwent intrauterine transfer. An average of 2.09 blastocysts was transferred per replacement. One hundred twenty-five (59.2%) clinical pregnancies were established, which included 23 sets of twins and 5 triplet gestations. Two sets of monozygotic twins were identified after the replacement of a single thawed blastocyst (1.6%). The age of the patient at the time of cryopreservation (<37 years) was an important factor in the establishment of clinical and ongoing pregnancy. The mode of ovarian stimulation, replacement method, and whether blastocysts were frozen on day 5 or day 6 of development did not demonstrate clinical significance. CONCLUSION(S) Cryopreserved and thawed blastocysts demonstrated a similar potential for implantation when compared with fresh pre-embryos on day 3. On the basis of these results, the blastocyst stage of development appears to be optimal for clinical freeze-thaw trials.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Blastocisto
/
Criopreservação
/
Taxa de Gravidez
Tipo de estudo:
Observational_studies
/
Prognostic_studies
Limite:
Adult
/
Female
/
Humans
/
Pregnancy
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article