A study failing to determine significant benefits from assisted hatching: patients selected for advanced age, zonal thickness of embryos, and previous failed attempts.
OBJECTIVE
Pregnancy and implantation rates after mechanical assisted hatching (AH) in patients aged > or = 38 years, with embryos > or = 15 microns in zonal thickness and two or more failed attempts, were assessed at two infertility centers using fresh and frozen embryo transfer (FET) cycles.


METHODS
AH was performed on 3-day-old embryos. Spare embryos cryopreserved at the two-pronucleus stage were subjected to AH after 2 days of culture and transferred to artificially prepared uteri.


RESULTS
In fresh cycles, no significant differences in pregnancy rates (clinical and ongoing) and implantation rates were observed between the AH and the controls for all three selected patient groups (Centers 1 and 2). In FET cycles, AH tended to give poor results for > or = 38 year olds (clinical pregnancy rates of 0 and 5.0% with AH vs 13.3 and 16.7% for controls at Centers 1 and 2, respectively). With AH, embryos with thick zonae implanted to the same extent as those in the control group and achieved pregnancies for patients with multiple failures (four to six attempts for some) in both fresh and FET cycles.


CONCLUSIONS
AH failed to show significant benefits in all three patient groups. A larger study group may confirm the effects of AH on frozen/thawed embryos and outcomes for multiple failure cases.
Department of Obstetrics and Gynaecology, Chulalongkorn University, Chulalongkorn Hospital, Bangkok, Thailand.
W R
WR
Edirisinghe
V
V
Ahnonkitpanit
S
S
Promviengchai
S
S
Suwajanakorn
K
K
Pruksananonda
V
V
Chinpilas
P
P
Virutamasen
D000022:Abortion, Spontaneous; D000328:Adult; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D004622:Embryo, Mammalian / Q000166:cytology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007247:Infertility, Female; D008423:Maternal Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D018566:Pregnancy, High-Risk; D011272:Pregnancy, Multiple; D017211:Treatment Failure