Table 1 Characteristic of included studies
Study | Year | Source | Patientor population | Method of data collection | Risk of bias | Outcomes | NOS scoring |
|---|---|---|---|---|---|---|---|
Chambers, et al. (2015) [6] | 2009 to 2012 | National registry | 47370 live deliveries in Australia and New Zealand (day 2/3 vs day 5/6) | Australian and New Zealand Assisted Reproduction Database | Some patients do not have complete information | No increased risk of LBW and PTB resulting from blastocyst transfers compared to cleavage transfers | 8 |
Dar, et al. (2013) [24] | 2001 to 2009 | National registry | 12712 singletons in Canada on a voluntary basis (day 3 vs day 5/6) | Canadian ART Register database | The PTB unadjusted by potential confoundding factors. The women in the blastocyst group were young | Increased risk of preterm birth with day 5/6 transfers | 8 |
Fernando, et al. (2012) [22] | 2004 to 2009 | Single center | 4202 women conceived via IVF/ICSI in Australia (day 2/3/4 vs day 5/6) | Monash IVF patient database | Cleavage stage includes day 4. | No statistically significant difference between transfers on days 5/6 and days 2/3/4 in all maternal and perinatal outcomes | 7 |
Ginstrom Ernstad, et al. (2016) [13] | 2002 to 2013 | National registry | 30566 singletons in Sweden via IVF/ICSI treatments (day 2/3 vs day 5/6) | Swedish Medical Birth Register and the National Patient Register | The number of blastocyst transfers is very low relative to the number of cleavage-stage transfers | Singletons born after blastocyst transfer had a lower risk of LBW and SGA as compared to cleavage-stage transfers. | 8 |
Kalra, et al. (2012) [20] | 2004 to 2006 | National registry | 69039 live deliveries via IVF in U.S. (day 3 vs day5/6) | Society of Assisted Reproductive Technologies database | Women in the blastocyst transfer group were young. No ICSI cycles in the study. | After blastocyst transfers, patients were at an increased risk for PTB and VTPB as compared with cleavage-stage transfer | 9 |
Martin, et al. (2012) [19] | 2002 to 2009 | Single center | 1183 singltons from the hospital of Tours, France (day 2 vs day 5/6) | Forms completed by couples | Forms filled out by couples. | Incresded risk of PTB after blastocyst transfer | 7 |
Oron, et al. (2014) [15]. | December 2008 to December 2012 | Single center | 1543 single embryo transfers in McGill University Health Center, Canada (day 2/3 vs day 5) | In their computerized database | The small number of live births resulting from cleavage and blastocyst embryo transfers. | No increased risk of maternal or neonatal complications in pregnancies resulting from blastocyst embryo transfers | 8 |
Maxwell, et al. (2015) [25] | 2003 to 2012 | Single center | 392 singleton live births via IVF/ICSI at New York University Fertility Center (day 3 vs day 5/6) | In their computerized database | Women were young in the blastocyst group. | No increased risk of PTB and VPTB | 8 |
Zhu, et al. (2014) [21] | January 2009 to June 2012 | Single center | 2929 singletons born at Peking University Third Hospital (day 3 vs day 5/6) | In their computerized database | The number of day 3 transfers was high relative to the number of day 5/6 transfers. No ICSI cycles in the study | No increased risk of SGA | 8 |
Ishihara, et al. (2014) [23] | 2008 to 2010 | National registry | 277042 singletons born in Japan | Japanese ART registry database collected by the Japan Society of Obstetrics and Gynecology | Women were young in the blastocyst transfer group. | Blastocyst transfers were associated with a significantly decreased rate of SGA | 8 |
De Vos, et al. (2015) [27] | April 2004 to December 2009 | Single center | 2098 singleton live births in single center, Belgium (day 3 vs day 5) | In their computerized database | Women were young in the blastocyst group. | The mean singleton birthweights were not different between day 3 embryo transfers and day 5 blastocyst transfers | 8 |
Makinen, et al. (2012) | 2000 to 2010 | Single center | 1079 infants born after treatment at the Family Federation of Finland Fertility Clinic in Helsinki, Finland (day 2/3 vs day 5/6) | In their computerized database | Details about patients were not clearly described. | No increased risk of SGA | 7 |