Study | Reason for exclusion |
---|---|
Abdelmassih 2002 | Pooled oocytes and then randomised; no per woman data provided |
Antinori 1996a | Not a randomised controlled trial Mentions randomly selected not randomly allocated |
Antinori 1996b | No randomised comparison between control and assisted hatching groups |
Balaban 2002 | Not randomised No appropriate controls |
Bider 1997 | Not randomised |
Blake 2001 | Not randomised No embryo transfer occurred, so no review outcomes could be measured |
Carter 2003a | No per woman data |
Chao 1997 | Assessment of pregnancy was by HCG only, 14 days after embryo transfer |
Check 1996 | Not randomised Benefits of AH confounded by concurrent assessment of 2 different culture media |
Chen 1999 | Not randomised Benefits of assisted hatching confounded by concurrent assessment of two different culture media |
Cieslak 1999 | Comparison of two types of assisted hatching; no 'no assisted hatching' control group was used More than one cycle per woman |
Cohen 1990 | Not randomised |
Debrock 2011 | Primary outcome was implantation, results per embryo transfer and not per woman |
Demirol 2003 | No pregnancy data provided |
Dirnfeld 2003 | No hatching |
Dokras 1994 | No appropriate outcome measure |
Domitrz 2000 | Benefits of assisted hatching confounded by concurrent assessment of two different culture media |
Ebner 2002 | No per woman data |
Edirisinghe 1999 | Not randomised |
Feng 2009 | Not a prospective study. A retrospective study |
Figueira 2012 | eggs were from egg donors, not the womens' own eggs |
Frydman 2006 | No per woman data |
Gabrielsen 2004 | Pseudo‐randomised (alternate days) |
Grace 2007 | No control. Comparing assisted hatching in good embryos with assisted hatching in poor embryos. |
Hershlag 1999 | Not randomised The control group were from the period 1990 to 1993, while the assisted hatching group were from 1994 to 1996 (historical controls) |
Hiraoka 2009 | No control. Comparing a half thinning versus a quarter thinning. |
Hur 2011 | Not clear if randomised, results appear to be per embryo transfer rather than per woman |
Huttelova 1999 | Not randomised Benefits of AH confounded by concurrent assessment of 2 different culture media |
Komarovsky 2002 | No per women data |
Komarovsky 2003 | No per women data |
Lee 1999 | Not randomised |
Levron 2003 | No per women data |
Ma 2007 | No per women data |
Magli 1998 | No per women data |
Mahadevan 1998 | Not randomised No concurrent controls |
Mansour 2000 | Randomisation by alternate days |
Meldrum 1998 | Not randomised No concurrent controls |
Montag 1999 | Not randomised No concurrent controls |
Nagy 2003 | No per woman data |
Nakayama 1998 | No appropriate outcome measure |
Nakayama 1999 | No per woman data |
Ng 2008 | No control. Compared 2 methods of laser |
Obruca 1994 | Not randomised No concurrent controls |
Olivennes 1997 | No per woman data |
Peterson 2006 | results per embryo transfer only no per woman data |
Rienzi 2002 | Assisted hatching was part of the ICSI method |
Ringler 1999 | It was not clear how many women were included in the study, or for how many cycles (only cycles were mentioned), and a mixture of participants and donated eggs were used for the study |
Schoolcraft 1994 | Not randomised Control and intervention groups recruited at different times |
Shahin 2003 | No per women data |
Sifer 2005 | Per cycle data only No per woman data |
Szell 1998 | Not randomised Benefits of assisted hatching confounded by concurrent assessment of two different culture media |
Tao 1997 | Not randomised Some of the women in the assisted hatching group were randomised, but most were allocated assisted hatching routinely, with no control option |
Tucker 1991 | Not randomised |
Urman 2002 | Alternate randomisation |
Valojerdi 2008 | Inadequate method of randomisation |
Yano 2007 | No per woman data, only per cycle data |
Zech 1998 | Numbers in tables do not add up correctly and the text and tables are contradictory on the age groups used in the prospective part of the study |
Zhang 2009 | Not a prospective study. A retrospective study. |
HCG = human chorionic gonadotropin