Jinli Ding1, Tailang Yin1, Yi Zhang1, Danni Zhou1, Jing Yang2. 1. Reproductive Medical CentreRenmin Hospital of Wuhan UniversityWuhanChina; Hubei Clinic Research Centre for Assisted Reproductive Technology and Embryonic DevelopmentWuhanChina. 2. Reproductive Medical CentreRenmin Hospital of Wuhan UniversityWuhanChina; Hubei Clinic Research Centre for Assisted Reproductive Technology and Embryonic DevelopmentWuhanChina. Electronic address: dryangqing@hotmail.com.
Abstract
RESEARCH QUESTION: Is blastocyst transfer (BT) associated with a higher offspring secondary sex ratio and monozygotic twinning (MZT)? DESIGN: A systematic search of PubMed/MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar databases was carried out for studies published between 1995 and May 2017 using relevant keywords and a meta-analysis performed on selected studies. The analysis was performed using Stata 12.0; odds ratios (OR) and 95% confidence intervals (CI) were used to assess the results for binary studies. Subgroup analyses and meta-regression were also conducted. RESULTS: Twenty-six studies published between 2001 and May 2017 (sex ratio: 13, MZT: 12, and both sex ratio and MZT: 1) were identified. The analysis showed a significantly higher M/F ratio at birth (OR = 0.89, 95% CI: 0.86 to 0.93, I2 = 19.8%) and a higher risk of MZT (OR = 0.37, 95% CI: 0.22 to 0.60, I2 = 75.2%) after BT compared with cleavage-stage embryo transfer (CT). Furthermore, a subgroup analysis was performed based on studies published after 2009; results were found to be consistent with the 2009 meta-analysis. CONCLUSIONS: This meta-analysis provides an update and stronger evidence to support the observation that BT is associated with a higher proportion of males and an increased risk of MZT. In clinical practice, these BT-associated neonatal outcomes should be taken into account when counselling infertility patients.
RESEARCH QUESTION: Is blastocyst transfer (BT) associated with a higher offspring secondary sex ratio and monozygotic twinning (MZT)? DESIGN: A systematic search of PubMed/MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar databases was carried out for studies published between 1995 and May 2017 using relevant keywords and a meta-analysis performed on selected studies. The analysis was performed using Stata 12.0; odds ratios (OR) and 95% confidence intervals (CI) were used to assess the results for binary studies. Subgroup analyses and meta-regression were also conducted. RESULTS: Twenty-six studies published between 2001 and May 2017 (sex ratio: 13, MZT: 12, and both sex ratio and MZT: 1) were identified. The analysis showed a significantly higher M/F ratio at birth (OR = 0.89, 95% CI: 0.86 to 0.93, I2 = 19.8%) and a higher risk of MZT (OR = 0.37, 95% CI: 0.22 to 0.60, I2 = 75.2%) after BT compared with cleavage-stage embryo transfer (CT). Furthermore, a subgroup analysis was performed based on studies published after 2009; results were found to be consistent with the 2009 meta-analysis. CONCLUSIONS: This meta-analysis provides an update and stronger evidence to support the observation that BT is associated with a higher proportion of males and an increased risk of MZT. In clinical practice, these BT-associated neonatal outcomes should be taken into account when counselling infertilitypatients.