Aims:
To assess the benefits and harms of day 5 embryo biopsy, in comparison to day 3 biopsy, in preimplantation genetic testing for monogenic defects (PGT-M).
Methods:
Searches of electronic bibliographic databases were performed to identify randomised controlled trials. Hand searches of grey literature such as trial registers, relevant journals, Google scholar, and published conference abstracts were also performed.
We used standard methodological procedures recommended by Cochrane.
The primary review outcomes were live births and miscarriages.
Outcomes were calculated per woman randomised and were reported as odds ratios with 95 % confidence intervals.
Results:
We are uncertain whether day 5 embryo biopsy, compared to day 3 biopsy, has an effect on live births as only one study was included in the analysis and the confidence interval was wide and crossed the line of no effect (OR 1.50, 95% CI 0.26 to 8.82, 1 RCT, 20 women; very low-certainty evidence) . It is also uncertain whether day 5 embryo biopsy has an effect on miscarriages (OR 3.32, 95 % CI 0.12 to 91.60, 1 RCT, 20 women; very low-certainty evidence). Other secondary outcomes which were assessed in this review were viable intrauterine pregnancies, ectopic pregnancies, stillbirths and termination of pregnancies. The evidence was uncertain for all of these outcomes. We could not reach a conclusion regarding gestational age at birth, birthweight, neonatal mortality and major congenital anomaly as no studies reported data suitable for analysis.
Conclusion:
We are uncertain if there is a difference in live births or miscarriages between day 5 and day 3 embryo biopsy for PGT-M. The results should be interpreted with caution, as the evidence was of very-low certainty, and further studies are needed to confirm findings.