Does maternal age affect assisted reproduction technology success rates after euploid embryo transfer? A systematic review and meta-analysis

Importance: Maternal age-related embryo aneuploidy is considered the most significant limiting factor for a favorable outcome after assisted reproduction technology (ART) procedures. Thus, preimplantation genetic testing for aneuploidies has been proposed as a strategy to genetically evaluate embryos before transfer to the uterus. However, whether embryo ploidy justifies all the aspects of age-related fertility decline remains controversial.

Objective: To investigate the effect of different maternal ages on ART success rates after transfer of euploid embryos.

Data sources: ScienceDirect, PubMed, Scopus, Embase, the Cochrane library, Clinicaltrials.gov, EU Clinical Trials Register, and World Health Organization International Clinical Trials Registry were searched from inception until November 2021 using combinations of relevant keywords.

Study selection and synthesis: Observational and randomized controlled studies were included if they investigated the impact of maternal age on ART outcomes after the transfer of euploid embryos and reported frequencies of women achieving ongoing pregnancy or live birth.

Main outcomes: The ongoing pregnancy rate or live birth rate (OPR/LBR) after euploid embryo transfer comparing women <35 vs. women ≥35 years old was the primary outcome. Secondary outcomes included implantation rate and miscarriage rate. Subgroup and sensitivity analyses were also planned to explore the sources of inconsistency among studies. The quality of studies was assessed using a modified version of the Newcastle-Ottawa Scale, and body of evidence was evaluated using the Grading of Recommendations Assessment Development and Evaluation working group methodology.

Results: A total of 7 studies were included (n = 11,335 ART embryo transfers of euploid embryos). A higher OPR/LBR (odds ratio, 1.29; 95% confidence interval [CI], 1.07-1.54; I² = 40%) in women aged <35 years than in women ≥35 with a risk difference equal to 0.06 (95% CI, 0.02-0.09) was found. In line, implantation rate was higher in the youngest group (odds ratio, 1.22; 95% CI, 1.12-1.32; I² = 0%). A statistically significant higher OPR/LBR was also found comparing women aged <35 to women 35-37, 38-40, or 41-42. A gradient relationship between age and OPR/LBR could be observed in proportion meta-analysis, especially if restricted to studies with low risk of bias.

Conclusion and relevance: Increasing maternal age is associated with a decline in ART success rates independent of embryo ploidy. This message contributes to an appropriate patient's counseling before starting preimplantation genetic testing for aneuploidies procedures.

Prospero registration number: CRD42021289760.