The Timing and Dose Effect of Acupuncture on Pregnancy Outcomes for Infertile Women Undergoing In Vitro Fertilization and Embryo Transfer: A Systematic Review and Meta-Analysis

Background: Women undergoing in vitro fertilization and embryo transfer (IVF-ET) often utilize acupuncture to enhance pregnancy outcomes. Yet, the optimal timing for acupuncture sessions and the relationship between dosage and effect remain uncertain. Objectives: To investigate the impact of the timing and dosage of acupuncture on pregnancy outcomes, drawing on existing research. Methods: A comprehensive search of eight databases was conducted from their inception to January 14th, 2023, without restrictions on language. Only randomized controlled trials comparing acupuncture with either sham acupuncture or no adjuvant treatment were selected for inclusion. This meta-analysis assessed the efficacy of acupuncture in IVF-ET, analyzing the influence of varied timing and dosage on pregnancy outcomes. Subgroup analyses were undertaken to address any heterogeneity across the studies. Results: A total of 38 RCTs involving 5,991 participants were analyzed. In infertile women undergoing IVF fresh cycles, acupuncture performed during controlled ovarian hyperstimulation (COH) significantly increased the clinical pregnancy rate (CPR) (relative risk [RR] = 1.33, 95% confidence interval [CI]: 1.07-1.65, p = 0.01), whereas acupuncture administered either before COH or on the day of ET did not demonstrate reproductive benefits. Regarding frozen cycles, acupuncture before freeze-thaw embryo transfer (FET) significantly enhanced the CPR (RR = 1.71, 95% CI: 1.36-2.16, p < 0.00001) and live birth rate (LBR) (RR = 2.40, 95% CI: 1.20-4.79, p = 0.01). Improvements in CPR were observed across all dosage groups, but only the high-dosage group showed a significant increase in LBR (RR = 1.75, 95% CI: 1.05-2.92, p = 0.03). Conclusions: Timing and dosage of acupuncture are crucial factors affecting pregnancy outcomes in IVF-ET. For women undergoing IVF fresh cycles, acupuncture during COH yielded more significant reproductive benefits. In addition, acupuncture before freeze-thaw embryo transfer (FET) was associated with improved pregnancy outcomes in frozen cycles. Furthermore, higher dosages of acupuncture were linked to more favorable outcomes.