The effects of acupuncture on rates of clinical pregnancy among women undergoing in vitro fertilization: a systematic review and meta-analysis

This study is the most comprehensive systematic review and meta-analysis on the effects of acupuncture as an adjunct treatment to in vitro fertilization (IVF), analyzing 16 randomized clinical trials involving 4,021 participants from different countries. The main objective was to quantify the overall effects of acupuncture on clinical pregnancy rates in women undergoing IVF and to identify factors that could explain differences between studies. The methodology was rigorous, including searches in multiple medical databases, direct contact with all authors of the included studies to obtain unpublished data, and analysis of 11 prespecified variables to investigate sources of heterogeneity. The researchers separately analyzed studies that used sham acupuncture as a control versus those that used no adjunct treatment.

All included studies evaluated traditional needle acupuncture administered within one day of embryo transfer, with protocols ranging from one to three sessions. The main results showed no statistically significant difference in clinical pregnancy rates when all studies were combined (RR 1.12, 95% CI 0.96-1.31), nor when restricted only to sham-controlled studies or to those with no-treatment control. However, substantial heterogeneity was observed between studies (I²=68%), indicating considerable variability in results. Subgroup analysis revealed a clinically important finding: the baseline pregnancy rate of the clinics was the only statistically significant modifier of the acupuncture effect.

Studies conducted in clinics with lower baseline pregnancy rates (below 32%) showed significant benefits from acupuncture (RR 1.53, 1.28-1.84), while studies in clinics with higher rates demonstrated no benefit (RR 0.90, 0.80-1.01). This variable explained 93% of the heterogeneity between studies. The clinical implications suggest that acupuncture may be more beneficial as an adjunct to IVF in settings where success rates are already lower, possibly because in environments with high success rates, the additional value of complementary interventions is limited. Regarding safety, no serious adverse events associated with acupuncture were reported in the seven studies that described adverse events.

Miscarriage rates were similar between groups. Limitations include the possibility of publication bias, as suggested by the asymmetric funnel plot, where smaller studies tended to show more favorable results. In addition, the analysis of multiple subgroups increases the risk of false-positive findings, and unidentified factors may confound the observed relationship between baseline pregnancy rate and acupuncture efficacy.