Interpretation
Our review suggested that the pooled CPR and LBR from all the acupuncture group were significantly higher than that from all the control group (p < 0.001). It was consistent with the studies reported by Manheimerand E et al (2008) (8) and Zheng CH et al (2012) (9). However, when restriction to only low risk of bias studies, there was no benefit of TA method on CPR and LBR. It suggested that we should caution against the benefits of TA being overstated. Of note, when only low risk of bias studies were included, a change to a non-significant effect did occur for TEAS. Because of the later published time, TEAS intervention did not involve in the existed reviews and this was the first time to report the pooled effect of TEAS. The results of TEAS is of great clinically significance for IVF, based on its advantages of noninvasiveness and painlessness, TEAS may have better application potential and be more acceptable. The safety of TEAS may be better than TA, because the MR was not significant between TEAS and no treatment. Meanwhile, unlike TA method, sham TEAS is easy to be implemented by ”pseudo-percutaneous patch” method.
In our meta-analysis, TA did not increase the CPR compared with sham acupuncture, whether or not the sham needles were penetrated. This was consistent with a growing concern that sham acupuncture was not an inert control and may result in the difference between intervention and sham group not being significant. Regardless of either true or sham acupuncture was used, they could both produce specific effects and non-specific effects. The non-specific effects between treatment and sham acupuncture may be reduced to the greatest extent through blind and random methods. Therefore, in order to improve the reliability, an appropriate control group should be selected by the specific study objective like examining the pragmatic or comparative effectiveness (22).
In our study, differences were seen when different acupuncture sessions were analyzed. A dosage of ≥3 times for TA and TEAS were both associated with statistically significant improvement on CPR and LBR. Many trials tended to use two or a maximum of three sessions of acupuncture, such as “Paulus acupuncture protocol” performed just twice with one before and another after ET (57). Insufficient acupuncture dosage in IVF has been a common opinion (78). Some investigators suggested that a clinically valid dosage of acupuncture should be more than six acupuncture sessions and at least choose four to ten (or more) acupuncture points in each session (79). Further study should explore the specific effective dose of acupuncture treatment.
Our review analyzed all common acupuncture types in IVF treatment based on the most comprehensive trials. The results of TEAS supply a superior and safe choice for patients and physicians, especially compared with manual acupuncture, its advantages of noninvasiveness and easier administration partly reduce the involvement of many confounding factors cause by acupuncturists. Therefore, it may be a promising IVF adjunctive treatment and has broader application after being validated by strict RCTs. We also found that less than 35 years, treatment with ≥3 sessions, acupuncture before the ET, no RIF history and lower baseline pregnancy rates were associated with increases in CPR and LBR. These results were greatly helpful for the design of further acupuncture treatment trials in IVF. In addition, LBR should be considered as a primary outcome of the further IVF meta-analysis study. It was undeniable that clinical pregnancy was a major breakthrough in medicine, but for infertile couples, “take-home” babies were the most important long-term and ultimate outcome of interest (25, 26). Moreover, the efficacy was significant just for CPR rather than LBR, which may indicate a higher risk of miscarriage. This not only increased the patients’ economic burden, but also further resulted in psychological consequences.