Seven RCTs (n=1,366) were included in the review. The sample sizes ranged from 103 to 300 participants.
The trials were generally of a high quality in terms of randomisation procedures and follow-up of the participants. Losses to follow-up occurred in only 2 trials. Although no data were supplied, the authors reported that there was no evidence to suggest the existence of small studies with negative results that were unpublished or not identified.
Acupuncture treatment resulted in a statistically significant increase in the number of cases of clinical pregnancy (7 trials; OR 1.65, 95% CI: 1.27, 2.14, p=0.0002), ongoing pregnancy (5 trials; OR 1.87, 95% CI: 1.40, 2.49, p<0.0001) and live birth (4 trials; OR 1.91, 95% CI: 1.39, 2.64, p<0.0001). Of the 9 subgroup analyses, only the analysis restricted to the 3 trials with higher rates of clinical pregnancy in the control group suggested a smaller, non significant benefit of acupuncture (OR 1.24, 95% CI: 0.86, 1.77).
The numbers-needed-to-treat were 10 for clinical pregnancy, 9 for ongoing pregnancy and 9 for live birth.
Little evidence of heterogeneity was found for clinical pregnancy (I2=16%), ongoing pregnancy (I2=0%) and live birth (I2=0%).
No significant adverse effects were reported in the 2 trials that assessed this outcome.