February 7, 2008
Laurie Barclay, MD


Acupuncture has been associated with statistically and clinically significant improvements in pregnancy rates resulting from the embryo transfer process, according to the results of a systematic review and meta-analysis published online February 7 in the British Medical Journal. In China, acupuncture has been used for centuries to help control the female reproductive system.

"Firstly, acupuncture may mediate the release of neurotransmitters, which may in turn stimulate secretion of gonadotrophin releasing hormone, thereby influencing the menstrual cycle, ovulation, and fertility," write Eric Manheimer, from the University of Maryland School of Medicine in Baltimore, and colleagues. "Secondly, acupuncture may stimulate blood flow to the uterus by inhibiting uterine central sympathetic nerve activity. Thirdly, acupuncture may stimulate the production of endogenous opioids, which may inhibit the central nervous system outflow and the biological stress response."

The goal of this systematic review and meta-analysis of randomized controlled trials was to assess the effect of acupuncture given with embryo transfer on the rates of pregnancy and live birth among women undergoing in vitro fertilization.

Using Medline, Cochrane Central, Embase, Chinese Biomedical Database, hand-searched abstracts, and reference lists, the authors identified randomized controlled trials comparing needle acupuncture given within 1 day of embryo transfer vs sham acupuncture or no adjuvant treatment, with reported outcomes of clinical pregnancy, ongoing pregnancy, and/or live birth.

For all of the included trials, the investigators contributed additional data, such as live birth rate, that were not included in the original publication(s). Two reviewers independently determined study eligibility, evaluated methodological quality of the included trials, and extracted outcome data.

All randomized patients (1366 women enrolled in 7 trials) were included in the meta-analyses.

Clinical factors were relatively homogeneous among the included studies. For the primary analysis, trials with sham acupuncture and no adjuvant treatment were pooled as controls.

Administering acupuncture with the embryo transfer process was linked to significant and clinically relevant improvements in clinical pregnancy (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.27 2.14; number needed to treat [NNT], 10 [95% CI, 7 17]; 7 trials), ongoing pregnancy (OR, 1.87; 95% CI, 1.40 2.49; NNT, 9 [95% CI, 6 15]; 5 trials), and live birth (OR, 1.91, 95% CI, 1.39 2.64; NNT, 9 [95% CI, 6 17]; 4 trials).

Outcome data on live births were not available for 3 of the included trials. Therefore, the reviewers suggest that the pooled OR for clinical pregnancy more accurately represents the true combined effect from these trials than does the OR for live birth. These findings were robust to sensitivity analyses on study validity variables.

When using a prespecified subgroup analysis including only the 3 trials with the higher rates of clinical pregnancy in the control group, there was a smaller nonsignificant benefit of acupuncture (OR, 1.24; 95% CI, 0.86 1.77).

"Current preliminary evidence suggests that acupuncture given with embryo transfer improves rates of pregnancy and live birth among women undergoing in vitro fertilization," the reviewers write. "Additional randomised trials are needed to quantify findings further and investigate the relation between baseline rate of pregnancy and the efficacy of adjuvant acupuncture."

Limitations of the meta-analysis include heterogeneity of baseline rates across trials, possible publication and "hypothesis" (orientation) biases, and inclusion of 3 studies presented only as abstracts.

"If acupuncture increased the likelihood of success of an individual cycle, then the need for a subsequent cycle would be reduced, and overall costs would be decreased," the reviewers conclude. "Even if such increases were small, and, for example, 17 patients needed to be treated with acupuncture to bring about one additional pregnancy (that is, the lowest range of our 95% confidence interval), an acupuncture cointervention may still be cost effective, considering the negligible costs of two to four sessions of acupuncture, relative to the high costs of in vitro fertilisation."

Two of the reviewers were funded by the National Center for Complementary and Alternative Medicine of the US National Institutes of Health. The authors have disclosed no relevant financial relationships.

BMJ. Published online February 7, 2008.