February 7, 2008 — 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.
