Acupuncture may help some women conceive through in-vitro fertilization, according to a new analysis on past studies, however the true benefit remains unclear.

Acupuncture is the traditional Chinese medicinal needle treatment for a range of health problems.

Ten years ago, German researchers reported that acupuncture seemed to improve pregnancy rates in women undergoing IVF, but since then research on the topic has shown conflicting results.

German studies have also showed in a series of imaging experiments that pain centers in participants’ brains were significantly calmer after researchers applied a few short electrical zaps to acupuncture needles that were pinned to the skin on their ankles.

In the new meta-analysis, published in the journal Fertility and Sterility, Chinese researchers looked at the overall picture of the effectiveness of acupuncture and IVF by combing results of past studies.

Dr. Cui Hong Zheng and colleagues at Tongji Medical College looked at 24 small clinical trials testing the effects of acupuncture in women undergoing IVF that consisted of a wide variety of acupuncture techniques like needle acupuncture, electro-acupuncture and laser acupuncture.

Chinese researchers found that women who had acupuncture generally had a slightly higher pregnancy rate, but not a higher birth rate than women who did not have the therapy.

Researchers noted that many of the studies differed in what they used as their control variable. When researchers excluded five studies that used blunt needles as a control, the results of the women who received acupuncture seemed to have more improvements.

Zheng justified removing the experiments that labeled “blunt-needle” acupuncture as control or placebo variables because the treatment is still acupuncture and may actually have similar effects to the real thing.

The researchers said that when the five trials were dropped, 41 percent of the women became pregnant versus 37 percent of those who did not have the treatment.

Researchers also looked at birth rates and found that 35 percent of the women who received acupuncture had a baby compared with 25 percent of women in the control groups.

Researchers are unsure as to why acupuncture may help a woman conceive with IVF, but they note that there is some evidence that suggests needle stimulation may improve blood flow to the uterus.

Scientists are still researching if acupuncture treatments could yield a uterine wall to be more receptive to the embryo.

Acupuncture is generally safe with little side effects like bruising at the needle site. The cost varies widely.

The study is published online in the Fertility and Sterility on January 12, 2012.