Acupressure for Nausea and Vomiting of Pregnancy
January 1999; Volume 1: 9-11
By Adriane Fugh-Berman, MD
Although acupuncture is more widely accepted for pain treatment, the evidence for its effectiveness in treating nausea and vomiting of various etiologies is much stronger than for pain. Stimulation of acupuncture points does not have to be done by needles; finger pressure, electrical stimulation, and heat stimulation (usually by smoldering moxa, a cone or a stick of the compressed herb mugwort) have all been used instead of needles.
There are at least 33 controlled trials of acupuncture point stimulation in the treatment or prevention of nausea and vomiting.1 This plethora of trials is partially due to the extreme ease of performing these trials. Most acupuncture treatments are tailored to individual patients and are highly dependent on practitioner preference points. So, not only would a single practitioner treat different patients with the same disease differently, but different practitioners may choose different points to treat on the same patient.
However, for nausea and vomiting, most practitioners use the same single point, called Neiguan or P6, located two cun below the distal wrist crease, between the palmaris longus and the flexor carpi radialis tendons. A "cun" is a Chinese measurement equaling the width of the interphalangeal joint of the patient’s thumb; two cun equals approximately three finger-breadths. Although other antiemesis points exist, P6 is the most popular. (See Figures 1 and 2.)
The invention of acupressure bracelets by a Chinese sailing enthusiast who suffered from seasickness has made the use of this technique even easier, for both clinical practice and clinical trials. Worn on the wrists, acupressure bracelets are elastic strips that contain a button that presses on the P6 point. Adjusting the bracelets so that the button stimulates the correct point for half the patients and the incorrect point for the control group is an easy way to control trials of nausea and vomiting.
So what is the supporting evidence in using acupoint stimulation for nausea and vomiting of pregnancy? Seven controlled treatment trials and one prevention trial of P6 stimulation for morning sickness have been conducted. All but one showed significant improvement for nausea in the treated group. It is not clear, however, that vomiting is improved by this technique.
Sea Bands (a brand of P6 acupressure bands) have been tested in a number of trials with quite varied methodologies. The most recent (and only negative) trial was a relatively large community-based trial in which 161 symptomatic volunteers were assigned to bands correctly placed, bands incorrectly placed, or no treatment.2 Bands were used for three days and symptoms recorded for two days before and after the intervention. All groups reported decreased nausea and vomiting but there were no significant differences between the groups. Two factors that appear to be different in this trial are the fact that all participants were given information on "non-pharmaceutic interventions" (these are not further described) on the first day of the study; so what was really being tested was whether the use of acupressure bracelets had any additive effect to non-pharmaceutic interventions. Additionally, all participants were allowed to use antiemetics. Although the effect of medication was separately analyzed, the fact remains that subjects were receiving multiple interventions that may well have obscured any benefit of acupressure.
In a small, randomized, crossover trial, eight women with morning sickness used Sea Bands for five days, followed by five days without therapy.3 This group was compared to eight women who had no therapy for five days, followed by five days of acupressure bands. Extent of nausea and vomiting was assessed by patient self-report at baseline, day five, and day 10; acupressure bands significantly reduced morning sickness compared to no intervention. This is not an ideal trial because pa-tients were aware of which days they were being treated.
Two other trials of symptomatic women compared correctly placed with incorrectly placed Sea Bands. Both trials, one with 16 women4 and one with 42 women,5 showed significant reductions in nausea scores.
In a double-blind, controlled trial of 60 women at 7-12 weeks of pregnancy, women were treated in three-day cycles for 12 days.6 Half the time they were treated with active Sea Bands and half the time with a placebo band (which had a blunted button that would not cause adequate pressure on the P6 point). Symptoms were reported according to the Dundee scale. Slight = occasional nausea without vomiting; moderate = daily nausea, no vomiting; troublesome = periodic vomiting with or without nausea; severe = daily nausea and vomiting. More than 60% responded to a Sea Band that pressed on an acupuncture point, while 30% responded to the placebo band. This trial also compared bilateral vs. unilateral stimulation and found no difference between the two.
In another trial, self-administered acupressure was tested. Sixty women with morning sickness were assigned to two groups: one group was taught how to apply acupressure at the P6 point; the other group was taught how to apply acupressure at a placebo point on the palm.7 Nausea was measured by symptom score and improved more in the experimental group than in the controls; however, there was no difference in the frequency or severity of emesis.
Electrical stimulation has also been tested. One crossover trial of 23 women in the first 14 weeks of pregnancy with nausea and/or vomiting used special wristwatch-sized TENS units that delivered a continuous current to P6.8 Each woman used an active device for 48 hours and a deactivated device for 48 hours. The order of use was randomly assigned. This study found improvement in 87% of women receiving active treatment and 43% receiving placebo treatment; the difference was significant. Nausea scores were also significantly better in the treatment group; however, maximum nausea scores did not differ between the two groups. Vomiting was not separately analyzed.
The fascinating part of this study, published in J Repro Med, was the authors’ scrupulous avoidance of any acknowledgment that this was an acupuncture point stimulation study. The term "sensory afferent stimulation" is used in the title and throughout. The words "acupuncture," "acupressure," "P6," or "Neiguan" appear nowhere in the paper; placement of the unit is described as "the volar side of the wrist." Even the references avoid all mention of acupuncture point stimulation studies. One can only surmise that the authors feared any affiliation with alternative medicine enough that they masked what they were actually testing.
Only one prevention study was identified. Three hundred fifty women attending a prenatal clinic were allocated into three groups: One group received no treatment, one group was taught the location of the P6 point and was asked to apply finger pressure for five minutes every four hours on four successive mornings, and one group was told to stimulate a dummy point near the right elbow.9 Each group was asked to record frequency and severity of morning sickness and record the symptoms. Sickness was significantly less in women stimulating the P6 point than in the placebo point or untreated groups. Although reporting rates were equivalent in all three groups, the number of completed forms (the only ones analyzed) differed, with the control group having a higher rate of completed forms.
No trials were identified that tested acupuncture point stimulation for hyperemesis gravidarum. It would be very interesting to see whether the addition of acupoint stimulation to standard treatment makes a difference in hyperemesis gravidarum.
While most of the available evidence supports the use of acupuncture point stimulation to reduce nausea symptoms for patients with morning sickness, there is little evidence that the technique reduces vomiting. For patients with mild-to-moderate morning sickness (especially those for whom nausea predominates over vomiting), this technique is worth a try. Patients can easily learn the location of this point in order to apply finger pressure; another option is acupressure bracelets, which are inexpensive and an easy way to achieve constant stimulation of the point.
1. Vickers AJ. Can acupuncture have specific effects on health? A systematic review of acupuncture antiemesis trials. J R Soc Med 1996;89:303-311.
2. O’Brien B, et al. Efficacy of P6 acupressure in the treatment of nausea and vomiting during pregnancy. Am J Obstet Gynecol 1996;174:708-715.
3. Hyde E. Acupressure therapy for morning sickness. A controlled clinical trial. J Nurse Midwifery 1989;34:171-178.
4. Bayreuther J, et al. A double-blind cross-over study to evaluate the effectiveness of acupressure at pericardium 6 (P6) in the treatment of early morning sickness (EMS). Complement Ther Med 1994;2:70-76.
5. Stone CL. Acupressure wristbands for the nausea of pregnancy. Nurs Pract 1993;18:15-23.
6. de Aloysio D, Penacchioni P. Morning sickness control in early pregnancy by Neiguan point acupressure. Obstet Gynecol 1992;80:852-854.
7. Belluomini J, et al. Acupressure for nausea and vomiting of pregnancy: A randomized, blinded study. Obstet Gynecol 1994;84:245-248.
8. Evans AT, et al. Suppression of pregnancy-induced nausea and vomiting with sensory afferent stimulation. J Reprod Med 1993;38:603-606.
9. Dundee JW, et al. P6 acupressure reduces morning sickness. J R Soc Med 1988;81:456-457.