This study was conducted at the University of North Carolina at Chapel Hill (UNC) Family Medicine Center from February 2005 to March 2007. The study protocol was approved by the biomedical Institutional Review Board at the UNC School of Medicine, and all subjects were provided informed written consent to participate on their date of enrollment.
Women were eligible for enrollment if they were nulliparous, between 38 and 41 weeks of gestation, able to communicate in English, and at least 18 years old. Exclusion criteria included uncertain dating as described by the American College of Obstetricians and Gynecologists (ACOG) induction criteria20
, transportation difficulties, breech presentation, or a previous inability to tolerate acupuncture.
Eligible subjects were identified through prenatal chart review and through web-based advertising in the local community. Interested and eligible subjects were scheduled for an initial visit, at which time consent was obtained, subjects were randomized, and the first acupuncture treatment was performed for subjects allocated to either of the acupuncture arms. Appointments for four additional acupuncture sessions were scheduled at times convenient for the subject during this visit.
Subjects were randomly allocated to one of three study arms: Traditional Chinese Medicine (TCM) acupuncture, sham acupuncture, or no acupuncture. Study arm assignment was determined by using a list of random numbers generated using Stata (v8, Statacorp, College Station, TX) with equal proportions of blocks of two and four. A consecutively numbered, sealed, manila envelope containing the study arm assignment was opened by the principal investigator for each participant after all entry criteria were confirmed, and after written informed consent was obtained. Subjects were allocated to receive either TCM acupuncture along with routine prenatal care (TCM acupuncture group), sham acupuncture along with routine prenatal care (sham acupuncture group) or routine prenatal care alone (usual care group). Participants were told they would be receiving either TCM or sham acupuncture or no treatment. Prenatal care providers and subjects were masked to the treatment arm assignment if they were receiving acupuncture (TCM or sham acupuncture) but not if they were in the usual care group.
Acupuncture treatments were administered at the UNC Family Medicine Center (FMC) for up to a maximum of five treatments over a two-week period. Acupuncture was performed by one of two licensed acupuncturists (ACR and WC). Acupuncture treatments consisted of the insertion of sterile, single-use, disposable Seirin J-type acupuncture needles (0.16 × 30 mm for hand and leg points, 0.24 × 40 mm for back points). True acupuncture points included LI4, SP6, BL32, and BL54 which are located on the hands, legs, and lower back (see ), and needles were advanced or manipulated until ‘deqi’ was elicited. Sham acupuncture points included non-acupuncture points in the hands, legs, and lower back, and needle insertion at these points was shallow (see ). Needles were inserted at all points bilaterally and retained for 30 minutes for both groups. This treatment regimen was devised based on a clinical reference manual commonly used in Chinese acupuncture training and treatment.21
No individualized treatments were performed. All subjects received routine prenatal care as provided by their regular care providers.
Acupuncture points for TCM and sham treatments.
The primary outcome measure was time from enrollment (first acupuncture treatment) to time of delivery. Patients receiving either TCM or sham acupuncture were treated within 30 minutes of enrollment. Time of delivery was established by chart review whenever possible or by phone call to the study participant. A sample size of 30 subjects per group was estimated a priori to provide 82% power to detect a 3-day difference between groups with a two-tailed alpha of 0.05. Statistical analyses were performed using STATA software (v9.2, Statacorp, College Station, TX).
Secondary outcome measures included rates of inpatient induction for postterm pregnancy, spontaneous rupture of membranes (SROM), c-section, assisted delivery, chorioamnitis, endometritis, post-partum hemorrhage or uterine atony, maternal length of stay (LOS), intrapartum fetal distress, and neonatal outcomes (e.g., Apgar scores, post -delivery oxygen requirement). All charts were reviewed by an investigator who was blinded to treatment arm assignment throughout the data abstraction process.
We used ANOVA to compare means of continuous variables, Student’s t-test for pairs, and chi-squared tests to compare categorical outcomes except when the expected number of values per cell was less than five, in which case Fisher’s exact test was used. Survival analysis was performed using the Kaplan–Meier test for equality of survivors; spontaneous labor was used to define failure; survival time was defined as the time from enrollment to delivery. The log-rank test was used to compare Kaplan-Meier curves. Results were considered statistically significant for p-values less than or equal to 0.05. Analyses were performed according to the intent-to-treat principle.