LAS VEGAS – Women who had cesarean delivery and received a nonopioid pain control regimen at hospital discharge had lower pain scores by 4 weeks post partum than those who also received opioids, according to study results shared during a fellows session at the meeting presented by the Society for Maternal-Fetal Medicine.
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At 2-4 weeks post partum, the mean pain score on a visual analog scale (VAS) was 12/100 mm for women on the nonopioid regimen, compared with 16/100 mm for women who received opioids, using an intention-to-treat analysis. The median pain score for those in the nonopioid arm was 0, compared with 6 for those in the opioid arm.
The findings surprised Jenifer Dinis, MD, a maternal-fetal medicine fellow at the University of Texas, Houston, and her collaborators, because they had hypothesized merely that the two groups would have similar pain scores 2-4 weeks after delivery.
Although women in the nonopioid arm were able to obtain a rescue hydrocodone prescription through the study, and some women obtained opioids from their private physician, they still used less than half as much opioid medication as women in the opioid arm (21 versus 43 morphine milligram equivalents, P less than .01).
However, women in the nonopioid arm did not use significantly more ibuprofen or acetaminophen, and there was no difference in patient satisfaction with the outpatient postpartum analgesic regimen between study arms. Somnolence was more common in the opioid arm (P = .03); no other medication side effects were significantly more common in one group than the other.
Overall, 22 of 76 (29%) women in the nonopioid arm took any opioids after discharge, compared with 59/81 (73%) in the opioid arm (P less than .01).
After cesarean delivery, the 170 participating women had an inpatient pain control regimen determined by their primary ob.gyn., Dr. Dinis said in her presentation. Patients were randomized 1:1 to their outpatient analgesia regimens on postoperative day 2 or 3, with appropriate prescriptions placed in patient charts. Participants received either a nonopioid regimen with prescriptions for 60 ibuprofen tablets (600 mg) and 60 acetaminophen tablets (325 mg), or to an opioid regimen that included ibuprofen plus hydrocodone/acetaminophen 5 (325 mg) 1-2 tablets every 4 hours.
Pain scores were assessed between 2 and 4 weeks after delivery, either at an in-person appointment or by means of a phone call and a provided email link.
The single-site study was designed as a parallel-group equivalence trial, to show noninferiority of one pain control regimen over the other. Women between the ages of 18 and 50 years were included if they had a cesarean delivery; both English- and Spanish-speaking women were enrolled.
Allowing for attrition and crossover, Dr. Dinis and her colleagues enrolled 85 patients per study arm to achieve sufficient statistical power to detect the difference needed. The investigators planned both an intention-to-treat and a per-protocol analysis in their registered clinical trial.
Postpartum pain assessments were not obtained for 12 patients in the nonopioid group, and 9 in the opioid group, leaving 73 and 76 patients in each group for the per-protocol analysis, respectively.
At baseline, patients were a mean 28 years old, and a little over a quarter (28%) were nulliparous. Participants were overall about half African American and 34%-40% Hispanic. Over half (62%-72%) received Medicaid; most women (62%-75%) had body mass indices of 30 kg/m2 or more.
The mean gestational age at delivery was a little more than 36 weeks, with about half of deliveries being the participant’s first cesarean delivery. About 90% of women had a Pfannenstiel skin incision, with a low transverse uterine incision.
Patients were aware of their allocation, and the study results aren’t applicable to women with opioid or benzodiazepine use disorder, she noted. However, the study was pragmatic, included all types of cesarean deliveries, and was adequately powered to detect “the smallest clinically significant difference.”
Dr. Dinis reported no outside sources of funding and no conflicts of interest.
SOURCE: Dinis J et al. Am J Obstet Gynecol. 2019 Jan;220(1):S34, Abstract 42.