///2010 Abstract Details
2010 Abstract Details2019-08-03T15:49:10-06:00

Incidence of Chronic Pain after Delivery and Postpartum Spinal Oxytocin Level - Are they related?

Abstract Number: 11
Abstract Type: Original Research

Nichole L Taylor D.O.1 ; James Eisenach M.D.2; Peter H Pan M.D.3

Introduction: Childbirth, whether vaginal or C/S, is a physical trauma, resulting in acute pain. Similar injury from non-obstetric trauma or surgery results in chronic pain in 10-50% of patients(pts)1, yet incidence of chronic pain after delivery(CPAD) seems low & has not been prospectively studied. In rats, neuropathic hypersensitivity was shown to be alleviated in postpartum(PP) period, which was associated with increase lumbar spinal oxytocin level (SOL) & blocked by intrathecal atosiban(oxytocin antagonist)2. We hypothesize that CPAD incidence is low & its mechanism is due to higher PP SOL than non-peripartum counterparts. We designed a 2-part study - a prospective longitudinal cohort to evaluate CPAD incidence & magnitude; & a follow up exploratory descriptive controlled study to compare SOL between PP & non-peripartum pts.

Mehods: To determine CPAD incidence & intensity, 978 pts (304 C/S, 668 SVD) were consented & interviewed within 36 hrs of delivery regarding pain during pregnancy, at & after delivery. Follow up interview was performed at 2, 6 & 12 mo after delivery. Incidence & intensity of chronic pain at 6 & 12 mo were analyzed & compared between delivery modes. In our follow-up SOL study, 12 immediate PP pts (for PP BTL) & 12 comparable non-peripartum pts (not pregnant >1 yr, for GYN surgery) were consented. During spinal anesthesia, a spinal needle was inserted at L3-4/L4-5 level to obtain 1mL spinal fluid. SOL was determined by radioimmunoassay. Pilot data & priori power analysis (α=0.05, 1-β=0.80) suggest minimum gp size of 9 to show a 11 pg/mL difference. Descriptive statistics, ANOVA, Chi-Squares/Fishers exact test & unpaired t-test were used. P<0.05 is significant.

Results: CPAD at 6 & 12 months was low, present in only 1.9%(95%C.I.,1.0, 2.8%) at 6 mo , declining to 0.3%(95%C.I. 0, 0.7%) at 12 mo with no difference between delivery mode. When present, average pain intensity was mild (Table 1). Among those with positive neuropathic pain score, average scoreSEM was 12 4 (Ranges: 2 - 43). In investigating SOL, data from 24 pts with 12 from each gp were analyzed. Spinal oxytocin conc. SEM were 27.83.7 & 31.5 3.5 pg/mL for non-peripartum gynecological and PP gp, respectively with no statistical difference.

Discussions: We found a low incidence of CPAD at 6 & 12 months, unaffected by mode of delivery. Contrary to our hypothesis, SOL was not different between immediate PP & non-peripartum pts. Even though protection of hypersensitivit

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