The effect of fixed-time interval and on-demand analgesia protocols for post cesarean pain on maternal chronic pain and child development - follow up of randomized controlled trial.

Objective: Post-cesarean delivery (CD) acute pain may progress to chronic pain, which may impair maternal bonding and child development. In 2013, we compared the efficacy of versus on-demand oral analgesia for post-caesarean pain in a randomized-controlled-trial. The fixed-time-interval group had received scheduled paracetamol, tramadol, and diclofenac regardless of pain level, and the on-demand group received medication as needed, with oxycodone reserved for unrelieved pain in both groups. We found that The 'fixed-time-interval' group had lower pain scores, higher satisfaction rate and more breastfeeds. We aimed to assess the long-term effects of the study protocols on maternal chronic pain and child development.

Study Design: During September 2022 to January 2023, women who participated in the original study were approached by phone. The Brief Pain Inventory (BPI) was used to assess the presence and severity of mother's chronic pain and the impact on their functioning as was used in previous studies that assessed post-cesarean chronic pain. The child behavior checklist (CBCL) was filled by the mother and used to characterize child emotional and behavioral problems. CBCL assesses internalizing behaviors, externalizing behaviors, and total problems. T-scores>63 are considered clinically significant (pathologic range). The interviewer was blinded to the original group. The primary endpoints were chronic pain involving the CD scar area and rate of children within the pathologic range of each CBCL category. Background data was obtained via both parent report and medical records review. The incidence of chronic pain following CD ranges between 4-42%. In the general population, around 5% of children are within the CBCL pathologic range. We assumed that the rate of maternal chronic pain involving the CD scar area as well as the rate of pathologic range of CBCL internalization, externalization, or overall domains would be 5% versus 30% in the fixed-time-interval and on-demand groups, respectively. Thus, the sample size required was 86 women (2.5% two-sided alpha, 80% power). The study was approved by the institutional review board (EMC-167-21).

Results: Of the 200 participants of the original study, 92 (46%) consented to participate in the follow-up study. Of them, 45 were originally from the on-demand and 47 from the fixed-time-interval groups. There were 7 couples of twins overall, therefore 49 children in the on-demand group and 50 children in the fixed-time-interval group. When comparing the background characteristics of the women who answered the questionnaires, to those who did not, the only difference was the ethnicity. For Jewish women, 59 (64%) took part in the current study, as opposed to 50 (46%) who did not. As for Arab women, 33 (36%) participated in the current study, and 58 (54%) did not (P = 0.01). Mothers and neonates' background characteristics were not different between the groups (table 1). The BPI results are presented in table 2. More women in the on-demand group reported on chronic pain involving the CD scar area compared to the fixed-time-interval group (15 [33%] vs 3 [6%] respectively; P=0.001). Regarding the characteristics of chronic pain, there were no distinct differences between the two groups for most of the pain features (table 2). Pain ratings in both groups were in the mild range. Women from the fixed-time-interval group had rated the relationship with other people interference higher than those at the on-demand group (P=0.01). Due to the small number of women who reported pain in the CD scar area, we could not perform sub-analysis for this item in those women. The rest of the features were not different between the groups. In sub-analysis of women who reported on chronic pain involving the CD scar area there was no difference in any of the features (data not shown). The CBCL results are presented in table 2. Pathologic externalization behavior was more prevalent in children born to mothers in the on-demand group compared with the fixed-time-interval group (9 [18%] vs 2 [4%] respectively; P=0.02). Other features tested, were not statistically significant between the groups. Pain in the scar area was associated with pathological externalization behavior (5/19 [26%] vs 6/80 [8%] in woman with and without pain, respectively; P=0.03). Comparison of the maternal and children characteristics (described in table 1) between women with and without chronic pain showed no differences (data not shown). Externalization score was not correlated with the number of breastfeedings during post CD hospitalization (Spearman's correlation coefficient -0.06, P=0.53).

Conclusions: Appropriate post-cesarean acute pain management may be an important factor to prevent maternal chronic pain and consequently abnormal child development. Further studies are needed that account for potential confounding variables and consider the extended time interval since childbirth.