Analgesia for relief of pain due to uterine cramping/involution after birth.

BACKGROUND: Women may experience differing types of pain and discomfort following birth, including cramping after birth pains associated with uterine involution.

OBJECTIVES: To assess the effectiveness and safety of analgesia for relief of after birth pains following vaginal birth.

SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2010) and the reference lists of trials and review articles.

SELECTION CRITERIA: All identified published and unpublished randomised controlled trials comparing two different types of analgesia or analgesia with placebo or analgesia with no treatment, for the relief of after birth pains following vaginal birth. Types of analgesia included pharmacological and non-pharmacological.

DATA COLLECTION AND ANALYSIS: Two review authors assessed trial quality and extracted data independently.

MAIN RESULTS: We have included 18 studies (involving 1498 women) in this review. However, only nine of the included studies (with 750 women) reported 24 comparisons of analgesia with other analgesia or placebo and had data that could be included in our meta-analyses. The majority of studies investigated pharmacological analgesics and these were grouped into classes for this review. Non-steroidal anti-inflammatory drugs (NSAIDs) were significantly better than placebo at relieving pain from uterine involution as assessed by their summed pain intensity differences (SPID) (mean difference (MD) 4.34; 95% confidence interval (CI) 2.87 to 5.82; three studies, 204 women) and summed pain relief scores (MD 5.94; 95% CI 3.83 to 8.01; three studies, 204 women). NSAIDS were compared with opioids in one small study of 23 women reporting SPID and summed pain relief and found no difference. A larger study of 127 women found NSAIDs to be significantly better than opioids at reducing pain intensity six hours following study intervention (MD -0.70; 95% CI -1.04 to -0.35). Opioids were compared with placebo in three studies that could be included in meta-analyses; one small study of 23 women reporting SPID and summed pain relief and found no difference. One study of 95 women found no difference in pain intensity six hours following the study intervention. A third study of 108 women found significantly more women in the placebo group reported no pain relief than women in the opioid group (risk ratio 0.10; 95% CI 0.04 to 0.23). Aspirin was significantly better than paracetamol when pain intensity score was assessed six hours after study intervention (MD 0.85; 95% CI 0.29 to 1.41; one study 48 women) at relieving pain from uterine involution. Paracetamol was not better than placebo when pain intensity was assessed six hours after the study intervention in one study of 48 women.

AUTHORS' CONCLUSIONS: Non-steroidal anti-inflammatory drugs (NSAID) including aspirin were better than placebo at relieving pain from uterine cramping/involution following vaginal birth. NSAIDs were better than paracetamol and paracetamol was not better than placebo, though numbers of participants for these comparisons were small. Data for opioids compared with NSAIDs and opioids compared with placebo were conflicting, with some measures showing similar effect and others indicating NSAIDs were better than opioids and opioids were not better than placebo. There were insufficient data to make conclusions regarding the effectiveness of opioids at relieving pain from uterine cramping/involution.The median year of publication of included studies was 1981; therefore more research is needed to assess the effectiveness of current pharmacological and non-pharmacological analgesia at relieving pain from uterine cramping/involution following vaginal birth.