Insufficient evidence for most effective analgesics following vaginal birth

Clinical question: 
Which are the most effective analgesics for pain relief from uterine cramping/involution following vaginal birth?
Bottom line: 
Non-steroidal anti-inflammatory drugs (NSAIDs) including aspirin were better than placebo in relieving pain 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 was insufficient evidence to make any recommendations for clinical practice.
Caveat: 
Only 9 of the included studies (with 750 women) reporting 24 comparisons of analgesia with other analgesia or placebo had data that could be included in the meta-analyses. The majority of analyses in this review included only 1 study with small numbers of participants. The average year of the included studies was 1981.
Context: 
Women may experience cramping pain and discomfort following the birth of their baby as the uterus contracts and returns to its pre-pregnancy size. These after-birth pains are caused by involutionary contractions and usually last for 2 to 3 days after childbirth. They are more evident for women who have previously had a baby. Breastfeeding stimulates the uterus to contract and increases the severity of after-birth pains.
Review CD#: 
CD004908
PEARLS No: 
324
Date: 
August, 2011
Authored by: 
Brian R McAvoy