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Am Fam Physician. 2021;104(6):575-577

This clinical content conforms to AAFP criteria for CME.

Author disclosure: No relevant financial affiliations.

Clinical Question

Is a single dose of an oral nonsteroidal anti-inflammatory drug (NSAID) or acetaminophen effective for acute perineal pain in the early post-partum period?

Evidence-Based Answer

In patients with acute perineal pain at four hours' postpartum, a single dose of an oral NSAID (number needed to treat [NNT] = 4; 95% CI, 3 to 6)1 and a single dose of oral acetaminophen (NNT = 3; 95% CI, 2 to 6)2 are each effective at achieving adequate pain relief. Both NSAIDs (NNT = 5; 95% CI, 4 to 8) and acetaminophen (NNT = 5; 95% CI, 4 to 7) are effective at reducing the need for further analgesia. It is unclear whether an NSAID or acetaminophen is superior. It should be noted that these data are based on studies in which a majority of patients underwent episiotomy.1,2 (Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.)

OutcomesAssumed risk with placebo or acetaminophenCorresponding risk with medication (95% CI)NNT* (95% CI)ParticipantsQuality of evidence
Adequate pain relief (4 hours)PlaceboNSAID
284 per 1,000543 per 1,000 (466 to 634 per 1,000)4 (3 to 6)1,573Low
205 per 1,000315 per 1,000 (219 to 454 per 1,000)9 (4 to 71)342Low
27%58% (43% to 78%)3 (2 to 6)1,279Low
Adequate pain relief (6 hours)PlaceboNSAID
321 per 1,000615 per 1,000 (542 to 696 per 1,000)3 (3 to 5)2,079Very low
200 per 1,000364 per 1,000 (122 to 1,000 per 1,000)NA99Very low
Need for additional analgesia (4 hours)PlaceboNSAID
305 per 1,000119 per 1,000 (79 to 177 per 1,000)5 (4 to 8)486Moderate
405 per 1,000223 per 1,000 (109 to 458 per 1,000)NA73Very low
30.5%10.4% (6.4% to 16.8%)5 (4 to 7)1,132Low
Need for additional analgesia (6 hours)PlaceboNSAID
438 per 1,000140 per 1,000 (114 to 175 per 1,000)3 (3 to 4)1,012Very low
571 per 1,000160 per 1,000 (69 to 383 per 1,000)2 (2 to 5)59Low

Practice Pointers

Perineal pain is common following vaginal delivery. Achieving adequate pain relief is important to improve patients' well-being, mobility, and ability to care for their child. NSAIDs and acetaminophen are commonly used postpartum for analgesia. The authors of these two Cochrane reviews sought to demonstrate whether a single dose of an NSAID or acetaminophen can significantly reduce early postpartum perineal pain.1,2

The first Cochrane review evaluated the effectiveness of NSAIDs from 35 randomized controlled trials (RCTs; N = 5,136) that examined 16 different NSAIDs.1 Sixteen of the 35 studies took place in the United States and eight in other high-income countries (Canada, United Kingdom, Belgium, Spain, France, and Italy). Eleven studies were done in low- and middle-income countries—six in Venezuela, and five in India, Malaysia, Thailand, and Iran. Participants had perineal trauma requiring repair following vaginal delivery. Nearly all of the studies (34 of 35) evaluated postepisiotomy pain, and one study evaluated patients with first- or second-degree perineal tears. Episiotomies are not routinely recommended, which is a major limitation of this review. The studies assessed a single dose of medication vs. a single dose of placebo, acetaminophen, or another NSAID. Outcomes included achieving adequate pain relief and the need for additional analgesia. Adequate pain relief was defined as patients subjectively reporting “good” or “excellent” pain relief or pain relief of 50% or greater four to six hours following treatment. The review did not specify parity or gravidity.

Patients who received a single dose of an NSAID achieved adequate pain relief at four hours (NNT = 4; 95% CI, 3 to 6) and at six hours (NNT = 3; 95% CI, 3 to 5) compared with placebo. Patients who received an NSAID were less likely to need additional analgesia at four hours (NNT = 5; 95% CI, 4 to 8) and at six hours (NNT = 3; 95% CI, 3 to 4) compared with placebo. Limitations included risk of sampling bias, undisclosed details regarding randomization and blinding, and imprecision resulting in wide CIs, largely due to small sample sizes and few events. The data on adequate pain relief were asymmetrical, especially compared with the data evaluating the need for additional analgesia. This suggests that additional smaller studies of NSAIDs vs. placebo have likely not been published, and thus there may be an overestimation of the effect of NSAIDs.

A Cochrane meta-analysis demonstrated that NSAIDs are superior to acetaminophen at helping to achieve adequate pain relief at four hours (NNT = 9; 95% CI, 4 to 71), but there was no statistically significant difference in this outcome at six hours. The need for additional analgesia at six hours was reduced with NSAIDs compared with acetaminophen (NNT = 2; 95% CI, 2 to 5), but not at four hours. Thus, there is no clear difference in effectiveness of NSAIDs compared with acetaminophen. Further comparisons between different NSAIDs or different doses of an NSAID did not demonstrate any statistical difference in outcomes. Assessment of maternal adverse drug effects was uncertain, and neonatal adverse drug effects were not reported. Quality of evidence in the individual studies was low to very low because of unclear risk of selection bias, few participants, and wide CIs that suggest possible benefit and possible harm.

The second Cochrane review included 10 RCTs (N = 1,301) assessing a single dose of acetaminophen vs. placebo in providing perineal pain relief.2 The settings of the trials were hospitals in mostly high-income countries—seven in the United States, one in France, one in Canada, and one in Venezuela (the only low- to middle-income country). All of the studies were small; the largest included only 250 patients. The studies involved only patients with perineal pain associated with trauma, and none of the participants had an intact perineum. The studies assessed 500- to 1,000-mg doses of acetaminophen. More patients experienced adequate pain relief with acetaminophen at four hours after birth (NNT = 3; 95% CI, 2 to 6) compared with placebo, and fewer patients needed additional analgesia with acetaminophen compared with placebo (NNT = 5; 95% CI, 4 to 7). Only one of the included studies reported maternal adverse drug effects; neonatal adverse drug effects were not assessed.

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