Relief of pain caused by uterine cramping or involution after giving birth

This updated review investigates the effectiveness and safety of drug and non-drug pain relief in women experiencing after-birth pains following vaginal birth. Giving an agent for pain relief was compared to an inactive placebo, to no treatment, or to a different type of agent in randomised controlled trials.

What is the issue?

Women may experience cramping pain and discomfort following the birth of their baby, as the uterus contracts and returns to its normal pre-pregnancy size. These pains usually last for two to three days after the birth. Women who have previously had a baby are more likely to experience after-birth pains. Breastfeeding stimulates the uterus to contract and increases the severity of the pains.

Types of pain relief used to treat the pain include paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen and naproxen, opioids including codeine, and non-medicine methods such as herbal preparations and transcutaneous electrical nerve stimulation (TENS).

Why is this important?

Management of pain after birth is important, as the pain can affect a mother carrying out her normal activities as well as bonding with and caring for her baby. After-pains can interfere with establishing breastfeeding.

What evidence did we find?

We searched for evidence from randomised controlled trials (October 2019) and identified 28 studies (2749 mothers) who were in hospital after uncomplicated single births. Most of the evidence is low-certainty because the studies did not include sufficient numbers of women. Many of the studies excluded breastfeeding women.This makes the evidence less relevant to a broader group of women. No studies reported evidence on adverse events in the newborn infants.

NSAIDs are probably better than placebo (a dummy treatment) in giving adequate pain relief as reported by the women (11 studies, 946 women; moderate-certainty evidence), and they may reduce the need for additional pain relief (4 studies, 375 women; low-certainty evidence). There may be little difference between NSAIDs and placebo in the risk of adverse events in the mother (9 studies, 598 women; low-certainty evidence).

NSAIDs are probably better than opioids in providing adequate pain relief as reported by the women (5 studies, 560 women; moderate-certainty evidence) and may reduce the risk of adverse events in the mother (3 studies, 255 women; low-certainty evidence). NSAIDs may slightly reduce the need for additional pain relief compared with opioids (2 studies, 232 women; low-certainty evidence).

Opioids may be better than placebo for adequate pain relief as reported by the women (5 studies, 299 women; low-certainty evidence) and for the need for additional pain relief (3 studies, 273 women; low-certainty evidence). Opioids may increase the risk of adverse events in the mother compared with placebo (3 studies, 188 women; low-certainty evidence).

Very low-certainty evidence means we are uncertain if paracetamol is better than placebo for adequate pain relief as reported by the women, the need for additional analgesia, or risk of maternal adverse events (2 studies, 123 women).

Very low-certainty evidence means we are uncertain if there are any differences between paracetamol and NSAIDs for adequate pain relief as reported by the women, or the risk of maternal adverse events (2 studies, 112 women).

Very low-certainty evidence means we are uncertain if NSAIDs are better than herbal pain relief for adequate pain relief as reported by the women (4 studies, 394 women), the need for additional pain relief (1 study, 90 women) or risk of maternal adverse events (1 study, 108 women).

Very low-certainty evidence means we are uncertain if there is any difference between TENS and no TENS for adequate pain relief as reported by the women (1 study, 32 women).

What does this mean?

NSAIDs may be better than placebo and are probably better than opioids at relieving after-birth pains following vaginal birth. The quality of the evidence was poor and we are uncertain about the effectiveness of other forms of pain relief. Future trials should recruit adequate numbers of women and ensure greater relevance by including breastfeeding women. Further research could also include a survey of women after delivery to capture their experience of after-birth pains following vaginal birth.

Authors' conclusions: 

NSAIDs may be better than placebo and are probably better than opioids at relieving pain from uterine cramping/involution following vaginal birth. NSAIDs and paracetamol may be as effective as each other, whereas opioids may be more effective than placebo. Due to low-certainty evidence, we are uncertain about the effectiveness of other forms of pain relief. Future trials should recruit adequate numbers of women and ensure greater generalisability by including breastfeeding women. In addition, further research is required, including a survey of postpartum women to describe appropriately their experience of uterine cramping and involution. We identified nine ongoing studies, which may help to increase the level of certainty of the evidence around pain relief due to uterine cramping in future updates of this review.

Read the full abstract...
Background: 

Women may experience differing types of pain and discomfort following birth, including cramping pain (often called after-birth pain) associated with uterine involution, where the uterus contracts to reduce blood loss and return the uterus to its non-pregnant size. This is an update of a review first published in 2011.

Objectives: 

To assess the effectiveness and safety of pharmacological and non-pharmacological pain relief/analgesia for the relief of after-birth pains following vaginal birth.

Search strategy: 

For this update, we searched Cochrane Pregnancy and Childbirth’s Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (31 October 2019), and reference lists of retrieved studies.

Selection criteria: 

Randomised controlled trials comparing two different types of analgesia or analgesia versus placebo or analgesia versus no treatment, for the relief of after-birth pains following vaginal birth. Types of analgesia included pharmacological and non-pharmacological. Quasi-randomised trials were not eligible for inclusion.

Data collection and analysis: 

Two review authors independently assessed trials for inclusion, conducted 'Risk of bias' assessment, extracted data and assessed the certainty of the evidence using the GRADE approach.

Main results: 

In this update, we include 28 studies (involving 2749 women). The evidence identified in this review comes from middle- to high-income countries. Generally the trials were at low risk of selection bias, performance bias and attrition bias, but some trials were at high risk of bias due to selective reporting and lack of blinding. Our GRADE certainty of evidence assessments ranged from moderate to very low certainty, with downgrading decisions based on study limitations, imprecision, and (for one comparison) indirectness.

Most studies reported our primary outcome of adequate pain relief as reported by the women. No studies reported data relating to neonatal adverse events, duration of hospital stay, or breastfeeding rates. Almost half of the included studies (11/28) excluded breastfeeding women from participating, making the evidence less generalisable to a broader group of women.

Non-steroidal anti-inflammatory drugs (NSAIDs) compared to placebo

NSAIDs are probably better than placebo for adequate pain relief as reported by the women (risk ratio (RR) 1.66, 95% confidence interval (CI) 1.45 to 1.91; 11 studies, 946 women; moderate-certainty evidence). NSAIDs may reduce the need for additional pain relief compared to placebo (RR 0.15, 95% CI 0.07 to 0.33; 4 studies, 375 women; low-certainty evidence). There may be a similar risk of maternal adverse events (RR 1.05, 95% CI 0.78 to 1.41; 9 studies, 598 women; low-certainty evidence).

NSAIDs compared to opioids

NSAIDs are probably better than opioids for adequate pain relief as reported by the women (RR 1.33, 95% CI 1.13 to 1.57; 5 studies, 560 women; moderate-certainty evidence) and may reduce the risk of maternal adverse events (RR 0.62, 95% CI 0.43 to 0.89; 3 studies, 255 women; low-certainty evidence). NSAIDs may be better than opioids for the need for additional pain relief, but the wide CIs include the possibility that the two classes of drugs are similarly effective or that opioids are better (RR 0.37, 95% CI 0.12 to 1.12; 2 studies, 232 women; low-certainty evidence).

Opioids compared to placebo

Opioids may be better than placebo for adequate pain relief as reported by the women (RR 1.26, 95% CI 0.99 to 1.61; 5 studies, 299 women; low-certainty evidence). Opioids may reduce the need for additional pain relief compared to placebo (RR 0.48, 95% CI 0.28 to 0.82; 3 studies, 273 women; low-certainty evidence). Opioids may increase the risk of maternal adverse events compared with placebo, although the certainty of evidence is low (RR 1.59, 95% CI 0.99 to 2.55; 3 studies, 188 women; low-certainty evidence).

Paracetamol compared to placebo

Very low-certainty evidence means we are uncertain if paracetamol is better than placebo for adequate pain relief as reported by the women, the need for additional pain relief, or risk of maternal adverse events (2 studies, 123 women).

Paracetamol compared to NSAIDs

Very low-certainty evidence means we are uncertain if there are any differences between paracetamol and NSAIDs for adequate pain relief as reported by the women, or the risk of maternal adverse events. No data were reported about the need for additional pain relief comparing paracetamol and NSAIDs (2 studies, 112 women).

NSAIDs compared to herbal analgesia

We are uncertain if there are any differences between NSAIDs and herbal analgesia for adequate pain relief as reported by the women, the need for additional pain relief, or risk of maternal adverse events, because the certainty of evidence is very low (4 studies, 394 women).

Transcutaneous nerve stimulation (TENS) compared to no TENS

Very low-certainty evidence means we are uncertain if TENS is better than no TENS for adequate pain relief as reported by the women. No other data were reported comparing TENS with no TENS (1 study, 32 women).

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