Interventions for preventing constipation after giving birth

Constipation is a bowel disorder that is characterised by symptoms such as pain or discomfort, straining, hard lumpy stool and a sense of incomplete bowel evacuation. Pain and discomfort during defecation can be a source of concern to the new mother who is recuperating from the stress of delivery, particularly if she has had perineal tears repaired or has developed haemorrhoids. Postpartum constipation can be stressful for women because of undue pressure on the rectal wall, leading to restlessness and painful bowel movements which may affect the quality of life of the mother. The administration of enemas before labour, the ability of women to eat during active labour, and irregular and altered eating habits during the first few days after delivery can each have an influence on bowel movements in the days after giving birth. We aimed to find all the trials assessing interventions that could prevent postpartum constipation. We examined the available evidence up to 30 April 2015. We included five randomised controlled trials (involving a total of 1208 women from the first day of giving birth) in this review. Overall, the trials were poorly conducted and reported.

Four trials compared a laxative with a placebo control. The trials did not look at pain or straining on defecation, incidence of constipation, or changes in the quality of life, but did assess the time to first bowel movement. More women in the laxative group had a bowel movement on the day of delivery in one trial. For days one, two and three after the birth, the findings from the trials were not consistent. Combined results of two trials found that more women in the placebo group had their first bowel movement bowel four days after delivery compared to the laxative group. Adverse effects of the intervention were poorly reported in the trials. Two trials reported on abdominal cramps but we were unable to combine the results of the two trials because they were very different (one study found more women had abdominal cramps compared to the women in the placebo control group whereas the other study found no difference between groups). In terms of adverse effects of the intervention for the baby, one trial found that babies whose mothers received laxative were no more likely to experience loose stool or diarrhoea.

One trial compared a laxative with a laxative plus a stool-bulking agent (Ispaghula husk) for women who underwent surgery to repair a tear of the perineum involving the internal or external anal sphincter muscles (third degree) that occurred during vaginal delivery. The trial reported on pain or straining on defecation but did not find a difference in the pain score between groups. In terms of adverse effects of the intervention, the trial reported that women who were given laxative plus a stool-bulking agent were more likely to experience fecal incontinence during the immediate postpartum period. However the number of women having any episode of faecal incontinence during first 10 days postpartum was reported with no clear difference between the laxative and the laxative plus stool-bulking agent group (14/77 (18.2%) versus 23/70 (32.9%), 147 women). This trial reported no data in relation to any adverse effects that the intervention might have on the baby.

There is not enough evidence from randomised controlled trials on the effectiveness and safety of laxatives during the early postpartum period to make general conclusions about their use to prevent constipation. We did not identify any trials assessing educational or behavioural interventions such as a high-fibre diet and exercise.

We found some evidence that adding a stool-bulking agent to a laxative for women who underwent surgery to repair a third degree perineal tear is not beneficial. Large, high-quality trials are needed on this topic. In addition, trials looking at non-medical interventions, such as advice on diet and physical activity, are needed.

Authors' conclusions: 

We did not identify any trials assessing educational or behavioural interventions. We identified four trials that examined laxatives versus placebo and one that examined laxatives versus laxatives plus stool bulking agents. Results from trials were inconsistent and there is insufficient evidence to make general conclusions about the effectiveness and safety of laxatives.

Further rigorous trials are needed to assess the effectiveness and safety of laxatives during the postpartum period for preventing constipation. Trials assessing educational and behavioural interventions and positions that enhance defecation are also needed. Future trials should report on the following important outcomes: pain or straining on defecation; incidence of postpartum constipation, quality of life, time to first bowel movement after delivery, and adverse effects caused by the intervention such as: nausea or vomiting, pain and flatus.

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Background: 

Postpartum constipation, with symptoms such as pain or discomfort, straining, and hard stool, is a common condition affecting mothers. Haemorrhoids, pain at the episiotomy site, effects of pregnancy hormones and haematinics used in pregnancy can increase the risk of postpartum constipation. Eating a high-fibre diet and increasing fluid intake is usually encouraged, although laxatives are commonly used in relieving constipation. The effectiveness and safety of available interventions for preventing postpartum constipation needs to be ascertained.

Objectives: 

To evaluate the effectiveness and safety of interventions for preventing postpartum constipation.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2015), Stellenbosch University database, ProQuest Dissertation and Theses database, World Health Organization International Clinical Trials Registry Platform (ICTRP), ClinicalTrials.gov (30 April 2015) and reference lists of included studies.

Selection criteria: 

All randomised controlled trials (RCTs) comparing any intervention for preventing postpartum constipation versus another intervention, placebo or no intervention. Interventions could include pharmacological (e.g. laxatives) and non-pharmacological interventions (e.g. acupuncture, educational and behavioural interventions).

We included quasi-randomised trials. Cluster-RCTs were eligible for inclusion but none were identified. Studies using a cross-over design were not eligible for inclusion in this review.

Data collection and analysis: 

Two review authors independently screened the results of the search to select potentially relevant studies, extracted data and assessed risk of bias. Results were pooled in a meta-analysis only where there was no substantial statistical heterogeneity.

Main results: 

We included five trials (1208 postpartum mothers); four compared a laxative with placebo and one compared a laxative alone versus the same laxative plus a bulking agent in women who underwent surgical repair of third degree perineal tears. Trials were poorly reported and risk of bias was unclear for most domains. Overall, there was a high risk of selection and attrition bias.

Laxative versus placebo

None of the four trials included in this comparison assessed any of our pre-specified primary outcomes ( pain or straining on defecation, incidence of postpartum constipation or changes in quality of life).

All four trials reported time to first bowel movement (not pre-specified in our protocol). In one trial, more women in the laxative group had their first bowel movement less than 24 hours after delivery compared to women in the placebo group (risk ratio (RR) 2.90, 95% confidence interval (CI) 2.24 to 3.75, 471 women). Individual trials also reported inconsistent results for days one, two and three after delivery. Pooled results of two trials showed that fewer women in the laxative group were having their first bowel movement at day four compared with controls (average RR 0.36, 95% CI 0.21 to 0.61, 671 women).

Regarding secondary outcomes, no trials reported on stool consistency using the Bristol stool form scale or relief of abdominal pain/discomfort . One trial reported the number of women having loose or watery stools and there were more women who experienced this in the laxative group compared to the placebo group (RR 26.96, 95% CI 3.81 to 191.03, 106 women). One trial found no clear difference in the number of enemas between groups (RR 0.63, 95% CI 0.38 to 1.05, 244 women). One trial reported more women having more than two bowel movements per day in the laxative compared to the placebo group (RR 26.02, 95% CI 1.59 to 426.73, 106 women).

Adverse effects were poorly reported; two trials reported the number of women having abdominal cramps, but their results could not be pooled in a meta-analysis due to substantial statistical heterogeneity. In one trial, more women in the laxative group had abdominal cramps compared to the placebo group (RR 4.23, 95% CI 1.75 to 10.19, 471 women), while the other trial showed no difference between groups (RR 0.25, 95% CI 0.03 to 2.20, 200 women). With regards to adverse effects of the intervention on the baby , one trial found no difference in the incidence of loose stools (RR 0.62, 95% CI 0.16 to 2.41, 281 women) or diarrhoea (RR 2.46, 95% CI 0.23 to 26.82, 281 women) between the two groups.

Laxative versus laxative plus bulking agent

Only one trial was included in this comparison and reported on pain or straining on defecation in women who underwent surgical repair of third degree perineal tears; there was no reported difference between groups (median (range) data only). No difference was reported in the incidence of postpartum constipation (data not reported) and the outcome changes in quality of life was not mentioned. Time to first bowel movement was reported as a median (range) with no difference between the two groups. In terms of adverse effects , women in the laxative plus stool-bulking group were reported to be at a greater risk of faecal incontinence during the immediate postpartum period (median (range) data only). However the number of women having any episode of faecal incontinence during first 10 days postpartum was reported with no clear difference between the two groups (14/77 (18.2%) versus 23/70 (32.9%), RR 0.55, 95% CI 0.31 to 0.99, 147 women). The trial did not report on adverse effects of the intervention on the babies.

The trial reported none of the following pre-specified secondary outcomes: stool consistency using Bristol stool form scale , use of alternative products , laxative agents , enemas , relief of abdominal pain/discomfort and stool frequency .

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