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 METHODS: 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.
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.