Interventions for preventing constipation after giving birth

What is the issue?

Constipation during the postpartum period is a bowel disorder, characterised by symptoms, such as pain or discomfort, straining, hard lumpy stool, and a sense of incomplete bowel evacuation. 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. This is an update of a review first published in 2015.

Why is this important?

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 because of undue pressure on the rectal wall, leading to restlessness and painful defecation, which may affect the quality of life of the mother and the newborn.

What evidence did we find?

We searched for trials to 7 October 2019. We found no new trials that met our inclusion criteria, thus, we included the initial five trials (involving a total of 1208 women) in this update. Overall, the trials were poorly reported, and four out of five trials were published more than 40 years ago. Four trials compared a laxative with a placebo.

Two trials assessed the effects of laxatives that we now find might be harmful for breastfeeding mothers. One drug, Danthron, has been shown to cause cancer in animals, and the other, Bisoxatin acetate, is no longer recommended when breastfeeding. Therefore, we did not include the results of these trials in our main findings.

The trials did not look at pain or straining on defecation, incidence of constipation, or quality of life, but did assess the time to first bowel movement. In one study assessing the effects of senna, compared to the placebo group, more women in the laxative group had a bowel movement on the day of delivery, and fewer women had their first bowel movement on days 2 and 3, while the results were inconclusive between groups on days 1 and 4 after delivery. More women had abdominal cramps compared to the women in the placebo group, and babies whose mothers received the laxative were no more likely to experience loose stool or diarrhoea. The evidence for all these outcomes is largely uncertain, as we have very serious concerns about risk of bias, and the results are all based on one small study that was conducted at a single institution in South Africa.

One trial compared a laxative plus a stool-bulking agent (Ispaghula husk) to a laxative only for women who underwent surgery to repair a third degree tear of the perineum (involving the internal or external anal sphincter muscles) that occurred during vaginal delivery. The trial reported on pain or straining on defecation, but did not find a clear difference in the pain score between groups. The trial reported that women who were given laxative plus a stool-bulking agent were more likely to experience fecal incontinence in the immediate postpartum period. However, the evidence is very uncertain. The trial did not report on any adverse effects on the baby.

What does this mean?

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 need large, high-quality trials on this topic, specifically on non-medical interventions to prevent postpartum constipation, such as advice on diet and physical activity.

Authors' conclusions: 

There is insufficient evidence to make general conclusions about the effectiveness and safety of laxatives for preventing postpartum constipation. The evidence in this review was assessed as low to very low-certainty evidence, with downgrading decisions based on limitations in study design, indirectness and imprecision.

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.

Further, rigorous trials are needed to assess the effectiveness and safety of laxatives during the postpartum period for preventing constipation. Trials should assess educational and behavioural interventions, and positions that enhance defecation. They should report on the primary outcomes from this review: 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.

Read the full abstract...
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 are usually encouraged. Although laxatives are commonly used in relieving constipation, the effectiveness and safety of available interventions for preventing postpartum constipation should be ascertained. This is an update of a review first published in 2015.

Objectives: 

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

Search strategy: 

We searched Cochrane Pregnancy and Childbirth’s Trials Register, and two trials registers ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (7 October 2019), and screened reference lists of retrieved trials.

Selection criteria: 

We considered all randomised controlled trials (RCTs) comparing any intervention for preventing postpartum constipation versus another intervention, placebo, or no intervention in postpartum women. Interventions could include pharmacological (e.g. laxatives) and non-pharmacological interventions (e.g. acupuncture, educational and behavioural interventions). Quasi-randomised trials and cluster-RCTs were eligible for inclusion; none were identified. Trials using a cross-over design were not eligible.

Data collection and analysis: 

Two review authors independently screened the results of the search to select potentially relevant trials, extracted data, assessed risk of bias, and the certainty of the evidence, using the GRADE approach. We did not pool results in a meta-analysis, but reported them per study.

Main results: 

We included five trials (1208 postpartum mothers); three RCTs and two quasi-RCTs. Four trials compared a laxative with placebo; one compared a laxative plus a bulking agent versus the same laxative alone, in women who underwent surgical repair of third degree perineal tears. Trials were poorly reported, and four of the five trials were published over 40 years ago. We judged the risk of bias to be unclear for most domains. Overall, we found a high risk of selection and attrition bias.

Laxative versus placebo

We included four trials in this comparison. Two of the trials examined the effects of laxatives that are no longer used; one has been found to have carcinogenic properties (Danthron), and the other is not recommended for lactating women (Bisoxatin acetate); therefore, we did not include their results in our main findings.

None of the trials included in this comparison assessed our primary outcomes: pain or straining on defecation, incidence of postpartum constipation, or quality of life; or many of our secondary outcomes.

A laxative (senna) may increase the number of women having their first bowel movement within 24 hours after delivery (risk ratio (RR) 2.90, 95% confidence interval (CI) 2.24 to 3.75; 1 trial, 471 women; low-certainty evidence); may have little or no effect on the number of women having their first bowel movement on day one after delivery (RR 0.94, 95% CI 0.72 to 1.22; 1 trial, 471 women; very low-certainty evidence); may reduce the number of women having their first bowel movement on day two (RR 0.23, 95% CI 0.11 to 0.45; 1 trial, 471 women; low-certainty evidence); and day three (RR 0.05, 95% CI 0.00 to 0.89; 1 trial, 471 women; low-certainty evidence); and may have little or no effect on the number of women having their first bowel movement on day four after delivery (RR 0.22, 95% CI 0.03 to 1.87; 1 trial, 471 women; very low-certainty evidence), but some of the evidence is very uncertain.

Adverse effects were poorly reported. Low-certainty evidence suggests that the laxative (senna) may increase the number of women experiencing abdominal cramps (RR 4.23, 95% CI 1.75 to 10.19; 1 trial, 471 women). Very low-certainty evidence suggests that laxatives taken by the mother may have little or no effect on loose stools in the baby (RR 0.62, 95% CI 0.16 to 2.41; 1 trial, 281 babies); or diarrhoea (RR 2.46, 95% CI 0.23 to 26.82; 1 trial, 281 babies).

Laxative plus bulking agent versus laxative only

Very low-certainty evidence from one trial (147 women) suggests no evidence of a difference between these two groups of women who underwent surgical repair of third degree perineal tears; only median and range data were reported. The trial also reported no evidence of a difference in the incidence of postpartum constipation (data not reported), but did not report on quality of life. Time to first bowel movement was reported as a median (range); very low-certainty evidence suggests little or no difference between the two groups. A laxative plus bulking agent may increase the number of women having any episode of faecal incontinence during the first 10 days postpartum (RR 1.81, 95% CI 1.01 to 3.23; 1 trial, 147 women; very low-certainty evidence). The trial did not report on adverse effects of the intervention on babies, or many of our secondary outcomes.

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