Constipation in pregnancyTina Sara Verghese MBBS,a,* Kaori Futaba FRCS MMedSci,b Pallavi Latthe MD MRCOGc

aClinical Research Fellow, Obstetrics and Gynaecology, BirminghamWomens NHS Foundation Trust, Edgbaston, Birmingham, West Midlands B15

2TG, UKbConsultant Colorectal Surgeon, Department of Colorectal Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS

Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham B15 2GW, UKcConsultant Obstetrician and Gynaecologist, Subspecialist in Urogynaecology, Department of Obstetrics & Gynaecology, Birmingham Womens

NHS Foundation Trust, Edgbaston, Birmingham, West Midlands B15 2TG, UK

*Correspondence: Tina Verghese. Email: t.s.verghese@bham.ac.uk

Accepted on 28 January 2015

Key content Constipation affects up to 38% of pregnancies. Rising progesterone levels in pregnancy contribute to slowgut motility.

The standard clinical measures of chronic constipation are theRome III criteria, which are based on frequency and difficulty in

the passage of stool. Secondary constipation is due to primary disease of the colon (analfissure, stricture and neoplasia), metabolic disturbances

(hypothyroidism and hypercalcaemia) and neurological disorders. Severe constipation may result in faecal impaction, retention ofurine, pain or abdominal discomfort, rectal bleeding and/or

rectal prolapse. A treatment algorithm using laxatives that are effective, safe andnon-teratogenic will be discussed.

Learning objectives To understand the prevalence and pathophysiology of thiscondition in pregnancy.

To understand the management of constipation in pregnancy.

Ethical issues The studies on safety of laxatives in pregnancy have small samplesizes although they have not shown any effect on

congenital malformations. When to involve a gastroenterologist or a colorectal surgeon in thecare of a woman with constipation in pregnancy.

Keywords: constipation / laxatives

Please cite this paper as: Verghese TS, Futaba K, Latthe P. Constipation in pregnancy. The Obstetrician & Gynaecologist 2015;17:1115.

Introduction

Constipation is a frequent and debilitating problemworldwide. It

affects twice as many women as men.1 In 2010, 15.9 million

prescriptions were dispensed in the community in England for

laxatives, at a cost of 70.6 million.2 Treatment of chronicconstipation can be difficult and in some cases women may

require years of treatment. Detailed prognostic data are currently

unavailable and long-term adverse effects are unknown.

Functional (primary) constipation is defined as infrequent

bowel motion and/or difficulty in passing stool, which is not

attributable to an underlying pathology.1 Secondary

constipation results from either pharmacotherapy or a

medical condition. Medical conditions include primary

disease of the gastrointestinal tract (such as, anal fissure,

colorectal strictures and neoplasia), metabolic disturbances

(such as, hypothyroidism, hypercalcaemia) and neurological

disorders. Some individuals may suffer from irritable bowel

syndrome associated with constipation (IBS-C). Constipation

occurs in all age groups and can be particularly problematic

in the elderly. Pregnancy, immobility and change in diet can

also worsen constipation. Constipation is perhaps most

conveniently thought of as a symptom. In contrast, functional

and secondary constipation can be regarded as disorders.

The prevalence of constipation is estimated to affect

1138% of pregnancies.3 Information on bowel dysfunctionduring pregnancy is limited. Pregnant women may develop

this symptom for the first time in pregnancy or may

experience worsening of their symptoms if they had

previously suffered from constipation. The Rome III criteria

are the most commonly used classification for chronic

constipation (Table 1).4 Although it is not specifically

designed for pregnancy, a more simplified criteria that may

be more appropriate could include: low frequency of

defaecation (less than thrice per week), passage of hard

stools and/or difficulties in regularly emptying the bowels.

2015 Royal College of Obstetricians and Gynaecologists 111

DOI: 10.1111/tog.12179

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http://onlinetog.org

2015;17:1115 Review

A prospective study demonstrated that pregnant women

are most prone to developing constipation in the first two

trimesters.5 The prevalence of functional constipation in the

first and second trimester varies between 35% and 39%, is

21% in the third trimester and 17% peurperium.5 Most

women can be managed with remedies such as increasing

dietary fibre and fluid intake with or without laxatives. When

symptoms are severe or refractory to conventional measures,

referral to specialist units is recommended for further

diagnostic tests and treatment.

Pathophysiology

Changes in the levels of hormones, particularly increased

progesterone levels during pregnancy, are responsible for

reduced intestinal smooth muscle motility.6 The secretion of

motilin, a peptide hormone which stimulates smooth muscle

motility, is inhibited by the rise in the level of serum

progesterone and somatostatin.7,8 Another hormone which

exhibits inhibitory effects is relaxin, which acts on the

myometrium and appears to contribute to intestinal gut

hypomotility.9 During pregnancy there is an increase in water

absorption due to activation of the renin angiotensin system

resulting from high levels of circulating estrogen and

progesterone which stimulate renin secretion and

aldosterone production.10 Aldosterone stimulates sodium

and water reabsorption from the renal tract and gut. The

reduced water content leads to hardened stools.

The forward passage of faeces becomes sluggish secondary

to the contributory passive movements of the intestinal tract

and uterus eventually leading to constipation.11 Other factors

responsible for constipation in pregnancy are insufficient

water and dietary fibre such as non starch polysaccharide.12

Haemorrhoids, anal fissures, pain at the episiotomy site,

effects of pregnancy hormones and hematinics used in

pregnancy can increase the risk of postpartum constipation.13

Clinical evaluation

Women usually report symptoms such as evacuating

infrequently, passing dry hard stools associated with pain

and straining. Excessive straining can damage the pudendal

nerve leading to weakening of the pelvic floor musculature.14

It is essential to note these key symptoms as it assists in

clinical evaluation. In addition, women may also give a

history of incomplete evacuation, which may even require

digital manipulation in severe cases to allow defaecation. It is

beneficial to recognise if these symptoms persisted prior to

pregnancy. A history of laxative or enema use should be

noted along with the dosage and frequency of treatment.

Presence of comorbidities such as hypothyroidism and

diabetes mellitus should be recorded. Constipation can be

associated with other bowel conditions like haemorrhoids,

irritable bowel syndrome (IBS) and might require input from

a colorectal surgeon or gastroenterologist in

some individuals.

Treatment

Patient education, environmental modification and

reassurance that these symptoms are transient and normal

during pregnancy may be all that is required. The majority of

patients will find relief by increasing their dietary fibre and

fluid intake. There is evidence that increasing dietary

supplements such as bran or wheat fibre can improve

symptoms in pregnant women with constipation.3 Some

traditional herbal remedies have been used for short-term

relief such as Linseed. This is generally mixed in liquid or

food, for example, bread or muffins. It must be noted that

there is insufficient evidence regarding its safety during

pregnancy.15 Probiotics may also assist in improving bowel

function by conditioning the colonic flora.16 Laxatives are

recommended if dietary modifications fail to improve the

symptoms. A laxative that is effective, non-teratogenic, not

excreted in the breast milk and well tolerated should be

chosen. Antispasmodics and anticholinergics used in IBS are

contraindicated in pregnancy and should not be used.

Bulk-forming agentsBulk-forming laxatives relieve constipation by bulking faecal

mass thereby stimulating peristalsis. They are not absorbed

from the gastrointestinal tract making them one of the safest

and most suitable laxatives for use during pregnancy. This

group comprises wheat bran, ispaghula husk, methylcellulose

and sterculia. No adverse effects on the fetus have been

reported.17 Women should be advised that bulk-forming

agents act slowly and therefore can take a few days before its

benefit is noticeable. These agents may not always be effective

in improving acute symptoms and is contraindicated in

faecal impaction.

Table 1. Rome III criteria for functional constipation

Diagnostic criteria*1 Must include two or more of the following:a. Straining during at least 25% of defecationsb. Lumpy or hard stools in at least 25% of defecationsc. Sensation of incomplete evacuation for at least 25%of defecations

d. Sensation of anorectal obstruction/blockage for at least 25%of defecations

e. Manual manoeuvres to facilitate at least 25% of defecations (e.g.,digital evacuation, support of the pelvic oor)

f. Fewer than three defecations per week2. Loose stools are rarely present without the use of laxatives3. Insufcient criteria for irritable bowel syndrome

*Criteria fullled for the last 3 months with symptom onset atleast 6 months prior to diagnosis. Reproduced with permissionfrom the Rome Foundation

112 2015 Royal College of Obstetricians and Gynaecologists

Constipation in pregnancy

Osmotic laxativesOsmotic laxatives comprises lactulose, sorbitol, polyethylene

glycol (PEG), magnesium sulphate or citrate, and salts

(sodium chloride, potassium chloride). They act by

increasing osmolar tension, resulting in an increased

amount of water in the colon facilitating peristalsis and

evacuation. Lactulose and PEG are poorly absorbed

systemically. PEG is approved by the American

Gastroenterology Association and is the treatment of choice

for chronic constipation in pregnancy.18 Common side

effects are flatulence and abdominal bloating as

hyperosmolar laxatives are indigestible sugars that ferment

in the gastrointestinal tract producing excess gas. Although

no published studies exist on adverse fetal effects, preclinical

data suggest that there is no increased risk of teratogenicity.17

Lactulose is a semi-synthetic disaccharide and is best avoided

in women with diabetes and those requiring a low galactose

diet. Theoretically, prolonged use of osmotic laxatives might

lead to electrolyte imbalances.

Macrogols (like Movicol, Norgine Ltd., Middlesex, UK)

are inert polymers of ethylene glycol, which sequester fluid in

the bowel. It is licensed for use in pregnancy despite limited

information in pregnancy, as the effects on the fetus of

systemic exposure to the drug are believed to be negligible.1

Stimulant laxativesStimulant laxatives such as bisacodyl and senna act regionally

within the large intestine by reducing water absorption and

causing colonic hyper-motility. Stimulant laxatives are more

effective than bulk-forming laxatives.19 However, stimulant

laxatives should be used with caution in the third trimester as

they can stimulate uterine contractions. This has been

documented in several anthraquinone derivatives, though

not senna itself.20

Senna is partially absorbed from the gastrointestinal tract.

A large case-control surveillance study reported no increased

risk of congenital abnormalities. Senna can be excreted in

breast milk and hence caution is advised if the woman is

breastfeeding. There is minimal absorption (5%) of bisacodyl

as it has poor bioavailability. Bisacodyl has not been

associated with either teratogenic or fetotoxic effects and is

considered suitable for use in pregnancy.17

Docusate sodium acts both as a stimulant and as a

softening agent. It is an anionic wetting agent allowing

penetration of accumulated hard, dry stool by water and

salts. A case of neonatal hypomagnesaemia after maternal

overuse of docusate sodium has been reported.21 Therefore,

the use of docusate sodium should only be considered at low

doses in pregnancy if other treatments are unsuccessful.21 It is

excreted in breast milk with oral administration of docusate

sodium. Hence, it should be used with caution in

lactating mothers.

New agentsPrucalopride stimulates the serotonin 5-HT4 receptor thereby

altering colonic motility which provides the propulsive force

for defaecation. In 2010 the National Institute for Health and

Care Excellence (NICE) approved the use of prucalopride for

the management of chronic constipation in women if

treatment with two different types of laxatives at maximum

dose for a minimum period of 6 months had failed and were

being considered for invasive treatment. There are limited

data available on its use in pregnancy. It is therefore not

recommended during pregnancy and breastfeeding. Women

of childbearing potential should use effective contraception

during treatment with prucalopride.22

Newer drugs such as linaclotide and lubiprostone are

pregnancy category C drugs, which means that their use

should only be considered if the inherent benefits outweigh

the possible risks to the fetus. Linaclotide is a guanylate

cyclase-C receptor agonist. Its use has been approved for the

management of moderate to severe irritable bowel syndrome

associated with constipation (IBS-C). The mode of action is

by augmenting the concentration of extracellular cyclic

guanosine monophosphate (c-GMP), which is thought to

reduce visceral pain by decreasing pain fibre activity. In

addition, it also increases the concentration of intracellular c-

GMP resulting in increasing secretion of electrolytes

(chloride and bicarbonate) into the intestinal lumen

leading to increased intestinal fluid to ease and accelerate

passage of stool. It is metabolised within the gastrointestinal

tract and is virtually undetectable in plasma after therapeutic

doses. There is a dearth of information available for use

during pregnancy or breastfeeding.

Lubiprostone is a locally acting CIC-2 chloride-channel

activator, which augments intestinal fluid secretion and

increases motility. It is licensed and approved by NICE for

the management of chronic idiopathic constipation if

treatment with two different types of laxative at maximum

dose for a minimum period of 6 months have failed and

invasive treatment is being considered. In animal

experimentation, maternal toxicity and over-dosage (higher

than recommended human maximum dose) have detected

adverse fetal effects. It is unascertained whether these drugs

are excreted in breast milk and therefore should be used

with caution.23

Suppositories and enemasPatients suffering from faecal loading or impaction may

benefit from use of glycerine suppositories in addition to the

use of oral laxatives as necessary. The UK Teratology

Information Service advises that glycerine suppositories can

be used in pregnancy.17 No published studies exist regarding

the use of phosphate enemas during pregnancy and potential

for teratogenicity.17

2015 Royal College of Obstetricians and Gynaecologists 113

Verghese et al.

How to stop laxativesWhen regular bowel movements occur without difficulty,

laxatives can be withdrawn gradually. The reduction in the

dose of laxatives should be guided by the frequency and

consistency of the stools. Gradual withdrawal will reduce the

risk of requiring re-initiation of therapy for recurrent faecal

loading. If a combination of laxatives is used, one laxative

should be stopped at a time, reducing stimulant laxatives

first. Patients should be aware that the process of weaning off

laxatives may take several months. Relapses often occur and

are managed by increasing the dose of laxatives promptly.

Individuals with a medical or pharmacological cause of

constipation may require long-term continued usage

of laxatives.

Conclusion

A detailed history and thorough physical examination play a

key role in diagnosing and managing women with

constipation in pregnancy effectively. If there are any red

flag signs and symptoms women should undergo further

investigation to rule out any serious gastrointestinal

pathology. The following circumstances warrant a prompt

referral to a gastroenterologist:

A change in bowel habit for longer than 6 weeks.

Rectal bleeding.

Known history of gastrointestinal disorders such as

inflammatory bowel disease.

A family history of colorectal cancer.

Women should be advised that it can take several months

to be successfully weaned off all laxatives.1 The first-line

therapy for constipation should commence by increasing

dietary fibre and water intake. If the first step is unsuccessful

in alleviating symptoms then laxatives should be considered

(Figure 1). Care must be taken to use the best type of laxative

to treat their symptom with minimal risk profile for the

mother and baby in pregnancy. Robustly conducted

randomised controlled trials aimed at treating postpartum

women diagnosed with constipation would be beneficial.

These trials should also address the criteria for administering

the intervention as well as their safety and effectiveness.13

Contribution of authorshipTV researched, drafted and revised the article. KF reviewed

and revised the article. PL instigated and edited the article.

All authors approved the final version.

Disclosure of interestsThere are no conflicts of interest

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Increase dietary

moderate exercise

Improvement in symptoms

Bulk-forming agentsBran, ispaghula, methylcellulose,

sterculia

No improvement

or switch to one of the following:

Note: If there is no response to one therapy, then a combination of medications from the

can be used

Osmotic laxatives Lactulose,

polyethylene glycol (PEG), sorbitol

Stimulant laxativesBisacodyl, senna

SuppositoriesGlycerol

suppositories

Figure 1. Algorithm for the management of constipation in pregnancy

114 2015 Royal College of Obstetricians and Gynaecologists

Constipation in pregnancy

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Corrigendum

In the following article1, the authors have acknowledged the incorrect statement regarding cardiotocography (CTG)

sensitivity and specificity on page 5, 2nd paragraph.

The sentence read:

Cardiotocography (CTG) is the main form of electronic fetal monitoring (EFM) used in many countries; approximately

300 000 pregnant women have CTG monitoring in the UK annually.3 It has been shown to have a low sensitivity but a

high specificity4 i.e. while a normal trace is reassuring that the fetus is well, an abnormal trace does not necessarily mean

that there is fetal hypoxia.

The statement should have read:

Cardiotocography (CTG) is the main form of electronic fetal monitoring (EFM) used in many countries; approximately

300 000 pregnant women have CTG monitoring in the UK annually.3 It has been shown to have a high sensitivity but a

low specificity4 i.e. while a normal trace is reassuring that the fetus is well, an abnormal trace does not necessarily mean

that there is fetal hypoxia.

Reference

1 Sacco A, Muglu J, Navaratnarajah R, Hogg M. ST analysis for intrapartum fetal monitoring. The Obstetrician & Gynaecologist 2015; 17:512.

DOI: 10.1111/tog.12194.

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