Treating constipation during pregnancy

Article Figures & Data

Table 1

Types of laxatives

TREATMENT	MECHANISM OF ACTION	EXAMPLES
Bulk-forming agents	Luminal water binding increases stool’s bulk, making it easier to pass⁵	Psyllium, bran
Stool softeners	Stimulates net secretion of water, sodium, chloride, and potassium and inhibits net absorption of glucose and bicarbonate in the jejunum⁶	Docusate sodium or calcium
Lubricant laxatives	Decreases surface tension of bowel’s liquid contents so that more liquid remains in the stool, thereby facilitating evacuation and decreasing straining²	Mineral oil
Osmotic laxatives	Increases osmolar tension, resulting in increased water collection, distention, peristalsis, and evacuation²	Salts (eg, sodium chloride, potassium chloride), magnesium sulfate or citrate, lactulose, sorbitol, polyethylene glycol
Stimulant laxatives	Acts locally to stimulate colonic motility and decrease water absorption from large intestine⁵	Bisacodyl, senna

Table 2

Studies examining safety in pregnancy and systemic absorption of commonly used laxatives

DRUG	TYPE OF STUDY	DETAILS	OUTCOMES
Psyllium	Surveillance	100 > N < 199 during first trimester	No increased risk of malformations⁷
Docusate sodium	Prospective	N = 116 anytime during pregnancy	No increased risk of malformations⁸
	Surveillance	N = 473 during first trimester	No increased risk of malformations (1/473 = 0.2%)⁷
	Surveillance	N = 319 during first trimester	No increased risk of malformations (3/319 = 0.9%)⁹
	Surveillance	N = 232 during first trimester	No increased risk of malformations (9/232 = 3.9%)¹⁰
Lactulose	Pharmacokinetics	N = 6 adults given lactulose	Systemic bioavailability < 3%¹¹
Polyethylene glycol	Pharmacokinetics	N = 11 adults given polyethylene glycol	Not absorbed¹²
Bisacodyl	Pharmacokinetics	N = 12 adults given oral and rectal bisacodyl	Minimal absorption¹³
	Pharmacokinetics	N = 16 adults given bisacodyl suppository	Systemic bioavailability < 5%¹⁴
Senna	Case-control	N = 506 cases (260 during first trimester)	No increased risk of malformations (OR 0.8; 95% CI 0.4–1.4) or adverse pregnancy outcomes¹⁵
	Pharmacokinetics	N = 937 control (500 during first trimester); N = 10 adults given senna	Systemic bioavailability < 5%¹⁶

OR—odds ratio.
Data from Jick et al,⁷ Heinonen et al,⁸ Aselton et al,⁹ Briggs et al,¹⁰ Carulli et al,¹¹ Wilkinson,¹² Roth and Beschke,¹³ Flig et al,¹⁴ Acs et al,¹⁵ and Krumbiegel and Schulz.¹⁶