Constipation in Pregnancy: Which Laxative, and When

Constipation in pregnancy: how to think about it

Constipation in pregnancy is common and has two main drivers. Progesterone relaxes smooth muscle throughout the body, including the bowel, which slows transit. Later, the growing uterus adds physical pressure. Iron supplements, which many people take in pregnancy, compound it further. NHS guidance therefore starts with the measures that address transit directly: fibre, fluid and movement. Where those are not enough, laxatives are grouped by how they work. Bulk-forming agents add volume and need plenty of water. Osmotic agents such as lactulose and macrogol draw water into the bowel. Stool softeners such as docusate make stools easier to pass. Stimulant laxatives, which make the bowel contract, are generally not first choice in pregnancy. That is why the guidance points to asking a pharmacist rather than giving a single answer: the right product depends on the class, on whether you are also taking iron, and on how long you have had symptoms.

Constipation: safer choices

• Increasing fibre from fruit, vegetables, wholegrains and pulses, which NHS puts first, alongside plenty of fluids so the fibre can work.
• Gentle regular activity such as walking or swimming, which helps bowel movement as well as everything else.
• Not delaying when you need to go, and not straining, which reduces the risk of piles developing on top.
• Asking a pharmacist which laxative suits you. Bulk-forming agents such as ispaghula, osmotic agents such as lactulose and macrogol, and stool softeners such as docusate are different classes with different considerations.
• Mentioning it at antenatal appointments if it is persistent, particularly if you take iron tablets, which commonly worsen it.

Constipation: what to avoid or double-check

• Do not start stimulant laxatives such as senna or bisacodyl without advice. They are not usually the first choice in pregnancy.
• Avoid straining and long periods sitting on the toilet, both of which contribute to piles.
• Do not simply stop prescribed iron because it is constipating. Ask about the dose, the form, or taking it differently rather than stopping.
• Do not ignore constipation with severe abdominal pain, vomiting, bleeding, or inability to pass wind, which need assessment rather than a laxative.

How SafeMama helps

SafeMama can identify which laxative class a product belongs to and what it contains, including ispaghula, lactulose, macrogol, docusate, senna and bisacodyl, so you can take a specific product to a pharmacist rather than a general question.

Open the SafeMama app, scan the barcode or search the ingredient, then use the result as a starting point for a conversation with your healthcare provider.

Sources

• NHS constipation
• NHS medicines in pregnancy