Constipation During Pregnancy: How Fibre and Fluids Help

Constipation affects a large proportion of pregnant women, particularly in the first and third trimesters, and while it’s rarely a medical concern in itself, it can be genuinely uncomfortable and — left unmanaged — contribute to other issues like haemorrhoids. The good news is that dietary changes are usually the most effective first step, often more so than any other intervention.

Why Pregnancy Causes Constipation

Progesterone, the hormone that rises through pregnancy, relaxes smooth muscle throughout the body — including the muscles of the digestive tract, which slows the movement of food through your gut. In later pregnancy, the growing uterus also puts physical pressure on the bowel. Iron supplements, if you’re prescribed them for anaemia, are a well-known additional cause of constipation, so if your constipation started or worsened around the same time as starting iron, that’s worth noting.

Fibre: The First Line of Defence

Increasing fibre intake is the single most effective dietary change for most women. Fibre adds bulk to stool and helps it move through the digestive tract more easily. Good sources include:

• Wholegrains — wholemeal bread, brown rice, wholewheat pasta, oats
• Pulses — lentils, beans, chickpeas
• Fruit — particularly with skin left on (apples, pears), and dried fruit like prunes and figs, which have a well-established reputation for helping specifically with constipation
• Vegetables — especially those eaten with skin on, like potatoes
• Nuts and seeds — particularly flaxseed and chia seeds

It’s worth increasing fibre gradually rather than all at once, since a sudden large increase can cause bloating and discomfort before your gut adjusts.

Fluids Matter Just as Much as Fibre

Fibre without enough fluid can actually make constipation worse, since fibre absorbs water as it moves through the gut. Aim for around 8-10 glasses of fluid a day — water is best, but herbal teas (checking our herbal tea guidance for which are recommended) and diluted juice count too. See our hydration guide for more detail on fluid needs generally.

Movement Helps Too

Gentle regular activity — walking is the simplest option — helps stimulate digestive movement. This is one of several reasons staying appropriately active through pregnancy (within the guidance covered in our exercise section) is beneficial beyond fitness alone.

Prunes and Prune Juice Specifically

Prunes deserve a specific mention because they contain sorbitol, a natural sugar alcohol with a well-documented mild laxative effect, on top of their fibre content. A small handful of prunes or a small glass of prune juice is a commonly recommended, food-based first step before reaching for anything else.

When to Speak to Your Midwife

If dietary changes don’t help within a week or two, or if constipation is severe, painful, or accompanied by bleeding, it’s worth mentioning to your midwife or GP. Pregnancy-safe laxatives exist and are commonly prescribed when diet alone isn’t sufficient — this is a common, manageable issue, not something to just endure.