Fiber During Pregnancy: Targets and Safe Sources

Fiber recommendations during pregnancy increase slightly above standard adult female targets, typically to around 28 grams per day, reflecting both increased calorie needs and the fact that pregnancy hormones slow digestive transit time, which is the primary driver of the constipation that affects a large share of pregnant women, particularly in the second and third trimesters.

Iron supplementation, commonly prescribed during pregnancy, independently worsens constipation for many women, which makes deliberate fiber intake more important during pregnancy than it might otherwise be, not less — the combination of slower digestion and iron supplementation is specifically why prenatal care providers frequently raise fiber as a topic.

Whole foods remain the preferred fiber source during pregnancy over fiber supplements as a default, primarily because whole foods bring the additional nutrients — folate, iron, potassium — that pregnancy nutrition guidelines emphasize alongside fiber itself. Legumes, whole grains, and fruit with skin on cover both the fiber and the broader nutrient targets in the same foods.

The gradual-increase pacing principle applies during pregnancy as well, and water intake matters even more given the general increase in fluid needs during pregnancy. Any specific fiber or supplement decisions during pregnancy should go through an OB or midwife rather than general content, particularly given how individualized pregnancy nutrition guidance can be.