What should you know about magnesium for pregnancy constipation?

Some magnesium preparations draw water into the bowel, making stool softer and easier to pass. Constipation can also be affected by pregnancy hormones, reduced movement, changes in diet, iron supplements or pressure from the growing uterus. A supplement is not automatically suitable simply because it is sold without a prescription. People with kidney disease may retain magnesium, and some products can cause diarrhoea, cramping or nausea.

Ask your midwife, obstetrician or pharmacist which form is appropriate before starting it. Drink fluids regularly unless you have been told to restrict them, add fibre gradually, and take gentle movement such as walking if comfortable. Review iron or other medicines with your maternity team rather than stopping them yourself. A nutrition counsellor can help build a pregnancy-appropriate eating plan.

Seek prompt medical advice for severe or worsening abdominal pain, repeated vomiting, a swollen abdomen, blood in the stool, fever, or inability to pass stool or gas. Contact your maternity team if constipation persists despite simple measures or if diarrhoea follows magnesium and you feel faint or cannot keep fluids down. Dehydration can develop when fluid losses are not replaced.

Which magnesium product, if any, fits my pregnancy and medical history? Could another treatment be safer with my current medicines? Should my iron supplement or diet be reviewed? What symptoms mean I should call the maternity unit?