What should you know about flank pain during pregnancy?

As pregnancy progresses, posture, ligaments, and the muscles supporting the back and pelvis change. These changes can cause an ache that varies with position, walking, lifting, or prolonged standing. The growing uterus can also alter urinary drainage. A urinary tract infection or kidney infection may cause burning or frequent urination, fever, chills, nausea, or flank pain; a kidney stone may cause intense waves of pain, sometimes toward the groin, with nausea or blood in the urine. Do not assume flank pain is a normal pregnancy symptom when it is persistent or accompanied by other changes.

Contact your maternity team, midwife, obstetric clinician, or primary-care service for advice about new or ongoing flank pain. Mention how far along the pregnancy is, the location, severity, triggers, urinary symptoms, temperature, bleeding, contractions, and fetal movement when relevant. Rest in a comfortable position and avoid heavy lifting. Use only medicines that your pregnancy clinician or pharmacist has confirmed are suitable; do not use leftover antibiotics.

Seek urgent maternity or emergency care for severe or worsening pain, fever or chills, repeated vomiting, faintness, vaginal bleeding, fluid leakage, regular contractions, reduced fetal movement, inability to pass urine, or blood in the urine. Sudden breathlessness or chest pain also needs emergency help.

Could this be muscular, urinary, or pregnancy-related pressure? Should I provide a urine sample? Which symptoms mean I should go directly to maternity or emergency care?