Laminaria rods are small, thin sticks made from the dried and dehydrated stems of Laminaria seaweed, a type of brown kelp. These rods are used medically as osmotic dilators to slowly dilate the cervix by absorbing moisture from surrounding tissues, expanding up to ten times their original size. This expansion gently opens the cervix to facilitate procedures such as labor induction, surgical abortions, or intrauterine device placement. Laminaria rods also promote the release of prostaglandins, which aid in preparing the body for childbirth or other interventions. They are inserted into the cervical opening where they absorb fluid and swell, applying steady pressure that dilates the cervix over several hours.