Final answer:
The most likely complication she might experience after postpartum tubal ligation is Pelvic Inflammatory Disease (PID), which can lead to infertility.
Step-by-step explanation:
The most likely complication she might experience after postpartum tubal ligation is Pelvic Inflammatory Disease (PID). PID is an infection of the uterine tubes or other reproductive organs that can occur due to bacteria or contagions entering the vagina and spreading to the tubes and pelvic cavity. PID can lead to the formation of scar tissue in the tubes, which can cause infertility.