DHL is a combination of hysteroscopy and laparoscopy in a single sitting, done as part of evaluating the condition of the uterus, ovaries, and fallopian tubes of the female partner. After hysteroscopy, the doctor performs laparoscopy through the umbilicus and checks the position, size, and shape of the uterus to see if there are any abnormalities. Simultaneously, the patency of the tubes is checked by pushing a non-toxic coloured dye through the vagina into the uterus to see whether it smoothly fills and spills from both fallopian tubes.