According to WebMD, women should not douche at any point during their cycles. There is very little evidence that douching offers benefits. However, many studies identify problems that occur because of the process, such as an increased risk of cervical cancer.
WebMD explains that douching sometimes leads to vaginal infections. The typical water and vinegar mix changes a vagina's environment and encourages the growth of harmful bacteria. Women who stop douching usually have fewer vaginal infections, which are linked to early labor and endometriosis. Pelvic inflammatory disease, or PID, is also strongly linked to douching. Women who douche are 73 percent more likely to develop PID. Also, weekly douching inhibits conception. If fertilization does occur, women often have ectopic pregnancies, in which the embryo implants outside the uterus.