Hi Im 20 Weeks Pregnant, My Vagina Has Been Itchy

Hi im 20 weeks pregnant, my vagina has been itchy for few days so iwent to the nearest clinic, iwas injected with kocef-500 injection, varimax azithromycin 250g and candizole vaginal tablet 500mg the nurse wasnt specific with the causes of my std, she said my partner should come for his treatment? Iwould like to knw more on the causes