Yeast infection is common during pregnancy. High hormone levels during pregnancy provide media for the growth of yeast. I am very sorry because your doctor has prescribed wrong medicine for you if you have yeast infection. Quadriderm contains Betamethasone 0.05%, gentamicin 0.1%, tolnaftate 1%, iodochlorhydroxyquin 1%. Betamethasone is not used during pregnancy. It will further aggravate the yeast infection. Genamicin also promote yeast growth. You have to use imidazole derivative like chlotrimazole, isoconazole, itraconazole or econazole topical creams. Apply cream or place tablet inside vagina and also apply on the perianal and perivulvar region. Also advise your partner to use same cream on glance penis for one week.