Is it permissible to use medication to alter the timing of the menstrual cycle to avoid its coincidence with a wedding date in Ramadan, knowing that this will result in breaking the fast for more days than usual?

It is permissible for a woman to bring forward her menstrual period, unless it is with the intention of deceiving to break the fast in Ramadan (definition) or if it causes her harm. It is better for a woman to remain in her natural state and inform her husband, and he may enjoy her in ways other than intercourse. If it is necessary, she may take something that alters the timing of her period, even if it falls within Ramadan, in which case she would break her fast and make up for it later.