To avoid a number of problems (see Chupat Niddah), it is strongly recommended that the wedding be scheduled for a date when the bride will not be niddah. She should choose a date at least one week after she expects all bleeding to have ceased, allowing her enough time to count seven blood-free days and then immerse in the mikveh before the wedding. (Unlike a married woman, a bride does not need to wait five days from the onset of her menses, but may perform the hefsek taharah as soon as she stops bleeding.) But, since it is impossible to predict menstruation exactly, it is best to set the wedding date somewhat later than this minimum.
A bride who has never had relations becomes niddah after first intercourse due to hymenal bleeding (dam betulim). Therefore, she should ideally try to schedule the wedding shortly before she expects her next menses, so that her period coincides with this initial separation. On the other hand, because some couples do not achieve relations on their wedding night, due to fatigue or inexperience, it is wise to leave a margin of a few days before the menses are due.
This scheduling may be relatively easy if the bride has a very regular cycle, and is planning a short engagement. Sometimes, however, it is difficult to find a suitable date, and the excitement and stress surrounding the wedding can also lead to an irregular cycle. Therefore, many brides take hormones to regulate their cycles, even if they normally menstruate regularly.
There are two medical approaches. One is to use birth control pills (which presents no halachic problems for unmarried women). It is best to begin a few months in advance, so that any breakthrough bleeding from the pills can be controlled before the wedding. Alternatively, progesterone may be used to delay menstruation for a few days, or to bring menstruation forward by taking the medication and withdrawing it. The decision to use these medications depends on the regularity of the woman's cycle, her medical history, and her personal preference. She should discuss her situation with a gynecologist or family doctor, making sure that her doctor understands that all bleeding must stop at least seven days prior to the day she plans to immerse before the wedding.
One method of manipulating the menstrual cycle is to take two or three packages of active birth control pills consecutively, without allowing a break for bleeding. Some women, especially those just starting to combine packages, experience significant bleeding during the second or third package. Therefore, to minimize the chance of a chupat niddah, we strongly recommend against combining packages immediately before the wedding.
Even with the best of planning, problems sometimes arise. A couple in these circumstances should remember that marriage is meant to last forever, and a few difficult weeks in the beginning should not overshadow a lifetime of happiness.