One of the obligations that apply on the festival of Purim is to conduct a Seuda, a festive meal. Strictly speaking, one is not required to eat bread at this meal; nevertheless, it is preferable to include bread, and one should indeed endeavor to eat bread at the Purim meal.
Likewise, it is preferable to eat red meat as part of the Purim Seuda; one who finds it difficult to eat red meat may substitute chicken.
All the laws of Purim, including the obligation to conduct a Seuda, apply equally to men and women. The question thus arises as to whether a woman who is scheduled to immerse in a Mikveh on the night after Purim should eat meat as part of the Purim meal. Generally speaking, a woman should refrain from eating meat on the day before she goes to the Mikveh, out of concern that pieces of meat might become lodged between her teeth, which would invalidate her immersion. Would this apply on Purim, as well, given that it is preferable to eat meat at the Purim meal?
Although the Shevet Halevi (Rabbi Shmuel Wosner, Israel, contemporary) ruled that a woman may, in fact, eat meat as part of the Seudat Purim even though she will go to the Mikveh that night, most other authorities disagree. They argue that since according to many Rabbis there is no strict obligation to eat meat at the Purim Seuda, the preference to eat meat does not override the practice for a woman to refrain from eating meat during the day prior to her immersion.
In summary, one should make an effort to eat bread and red meat with his Purim meal; one who finds it difficult to eat red meat may eat chicken, instead. However, a woman who will be immersing in the Mikveh on the night after Purim should not eat meat on Purim day, even during the Seuda.