מש"כ בענין הנהגת יולדת וכו' - יעוין שו"ע אדה"ז סוספ"ח, דעיקר הקפידא היא בנוגע להשם, גם בזה מקיל. - ולכן, לפע"ד, אין לה לשנות ממנהגה בקריאת שיחות ולימודן (וגם משום צניעות יש בזה). ותע"ב.
Regarding what you wrote about the conduct of a woman after childbirth, etc.—see Shulchan Aruch Admur HaZaken, end of Siman Pei Chet, that the main strictness concerns the Divine Name, and even in this there is leniency.
Therefore, in my opinion, she should not change her custom regarding reading and studying Sichos (and there is also a matter of modesty involved). Awaiting good news.
Summary
The Rebbe writes that a woman after childbirth does not need to change her custom of reading or studying Sichos, as the main concern is with G‑d's name and even there there is room for leniency. Modesty is also a factor to consider.