The Bedtime Shema
R. Berzack wrote:
I'd like to know the details of the bedtime Shema regarding a woman's obligation. I've heard that you are not allowed to talk after you have said it. Is this true? And what about reading a book afterwards?
Dear R. Berzack,
Women should recite Shema and the Hamapil blessing immediately before retiring at night. Married women customarily say the blessing with their hair covered.
One shouldn't interrupt between the Hamapil blessing and sleeping. Therefore, one should not eat, drink, or talk after saying Hamapil. Some even have the custom to omit Hampil altogether, or they say it but omit
If one says the bedtime Shema and then has difficulty sleeping, he should keep repeating the first paragraph of the Shema or other verses of supplication until sleep overtakes him. Thinking Torah thoughts is also permitted — so reading a sefer, a book of Torah thoughts, is okay.
It is known that Rav Yehuda Segal, the late Rosh Yeshiva in Manchester, used to actually fall asleep while reciting the bedtime Shema, and he would wake from time to time and carry on exactly from the place he left off!
Sources: Shulchan Aruch 239:1 Mishna Berurah, ibid. 4,7 Halichos Bas Yisrael 2:40, Rabbi Y. Y. Fuchs