סימן קנ סעיף יב

כְּשֶׁיֵשׁ חַס וְשָׁלוֹם רָעָב בַּמְּדִינָה, שֶׁהוּקְרָה הַתְּבוּאָה בְּכֶפֶל, אַף עַל פִּי שֶׁהוּא יֶשׁ לוֹ תְבוּאָה בְּתוֹךְ בֵּיתוֹ, אוֹ שֶׁיֵשׁ חַס וְשָׁלוֹם שְׁאָר צָרָה, אָסוּר לְשַׁמֵּשׁ מִטָּתוֹ כִּי אִם בְּלֵיל טְבִילָתָהּ. וְלַחֲשׂוּכֵי בָנִים, מֻתָּר בְּכָל עוֹנָה.

If, God forbid, there is [such] famine in the land that the price of grain [food] doubled,²⁰If food is generally available, it is permitted, no matter how much it costs. (Birkei Yosef, Sha’arei Teshuva 574.) even though you have sufficient grain [food] in your house, or if, God forbid, there is some other calamity [in the country],²¹Ramah 240:12. Sha’arei Tzion rules that in case of other calamaties it is not prohibited, but it is a matter of individual piety. This law generally only refers to such calamities that have a resultant effect similar to famine. marital relations are forbidden except on the night of her ritual immersion. Those who are childless²²This refers to one who has not yet fulfilled the mitzvah of propagation, which is fulfilled with the birth of a boy and a girl (Eliyohu Rabba). One whose children desecrate the Shabbos is probably considered childless with regard to this halachah. (Mishnah Berurah 574:12). are permitted to have marital relations on each appointed time of marital duty.

תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)