No woman ever miscarried because of the smell of the holy [meat]...
From the ten miracles of the Holy Temple, Ethics of the Fathers, 5:5
There are those who would limit the number of their offspring for a variety of social and economic reasons. At times, the rationale for family planning assumes positive, even "holy" guises: less children means more time and energy to educate them properly, more money to give to charity, etc.
Says the mishnah, "no woman ever miscarried because of the smell of the holy." Nothing, be it the loftiest and holiest of considerations, can ever justify the prevention of the creation of another life.
Pregnancy and.postpartum can be absolute torture physically and mentally for some women. A man cannot possibly understand this and rabbis should not blindly follow the "ideal" that birth control is NEVER warranted.
Rabbis do not blindly follow that ideal, each woman's situation is handled with care and attention and if birth control is truly needed, rabbis will permit it.