women are smarter than that
call it cunt conciousness
any woman in touch with her bad self knows the instant the exact instant she ovulates and abstains for 96 hours after ovulation and then good to go.
can't pinpoint the exact moment of ovulation one month? skip that month.
God made it very easy for women to control every aspect of fertility. WHY do hundreds of them bleed together when in close communities? This is no coincidence. It is a divine gift and no different than any other way you control your health.
This knowledge has been stripped from the masses on purpose.