menstrual cycle

to count the fertile period,

record the menstrual cycle for at least six months.

then, find the shortest and the longest cycle.

for the shortest cycle, minus the number by 18

to get the 1st day of fertile period.

whereas the longest cycle is minus by 11

to get the last day of fertile period.



shortest cycle - 18 = 1st day of fertile period

longest cycle - 11 = last day of fertile period

taken from a talk about
'Katakan Tidak Kepada Seks Luar Nikah'