Knowing your safe period has become something hard for the youth of today,mothers have refused to talk to us about the process of maturity,as one moves from kindergarten to junior and high school,so as our body develop from childhood to adulthood,
Churches feel uncomfortable  to talk about sex education but yet they supend people who becomes victim of ignorance,The government spend a lot on condom and contraceptives but forget to educate the mass about understanding  their system.this article will throw more light on Safe Period and Pregnancy 

The following is the best & safe method to avoid pregnancy:- 
First, you must know the duration of the cycle, thats is the first day of the last menstrual bleeding to the first day of the present menstrual bleeding. This is the duration of the menstrual cycle. but this duration may varies from person to person and it can be between 26 to 31 days
 
Ovulation occurs when a mature egg is released from the ovary, pushed down the fallopian tube, and is available to be fertilized
Ovulation approximately occurs in the middle of the cycle, i.e. duration of the cycle - (minus) 14 days (this also varies). 

A week before and a week after the approximate day of ovulation is considered to be Fertile period. 

The days apart from this is called the safe periods, where the fertilization does not takes place. 

So, to calculate the safe period you must know the fertile period. 

Calculation of fertile period: The shortest cycle minus 18 days=1st day of fertile period. The longest cycle minus 10 days= last day of fertile period. 

Ex: if a women's menstrual cycle varies from 26days to 31days cycle, 
The shortest cycle [26days] minus18days=8th day. 
The longest cycle [31days] minus 10days=21st day. 

Thus, 8th to 21st day of each cycle counting from first day of menstrual period is considered as fertile period. 

Period other than this fertile period in a menstrual cycle is considered as SAFE PERIOD. 

If one wants to avoid pregnancy avoid intercourse during fertile period. Safe period is safe for sexual activity.
Article compiled by Dr. Emmanuel Duah  
Other source by Dr. Vidya Sagar