Hamoodi

..all that will be very clear as soon as u start Obs/Gyne studying ..but shortly speaking..
Parity count (P) will increase 1 for each pregnancy passing the 24th week of gestation according to the WHO definition ( 28th in iraq

) ..no matter what happens after that time ...If miscarriage happens before that time it will be added to the Abortion count (A) .. the sum of both is called the Gravida (G) .. plus some additions for the ectopic and multiple pregnancies..
Surely it has a significance .. u must know the obstetrical history of the mother to put in mind the image relevant to the current case ..e.g: infertility,abortions,ruptures,prolapse,..etc..

Hope that clears things .. and hope other friends fill in the missing lines..

..if any

..
salam..