Jay,

G stands for gravid or number of pregnancies and P stands for para (sp) or
number of  deliveries so G2P2 means second pregnancy, 2 baby born.  G2P1 means
pregnant with her second baby (not born yet) and G1P2 would mean that she had
twins (1 pregnancy, 2 babies or births).

Felicia Henry, AAHCC & LLLL