For my L&D data sheet, there's a part that asks about lab values. Here's what it says:
"Lab tests done during labor: include routine (CBC, HBsAg, RPR, HIV, blood bank testing) and any additional lab work.
Please write out ALL LABS. State rationale for labs ordered. "Routine" is not a rationale.
(Consider physiologic changes of pregnancy and previous results noted in prenatal record)."
So let me see if I can reason through this...
Platelets pertain to clotting. Women with lower than normal lab values for platelets have a diminished clotting ability. Thus they're at a risk of life-threatening bleeding (or hemorrhage) during the delivery process.
WBCs are a non-specific indication of infection. If the pregnant woman has really low or really high WBC levels, r/t normal values, that means she's at a greater risk of getting an infection which could be harmful to both her and her baby.
I don't know why they look at Hct and Hgb, though.