7 mo postpartum. hypertension right after birth. resolved quickly. now have protein in urine (0.42g/24 hr). creatine tests normal. possibilities?

Urine : You have 420mg of protein which is above normal threshold but not enough to suggest disease. The fact you have Pregnancy associated htn suggest you should follow your BP. I would recheck your urine test and would also check micro albumin urine. Future urine for protein and urine for creatinine ratio is as reliable as a 24 hr and can be used to follow progression.