I had a lot of bladder infections. Should I worry about getting a kidney infection?

Yes. Bladder infections in pregnancy are more likely to progress to kidney infections than normal. Kidney infections may also cause preterm delivery, pneumonia or bacteria in the bloodstream. If you have a bladder infection and develop fever, pain going into your back or symptoms like the flu, you need to let your doctor know immediately.
Yes. Bladder infections if severe or untreated can ascend the urinary tract going from the bladder up to the ureter and into the kidney. This results in pyelonephritis which is when the kidneys are affected. Although you can get many bladder infections and never have it ascend to the kidneys, having a bladder infection would be a first step.