MIAMI (CBSMiami) – New research reveals a big increase in high blood pressure among pregnant women. The condition can pose a major health risk for both mom and baby.

Chanelle Bradley is diligent about checking her blood pressure. Now pregnant with her second child, she developed hypertension during her first pregnancy. The condition caused Bradley to deliver far earlier than expected.

“My first daughter came six weeks early, she was three pounds five and a half ounces and stayed in the NICU for about three weeks,” she said.

Bradley is among a growing number of pregnant women in the U.S. battling high blood pressure.

New research in the journal Hypertension finds the cases of women with high blood pressure when they become pregnant – or who have it diagnosed in the first two trimesters – has seen a 13-fold increase over the past four decades. The study defined high blood pressure as a reading of 140 over 90 or higher.

Dr. Amy Stoddard from UCLA Health said the increase is largely due to more women becoming pregnant later in life. She warns the condition can cause serious health risks including kidney failure, stroke and increased risk of stillbirth. Pregnant women with high blood pressure require extra pre-natal care.

“More ultrasounds to check to make sure that the baby is growing appropriately and then additional monitoring of the pregnancy as you get into the third trimester,” Dr. Stoddard said.

Bradley now takes daily medication and keeps a close watch on her blood pressure. She encourages other moms-to-be to do the same.

The study also revealed that high blood pressure during pregnancy affects black women at more than twice the rate of white women.