Preeclampsia can strike fast and unpredictably.

It's also increasingly common in the US, rising by 25% over the past 2 decades with no clear explanation.

Between 5-8% of all pregnant women develop preeclampsia or another hypertension-related disorder, including 400,000 in the US annually.

Most women who develop the condition will deliver healthy babies at term, but if left untreated or unrecognized, the mother can develop seizures or a stroke and in some rare cases, die.

Sometimes, preeclampsia results in a baby being delivered early and having complications from premature birth.

Birth of the baby is the only cure, as birth also removes the placenta, where the disease begins.

Preeclampsia is responsible for up to 500,000 infant deaths and 76,000 maternal deaths worldwide. The rate of preeclampsia in the US is 3-4 times higher than in other developed countries.

And no one seems to know why.

"Preeclampsia has been talked about for hundreds of years, yet it remains a mystery," says Dr. Sarah Kilpatrick, chair of the Department of Obstetrics and Gynecology. Dr. Kilpatrick has treated over 1,000 women with preeclampsia.

"We don't know why some patients develop preeclampsia and some don't, or who will develop severe symptoms."

The key symptoms of preeclampsia include:

• High blood pressure, usually after 20 weeks of pregnancy
• Signs of organ difficulty, including traces of protein in the urine
• Severe headaches
• Nausea or vomiting
• Vision changes, including blurry vision, light sensitivity, or temporary loss of vision
• Decreased platelet levels in the blood
• Shortness of breath

Read: Scientific Dream Team Aims to Make Preeclampsia a Relic of the Past

If preeclampsia is mild and occurs after 37 weeks of pregnancy, treatment may include:

• Delivering the baby
• Regular blood pressure and urine tests to monitor progression of the condition
• Treating the mother with magnesium sulphate to prevent seizures

Read: Bridging the Data Gap on Hypertension During Pregnancy

In more severe cases that occur earlier in the pregnancy, treatment might include:

• Admitting women to the hospital for close monitoring
• Medications for the baby's lung development, to manage the mother's blood pressure, and to prevent seizures
• Delivering a baby at 34 weeks to ensure better outcomes

Dr. Kilpatrick is working with 2 leading preeclampsia researchers: Dr. Ravi Thadhani and Dr. Ananth Karumanchi, who are both kidney specialists at Cedars-Sinai. They have devoted much of their careers to addressing preeclampsia in ways that benefit both mothers and their unborn children.

"This disease keeps you very humble because the progression is so dramatic in some patients," Dr. Karumanchi says.

"Women's lives are at stake. We have to change that."

The team aims to better understand which patients with preeclampsia are at the highest risk of developing severe symptoms that could quickly become life-threatening. If a diagnostic test to help guide important medical decisions is proven, their next step would be honing treatment approaches.

Women diagnosed with preeclampsia also look for answers about why this happened to them. Dr. Kilpatrick reassures them that it's not because of anything they did.

"There's no reason for a woman to feel guilty about getting this disease," Dr. Kilpatrick says. "It's just bad luck. It's not your fault."