adcelannotate = {"mobilepaywallcategory" : "MOBILE_PREM-LOCAL","nativepaywallcategory" : "NATIVE_PREM-LOCAL"};Preeclampsia affects about 1 in 20 pregnancies in the United States and can lead to premature births and life-threatening complications for mothers. No one knows exactly what causes it, and diagnosing it can be tricky. Currently, doctors must rely on symptoms such as high blood pressure and protein in the urine to identify the condition.