Problem: Scientists believe this happens because of how the placenta (the organ that feeds the baby) connects to the parent's blood vessels. If the connection isn't perfect, the body releases certain proteins that cause the blood vessels to squeeze shut and become inflamed. Precipitating Factors and Predisposition (Who is at risk?) Some people are more likely to develop PIH based on their health history or certain "triggers." First-time pregnancy: People having their very first baby are at higher risk. Age: Being younger than 20 or older than 35. Existing Health Issues: Having chronic high blood pressure, kidney disease, or diabetes before getting pregnant. Multiple Babies: Carrying twins, triplets, or more. Body Weight: Having a high Body Mass Index (BMI) or being obese. Family History: If your mother or sister had PIH, you are more likely to have it too. Need Assignment Help?