High blood pressure during pregnancy, including conditions like gestational hypertension and preeclampsia, is caused by a combination of factors, though the exact mechanisms are not fully understood. Key causes and risk factors include:

• Placental problems: Preeclampsia is believed to start with abnormal development or function of the placenta's blood vessels, leading to poor blood flow between mother and baby. This can cause the mother's blood pressure to rise and affect organs such as the kidneys and liver

• Pre-existing conditions: Chronic hypertension before pregnancy, kidney disease, diabetes, and autoimmune diseases increase the risk of high blood pressure during pregnancy

• Obesity: A body mass index (BMI) over 30 is a significant risk factor for hypertensive disorders in pregnancy

• Age: Women younger than 18 or older than 35 have higher risk, with advanced maternal age being linked to increased prevalence of chronic hypertension and other comorbidities

• First pregnancy: Being pregnant for the first time (nulliparity) is associated with higher risk of preeclampsia and gestational hypertension

• Multiple gestation: Carrying twins or more increases the risk due to greater placental demand

• Family or personal history: A family history of high blood pressure during pregnancy or a personal history of preeclampsia raises the risk significantly

• Other factors: Smoking, alcohol use, lack of physical activity, high cholesterol, and certain genetic factors may also contribute

In summary, high blood pressure in pregnancy results from complex interactions between maternal health, placental function, and genetic and environmental factors. The placenta's impaired blood vessel development is central to preeclampsia, while chronic conditions and lifestyle factors predispose to gestational hypertension

. Early detection and management are crucial to reduce risks for both mother and baby.