Why is high blood pressure a problem during pregnancy?

High blood pressure during pregnancy poses various risks, including:

• Decreased blood flow to the placenta. If the placenta doesn't get enough blood, your baby might receive less oxygen and fewer nutrients. This can lead to slow growth (intrauterine growth restriction), low birth weight or premature birth. Prematurity can lead to breathing problems, increased risk of infection and other complications for the baby.
• Placental abruption. Preeclampsia increases your risk of this condition in which the placenta separates from the inner wall of your uterus before delivery. Severe abruption can cause heavy bleeding, which can be life-threatening for you and your baby.
• Intrauterine growth restriction. Hypertension might result in slowed or decreased growth of your baby (intrauterine growth restriction).
• Injury to your other organs. Poorly controlled hypertension can result in injury to your brain, heart, lungs, kidneys, liver and other major organs. In severe cases, it can be life-threatening.
• Premature delivery. Sometimes an early delivery is needed to prevent potentially life-threatening complications when you have high blood pressure during pregnancy.
• Future cardiovascular disease. Having preeclampsia might increase your risk of future heart and blood vessel (cardiovascular) disease. Your risk of future cardiovascular disease is higher if you've had preeclampsia more than once or you've had a premature birth due to having high blood pressure during pregnancy.