Pregnancy and Blood Pressure

Routine blood pressure and urine protein check-up during antenatal care is for the early detection of a condition known as pre-eclampsia, also known as pre-eclamptic toxaemia, or just toxaemia.

Pre-eclampsia is a serious pregnancy disorder characterised by high maternal blood pressure, protein in the urine and severe fluid retention. It is a fairly common complication of pregnancy and one to two percent of cases are severe enough to threaten the lives of both the mother and her unborn child.

There is no cure for the condition, except delivery of the baby.

Risk factors

• First pregnancy or a new partner
• Family history
• Diabetes mellitus
• Multiple pregnancy
• Obesity
• Extremes of maternal age
• Pre-existing hypertension
• Hydatidiform mole (A relatively rare mass or tumour that can form within the uterus at the beginning of a pregnancy)
• Hydrops Fetalis

The mother's blood pressure usually returns to normal as soon as the baby is delivered.

Signs & symptoms

Pre-eclampsia can be asymptomatic, and may develop at any time after 20 weeks of pregnancy, but commonly develops during the later stages of pregnancy.

Pre-eclampsia most commonly causes high blood pressure and protein in the urine. Some advanced symptoms include:

• Hand and face swelling
• Headache
• Visual disturbance
• Upper abdominal pain
• Dizziness
• Nausea & vomiting

Complications for the foetus

The placenta in the uterus is a special organ that allows oxygen and nutrients to pass from the mother's bloodstream to the baby, and waste products (such as carbon dioxide) to pass from the baby's bloodstream to the mother. In pre-eclampsia, blood flow to the placenta is obstructed. In severe cases, the baby can be gradually starved of oxygen and nutrients, which may affect its growth. All these lead to:

• Neonatal asphyxia (low oxygen)
• Neonatal hypoglycaemia (low glucose)
• Intrauterine growth restriction (low birthweight)

This growth restriction threatens the life of the baby and it may be necessary to deliver the baby prematurely. Another serious complication of pre-eclampsia is abruption, which means the placenta separates from the uterine wall and the woman experiences vaginal bleeding and abdominal pain. This is a medical emergency.

Management