White Coat Hypertension: A temporary rise in blood pressure during the stress of a medical visit (occurs with medical professionals often wearing a white coat).

Pregnancy Induced Hypertension (PIH): Two out of three of the following signs develop in pregnancy:
• Hypertension
• Protein in the urine
• Widespread edema (swelling)

Mild PIH: A mild increase in blood pressure with only a small amount of protein in the urine.

Moderate PIH: A moderate increase in blood pressure with significant protein in the urine.

Severe PIH: Signs include blood pressure greater than 160/110, reduced urine output, large amounts of protein in the urine, headache and changes in vision, upper abdominal pain and/or the presence of HELLP Syndrome.

HELLP Syndrome: Hemolysis (breakdown of blood cells), Elevated Liver enzymes and Low Platelets are the markers of this severe form of PIH, with or without high blood pressure.

Preeclampsia: Same as PIH.

Eclampsia: Development of seizures or coma in preeclampsia.

Chronic Hypertension in Pregnancy: High blood pressure before pregnancy or detected in the first half of pregnancy.

Superimposed Preeclampsia or PIH: Hypertension becoming worse, or protein in the urine in pregnancy, in a woman with previous history of hypertension or kidney disease.

Those at greatest risk of PIH are women who have had high blood pressure or kidney disease in the past. These women should talk to a doctor before becoming pregnant to discuss pregnancy and to adjust their medications if appropriate.

Throughout the years, PIH has been described in several ways. Toxemia was a common term used until recently but has been replaced by more precise terms (see definitions). PIH may result in liver damage, kidney failure and heart failure. There may also be neurological effects (effects on the brain) including seizures and stroke. In severe cases, the condition can be life threatening.

What’s normal?

Normally, blood pressure drops in the second three months of pregnancy and rises again near the end. An important part of every prenatal visit includes a measure of blood pressure to be sure it is staying within the normal range. The earlier blood pressure changes occur, the more serious the disease may become.

What is not normal?

If a doctor detects a significant rise in blood pressure or the blood pressure is greater than 140/90, closer follow-up will be arranged. As a first step, blood pressure readings need to be taken on several occasions to learn if there is really a problem. Some people have a rise in blood pressure simply by attending a medical office ('white coat hypertension').

Sometimes, to get a more accurate measure, a woman will be taught to record her blood pressure at home and then review the results with her doctor.

How is it treated?

Often, treatment does not require medication and may or may not require a stay in hospital. Medical leave from work, reducing activity, avoiding too much salt and caffeine may be all that is required until delivery. Birth of the baby is the ultimate cure for PIH. Smoking and alcohol should always be avoided in pregnancy.

The signs that PIH may be occurring or worsening include sudden weight gain, widespread or dramatic swelling (not just the lower leg swelling common to normal pregnancy), changes in vision such as spots before the eyes or blurred vision, headache, pain and tenderness at the top of the abdomen, nausea and generally feeling unwell. Tests are done to check the severity of PIH. These include blood tests, checking the urine for protein and assessing the baby's health with movement counting charts, ultrasound and fetal heart monitor strips.

If the mother is admitted to hospital, the baby’s development inside the uterus will be checked regularly. In PIH, the flow of blood to the baby through the placenta can be severely limited. The result can be a very small baby, premature birth, placental abruption (separation of the placenta from the wall of the uterus) or stillbirth. Often, labor is induced to deliver the baby early.

The mother is watched for evidence of liver damage, kidney failure and uncontrolled high blood pressure. She may be asked to collect all her urine for 24 hours for testing or to urinate on a test strip several times a day to measure the level of protein in the urine. The clotting factors in her blood may be affected and will also require testing. Knee reflexes will likely be checked in case neurological problems are developing.

Various medications are used to treat PIH. Some women who are known to be at risk for PIH are advised to take low dose aspirin (80 mg) beginning early in pregnancy. Some doctors believe extra calcium helps prevent the condition. Most drug treatment involves controlling the blood pressure with medication and trying to prevent seizures with sedatives or other agents. Two common drugs used for this purpose are DilantinTM and magnesium sulphate. Both can have serious side effects and are only used under close supervision.

Delivery of the baby is the treatment of choice in PIH. When deciding the best time for the birth, the doctor must weigh the risks of a premature baby against the risks to the health of mother and baby if she remains pregnant.

During labor and delivery, both mother and baby are observed carefully. Pain relief such as an epidural may be used to try to reduce the mother's stress levels and keep her blood pressure and condition stable. After delivery, PIH can continue to occur, so blood pressure is monitored until it returns to normal. If medications are necessary after delivery, their effect on breast feeding must be considered.

It is still not possible to identify all the women at risk of PIH. Very few women will develop severe PIH and require all the treatments mentioned but even in milder PIH, care needs to be taken to prevent complications that can be life-threatening to mother and baby.